Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Ni-Based catalysts.
Zeitschriftenartikel zum Thema „Ni-Based catalysts“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Zeitschriftenartikel für die Forschung zum Thema "Ni-Based catalysts" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Zeitschriftenartikel für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Liu, Ning, Sha Cui, Zheyu Jin, Zhong Cao, Hui Liu, Shuqing Yang, Xianmin Zheng und Luhui Wang. „Highly Dispersed and Stable Ni/SiO2 Catalysts Prepared by Urea-Assisted Impregnation Method for Reverse Water–Gas Shift Reaction“. Processes 11, Nr. 5 (28.04.2023): 1353. http://dx.doi.org/10.3390/pr11051353.
Der volle Inhalt der QuelleAnnotation:
The nickel-based catalyst was more active in the reverse water-gas shift reaction, but it is easy to sinter and deactivate in high temperature reaction (≥600 °C). A urea-assisted impregnation method was utilized to create a Ni/SiO2-N catalyst to increase the catalytic stability of Ni-based catalysts. For at least 20 h, the Ni/SiO2-N catalyst in the reverse water-gas shift process at 700 °C remained stable, and in the high temperature RWGS reaction, the conversion rate of CO2 of the catalyst is close to the equilibrium conversion rate. The catalysts were characterized by BET, XRD, H2-TPR, and TEM, and the results demonstrate that the Ni particles had a small particle size and exhibited strong interaction with the SiO2 support in the Ni/SiO2-N catalyst, which led to the catalyst’s good activity and stability. Urea-assisted impregnation is a facile method to prepare stable Ni/SiO2 catalysts with high Ni dispersion.
2
Yamanaka, Nobutaka, und Shogo Shimazu. „Selective Hydrogenation Properties of Ni-Based Bimetallic Catalysts“. Eng 3, Nr. 1 (11.01.2022): 60–77. http://dx.doi.org/10.3390/eng3010006.
Der volle Inhalt der QuelleAnnotation:
Metallic Ni shows high activity for a variety of hydrogenation reactions due to its intrinsically high capability for H2 activation, but it suffers from low chemoselectivity for target products when two or more reactive functional groups are present on one molecule. Modification by other metals changes the geometric and electronic structures of the monometallic Ni catalyst, providing an opportunity to design Ni-based bimetallic catalysts with improved activity, chemoselectivity, and durability. In this review, the hydrogenation properties of these catalysts are described starting from the typical methods of preparing Ni-based bimetallic nanoparticles. In most cases, the reasons for the enhanced catalysis are discussed based on the geometric and electronic effects. This review provides new insights into the development of more efficient and well-structured non-noble metal-based bimetallic catalytic systems for chemoselective hydrogenation reactions.
3
Omoregbe, Osaze, Artur J. Majewski, Robert Steinberger-Wilckens und Ahmad El-kharouf. „Investigating the Effect of Ni Loading on the Performance of Yttria-Stabilised Zirconia Supported Ni Catalyst during CO2 Methanation“. Methane 2, Nr. 1 (08.02.2023): 86–102. http://dx.doi.org/10.3390/methane2010007.
Der volle Inhalt der QuelleAnnotation:
CO2 methanation was studied on Ni-based yttria-stabilised zirconia (Ni/YSZ) catalysts. The catalysts were prepared by the wet impregnation method, where the amount of Ni content was varied from 5% to 75%. Thereafter, the prepared catalysts were analysed by BET, XRD, SEM and H2-TPR. BET results showed an initial increase in the surface area with an increase in Ni loading, then a decrease after 30% Ni loading. The XRD results revealed that the Ni crystallite size increased as the Ni loading increased, while the H2-TPR showed a shift in reduction peak temperature to a higher temperature, indicating that the reducibility of the catalysts decreased as the Ni loading increased. The activity of the synthesised catalysts for CO2 methanation was studied by passing a mixture of H2, CO2 and N2 with a total flow of 135 mL min−1 and GHSV of 40,500 mL h−1 g−1 through a continuous flow quartz tube fixed-bed reactor (I.D. = 5.5 mm, wall thickness = 2 mm) containing 200 mg of the catalyst at a temperature range of 473 to 703 K under atmospheric pressure and a H2:CO2 ratio of 4. The tested Ni/YSZ catalysts showed an improvement in activity as the reaction temperature increased from 473 K to around 613 to 653 K, depending on the Ni loading. Beyond the optimum temperature, the catalyst’s activity started to decline, irrespective of the Ni loading. In particular, the 40% Ni/YSZ catalyst displayed the best performance, followed by the 30% Ni/YSZ catalyst. The improved activity at high Ni loading (40% Ni) was attributed to the increase in hydrogen coverage and improved site for both H2 and CO2 adsorption and activation.
4
Kakinuma, Katsuyoshi, Guoyu Shi, Tetsuro Tano, Donald A. Tryk, Miho Yamaguchi, Makoto Uchida, Kazuo Iida, Chisato Arata, Sumitaka Watanabe und Akihiro Iiyama. „Anodic/Cathodic Properties of Ni Based Catalysts for Anion Electrolyte Membrane Water Electrolysis“. ECS Meeting Abstracts MA2023-01, Nr. 36 (28.08.2023): 2090. http://dx.doi.org/10.1149/ma2023-01362090mtgabs.
Der volle Inhalt der QuelleAnnotation:
Anion electrolyte membrane water electrolysis (AEM WE) using non-precious metal catalyst is one of the most prospective systems for pure hydrogen generation. The Ni based oxide shows relatively lower overpotential of oxygen evolution reaction (OER) by adding the transition metals of Co, Fe and Mn, and approaches that of precious metal of Ir based oxide. Our previous study reported that the Ni-Co based catalyst was highest OER activity at operating temperature. The crystallized Ni-Co metal-based core particles with amorphous Ni oxyhydrates of top surface (shell) was confirmed to be preferable to obtain the higher OER activity by rotating disk electrode method, transmission electron microscopy and DFT calculation. Moreover, the fused aggregated network microstructure of Ni-Co based catalyst assisted to show a metallically electronic conductivity. In this study, we evaluated both OER and hydrogen evolution reaction (HER) activity of Ni based catalysts to confirm the prospective non-precious metal catalysts for AEM WE. Each Ni based catalysts with additive of transition metals were synthesized by the flame oxide-synthesis method.1 The OER and HER activities of these catalysts were evaluated in 1 M KOH at 20 to 80 oC by use of the RDE. The Ni-Co based catalyst was highest OER activity in these Ni based catalysts obtained above. The amorphous top surface layer was correlated with a negative shift in the oxyhydroxide formation peak potential from the results of DFT calculations. 2 The HER activity of the Ni-Fe based catalyst also showed the higher OER activity. Especially, the Ni-Fe based catalyst had highest HER activity in these Ni cased catalysts above. The HER activity enhanced by the construction of well crystallized top surface in comparison with its amorphous or poorly crystalline ones. DFT calculation indicated that the defective or disordered surface was not as active for the HER. These results will provide a strategy of Ni based catalysts optimization for AEM. Acknowledgement This work was partially supported by funds for the JSPS KAKENHI (20H02839), and the project from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. References Kakinuma, M. Uchida, T. Kamino, H. Uchida, and M. Watanabe, Electrochim. Acta, 56, 2881 (2011). Shi, T. Tano, D. A. Tryk, A. Iiyama, M. Uchida, and K. Kakinuma, ACS Catal., 11, 5222 (2021). Figure 1
5
Ren, Hua-Ping, Si-Yi Ding, Qiang Ma, Wen-Qi Song, Yu-Zhen Zhao, Jiao Liu, Ye-Ming He und Shao-Peng Tian. „The Effect of Preparation Method of Ni-Supported SiO2 Catalysts for Carbon Dioxide Reforming of Methane“. Catalysts 11, Nr. 10 (10.10.2021): 1221. http://dx.doi.org/10.3390/catal11101221.
Der volle Inhalt der QuelleAnnotation:
Reforming methane to produce syngas is a subject that generates considerable interest. The process requires catalysts that possess high-performance active sites to activate stable C–H bonds. Herein, we report a facile synthetic strategy to prepare Ni-based catalysts by complexation–impregnation (Ni-G/SiO2-C) and precipitation–impregnation (Ni-G/SiO2-P) methods using glycine as a complexing agent. The particle size of Ni in both types of catalysts is decreased by adding glycine in the preparation process. Nevertheless, the preparation methods and amount of glycine play a significant role in the particle size and distribution of Ni over the Ni-based catalysts. The smaller particle size and narrower distribution of Ni were obtained in the Ni-G/SiO2-P catalyst. The catalysts were comparatively tested for carbon-dioxide reforming of methane (CDR). Ni-G/SiO2-P showed better CDR performance than Ni-G/SiO2-C and Ni/SiO2 and increased stability because of the smaller particle size and narrower distribution of Ni. Moreover, a high-performance Ni-based catalyst was prepared by optimizing the amount of glycine added. An unobservable deactivation was obtained over Ni-G-2/SiO2-P and Ni-G-3/SiO2-P for CDR during TOS = 20 h. Thus, a new promising method is described for the preparation of Ni-based catalysts for CDR.
6
Matos, Juan, und Maibelin Rosales. „Promoter Effect upon Activated Carbon-Supported Ni-Based Catalysts in Dry Methane Reforming“. Eurasian Chemico-Technological Journal 14, Nr. 1 (15.12.2011): 5. http://dx.doi.org/10.18321/ectj91.
Der volle Inhalt der QuelleAnnotation:
<p>The influence of selected promoters such as Ca, Mg, Cu and Zn upon activated carbon-supported Ni-based catalysts in the dry methane reforming under mild experimental conditions (650 ºC, 1 atm) was verified. It was found that Ni-Mg catalyst showed the highest initial catalytic activity followed by NiCa/AC catalyst. As expected, catalysts promoted with the most basic oxides such as MgO or CaO showed moderate deactivation after 4 h reaction ascribed to the basic Lewis behaviour which stabilize Ni-based catalysts.</p>
7
Kim, Jaerim, Sang-Mun Jung, Yong-Tae Kim und Jong Kyu Kim. „Efficient Alkaline Hydrogen Evolution Reaction Using Superaerophobic Ni Nanoarrays with Accelerated H2 Bubble Release“. ECS Meeting Abstracts MA2023-02, Nr. 42 (22.12.2023): 2150. http://dx.doi.org/10.1149/ma2023-02422150mtgabs.
Der volle Inhalt der QuelleAnnotation:
Water electrolysis for producing green hydrogen is of central importance in the hydrogen economy to meet the global mission of carbon neutrality. Hydrogen evolution reaction (HER) under alkaline conditions has many advantages in cost and stability over acidic HER, but it requires high overpotential due to sluggish reaction kinetics. Pt-based materials are still considered the benchmark for HER catalysts, however, their high cost is the major hurdle for large-scale applications, motivating tremendous efforts to find earth-abundant catalytic materials as alternatives. In addition to catalytic materials, the formation and release of H2 bubbles on the surface of catalysts should be considered when designing efficient catalysts, as this significantly affects catalytic performance. Adhered H2 bubbles on the catalyst surface can cause reduced active surface sites, blockage of ion pathways, and destruction of catalyst film by inducing a large stretch force. Despite the adverse effects of H2 bubbles adhering to catalyst’s surface on the performance of water electrolysis, the mechanisms by which H2 bubbles are effectively released during the alkaline HER remain elusive. In this study, we conducted a systematic investigation on the effect of nanoscale surface morphologies on H2 bubble release behaviors and HER performance by employing earth-abundant Ni catalysts consisting of an array of Ni nanorods (NRs) with controlled surface porosities. Both aerophobicity and hydrophilicity of the catalyst’s surface vary according to the surface porosity of catalysts. The Ni catalyst with the highest porosity of ~52% exhibits superaerophobic nature as well as the best HER performance among the Ni catalysts. It was found that the Ni catalyst’s superaerophobicity combined with the effective open pore channels enables the accelerated release of H2 bubbles from the surface, leading to a significant improvement in geometric activities, particularly at high current densities, as well as intrinsic activities including both specific and mass activities. It was also demonstrated that the superaerophobicity enabled by highly porous Ni NRs can be combined with Pt and Cr having optimal binding abilities to further optimize electrocatalytic performance. Our work can help to elucidate the fundamental and practical design rules for efficient alkaline HER catalysts consisting of earth-abundant elements.
8
Xiao, Yan, Jie Li, Yuan Tan, Xingkun Chen, Fenghua Bai, Wenhao Luo und Yunjie Ding. „Ni-Based Hydrotalcite (HT)-Derived Cu Catalysts for Catalytic Conversion of Bioethanol to Butanol“. International Journal of Molecular Sciences 24, Nr. 19 (03.10.2023): 14859. http://dx.doi.org/10.3390/ijms241914859.
Der volle Inhalt der QuelleAnnotation:
Catalytic conversion of biomass-derived ethanol into n-butanol through Guerbet coupling reaction has become one of the key reactions in biomass valorization, thus attracting significant attention recently. Herein, a series of supported Cu catalysts derived from Ni-based hydrotalcite (HT) were prepared and performed in the continuous catalytic conversion of ethanol into butanol. Among the prepared catalysts, Cu/NiAlOx shows the best performance in terms of butanol selectivity and catalyst stability, with a sustained ethanol conversion of ~35% and butanol selectivity of 25% in a time-on-stream (TOS) of 110 h at 280 °C. While for the Cu/NiFeOx and Cu/NiCoOx, obvious catalyst deactivation and/or low butanol selectivity were obtained. Extensive characterization studies of the fresh and spent catalysts, i.e., X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Hydrogen temperature-programmed reduction (H2-TPR), reveal that the catalysts’ deactivation is mainly caused by the support deconstruction during catalysis, which is highly dependent on the reducibility. Additionally, an appropriate acid–base property is pivotal for enhancing the product selectivity, which is beneficial for the key process of aldol-condensation to produce butanol.
9
Deo, Yashwardhan, Niklas Thissen und Anna K. Mechler. „Electrodeposited Ni-Based Catalysts for the Oxygen Evolution Reaction“. ECS Meeting Abstracts MA2023-02, Nr. 20 (22.12.2023): 1255. http://dx.doi.org/10.1149/ma2023-02201255mtgabs.
Der volle Inhalt der QuelleAnnotation:
Alkaline water electrolysis is one of the most mature technologies for producing green hydrogen. However, there still are possibilities to enhance this process by using better electrocatalysts for the kinetically limited oxygen evolution reaction (OER). While there are several existing methods for catalyst synthesis, such as spray coating, coprecipitation and hydrothermal synthesis, they face challenges of either versatility or scalability.[1,2] In this regard, electrodeposition is a promising catalyst synthesis method, due to its excellent process control and ease of scalability. In this work, electrodeposition is used to prepare nickel-based catalysts as a benchmark system. These catalysts are deposited on expanded Ni-mesh supports. Initially, the deposition parameters are optimized to obtain uniform Ni deposits, which provide reproducible activity measurements. Herein, we observe that the deposited Ni catalysts exhibit better OER activities than the Ni mesh support, most likely due to the evolution of a pyramidal morphology with an increased surface area (Fig. 1). The optimized deposition parameters are further used to deposit different Ni-based alloys such as Ni-Fe and Ni-Co, by adding the respective ionized metal species to the Ni electrolyte. The microstructure and composition of these catalysts is analyzed using material characterization techniques like scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Finally, the OER activity and long-term stability of the deposited catalysts is evaluated in an in-house developed electrochemical beaker cell at elevated concentration, temperature, and current densities (30 wt.% KOH, 80 °C, up to 1 A/cm2). The results obtained for the different catalysts are compared to understand the correlation of the catalyst structure and composition with their electrochemical OER performance under industrial conditions. Bibliography [1] Lu Xunyu et al.; Nature Communications; DOI: 10.1038/ncomms7616 [2] Zuraya Angeles-Olvera et al.; Energies; DOI: 10.3390/en15051609 Figure 1
10
Xiao, Yan, Nannan Zhan, Jie Li, Yuan Tan und Yunjie Ding. „Highly Selective and Stable Cu Catalysts Based on Ni–Al Catalytic Systems for Bioethanol Upgrading to n-Butanol“. Molecules 28, Nr. 15 (27.07.2023): 5683. http://dx.doi.org/10.3390/molecules28155683.
Der volle Inhalt der QuelleAnnotation:
The catalytic upgrading of ethanol into butanol through the Guerbet coupling reaction has received increasing attention recently due to the sufficient supply of bioethanol and the versatile applications of butanol. In this work, four different supported Cu catalysts, i.e., Cu/Al2O3, Cu/NiO, Cu/Ni3AlOx, and Cu/Ni1AlOx (Ni2+/Al3+ molar ratios of 3 and 1), were applied to investigate the catalytic performances for ethanol conversion. From the results, Ni-containing catalysts exhibit better reactivity; Al-containing catalysts exhibit better stability; but in terms of ethanol conversion, butanol selectivity, and catalyst stability, a corporative effect between Ni–Al catalytic systems can be clearly observed. Combined characterizations such as XRD, TEM, XPS, H2-TPR, and CO2/NH3-TPD were applied to analyze the properties of different catalysts. Based on the results, Cu species provide the active sites for ethanol dehydrogenation/hydrogenation, and the support derived from Ni–Al–LDH supplies appropriate acid–base sites for the aldol condensation, contributing to the high butanol selectivity. In addition, catalysts with strong reducibility (i.e., Cu/NiO) may be easily deconstructed during catalysis, leading to fast deactivation of the catalysts in the Guerbet coupling process.
11
Kim, Hyunjoung, Young-Hee Lee, Hongjin Lee, Jeong-Cheol Seo und Kyubock Lee. „Effect of Mg Contents on Catalytic Activity and Coke Formation of Mesoporous Ni/Mg-Aluminate Spinel Catalyst for Steam Methane Reforming“. Catalysts 10, Nr. 8 (23.07.2020): 828. http://dx.doi.org/10.3390/catal10080828.
Der volle Inhalt der QuelleAnnotation:
Ni catalysts are most suitable for a steam methane reforming (SMR) reaction considering the activity and the cost, although coke formation remains the main problem. Here, Ni-based spinel catalysts with various Mg contents were developed through the synthesis of mesoporous Mg-aluminate supports by evaporation-induced self-assembly followed by Ni loading via incipient wetness impregnation. The mesoporous Ni/Mg-aluminate spinel catalysts showed high coke resistance under accelerated reaction conditions (0.0014 gcoke/gcat·h for Ni/Mg30, 0.0050 gcoke/gcat·h for a commercial catalyst). The coke resistance of the developed catalyst showed a clear trend: the higher the Mg content, the lower the coke deposition. The Ni catalysts with the lower Mg content showed a higher surface area and smaller Ni particle size, which originated from the difference of the sintering resistance and the exsolution of Ni particles. Despite these advantageous attributes of Ni catalysts, the coke resistance was higher for the catalysts with the higher Mg content while the catalytic activity was dependent on the reaction conditions. This reveals that the enhanced basicity of the catalyst could be the major parameter for the reduction of coke deposition in the SMR reaction.
12
Yang, Zhenglong, Yan Cui, Pengxiang Ge, Mindong Chen und Leilei Xu. „CO2 Methanation over Rare Earth Doped Ni-Based Mesoporous Ce0.8Zr0.2O2 with Enhanced Low-Temperature Activity“. Catalysts 11, Nr. 4 (01.04.2021): 463. http://dx.doi.org/10.3390/catal11040463.
Der volle Inhalt der QuelleAnnotation:
The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO2 methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO2. The catalysts were characterized systematically by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR), CO2 temperature programmed desorption (CO2-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal-skeleton interaction. Therefore, under the condition of CO2 methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO2. In addition, the rare earth elements also act as electron modifiers to help activate CO2 molecules. Therefore, the rare earth doped Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts are expected to be an efficient catalyst for the methanation of CO2 at low-temperature.
13
Mahy, Julien G., Thierry Delbeuck, Kim Yên Tran, Benoît Heinrichs und Stéphanie D. Lambert. „Green Chemistry for the Transformation of Chlorinated Wastes: Catalytic Hydrodechlorination on Pd-Ni and Pd-Fe Bimetallic Catalysts Supported on SiO2“. Gels 9, Nr. 4 (25.03.2023): 275. http://dx.doi.org/10.3390/gels9040275.
Der volle Inhalt der QuelleAnnotation:
Monometallic catalysts based on Fe, Ni and Pd, as well as bimetallic catalysts based on Fe-Pd and based on Ni-Pd supported on silica, were synthesized using a sol–gel cogelation process. These catalysts were tested in chlorobenzene hydrodechlorination at low conversion to consider a differential reactor. In all samples, the cogelation method allowed very small metallic nanoparticles of 2–3 nm to be dispersed inside the silica matrix. Nevertheless, the presence of some large particles of pure Pd was noted. The catalysts had specific surface areas between 100 and 400 m2/g. In view of the catalytic results obtained, the Pd-Ni catalysts are less active than the monometallic Pd catalyst (<6% of conversion) except for catalysts with a low proportion of Ni (9% of conversion) and for reaction temperatures above 240 °C. In this series of catalysts, increasing the Ni content increases the activity but leads to an amplification of the catalyst deactivation phenomenon compared to Pd alone. On the other hand, Pd-Fe catalysts are more active with a double conversion value compared to a Pd monometallic catalyst (13% vs. 6%). The difference in the results obtained for each of the catalysts in the Pd-Fe series could be explained by the greater presence of the Fe-Pd alloy in the catalyst. Fe would have a cooperative effect when associated with Pd. Although Fe is inactive alone for chlorobenzene hydrodechlorination, when Fe is coupled to another metal from the group VIIIb, such as Pd, it allows the phenomenon of Pd poisoning by HCl to be reduced.
14
Kim, Tae-Young, Seongbin Jo, Yeji Lee, Suk-Hwan Kang, Joon-Woo Kim, Soo-Chool Lee und Jae-Chang Kim. „Influence of Ni on Fe and Co-Fe Based Catalysts for High-Calorific Synthetic Natural Gas“. Catalysts 11, Nr. 6 (31.05.2021): 697. http://dx.doi.org/10.3390/catal11060697.
Der volle Inhalt der QuelleAnnotation:
Fe-Ni and Co-Fe-Ni catalysts were prepared by the wet impregnation method for the production of high-calorific synthetic natural gas. The influence of Ni addition to Fe and Co-Fe catalyst structure and catalytic performance was investigated. The results show that the increasing of Ni amount in Fe-Ni and Co-Fe-Ni catalysts increased the formation of Ni-Fe alloy. In addition, the addition of nickel to the Fe and Co-Fe catalysts could promote the dispersion of metal and decrease the reduction temperature. Consequently, the Fe-Ni and Co-Fe-Ni catalysts exhibited higher CO conversion compared to Fe and Co-Fe catalysts. A higher Ni amount in the catalysts could increase C1–C4 hydrocarbon production and reduce the byproducts (C5+ and CO2). Among the catalysts, the 5Co-15Fe-5Ni/γ-Al2O3 catalyst affords a high light hydrocarbon yield (51.7% CH4 and 21.8% C2–C4) with a low byproduct yield (14.1% C5+ and 12.1% CO2).
15
Park, Ho-Ryong, Beom-Jun Kim, Yeol-Lim Lee, Seon-Yong Ahn, Kyoung-Jin Kim, Ga-Ram Hong, Seong-Jin Yun, Byong-Hun Jeon, Jong Wook Bae und Hyun-Seog Roh. „CO2 Reforming of CH4 Using Coke Oven Gas over Ni/MgO-Al2O3 Catalysts: Effect of the MgO:Al2O3 Ratio“. Catalysts 11, Nr. 12 (30.11.2021): 1468. http://dx.doi.org/10.3390/catal11121468.
Der volle Inhalt der QuelleAnnotation:
Research is being actively conducted to improve the carbon deposition and sintering resistance of Ni-based catalysts. Among them, the Al2O3-supported Ni catalyst has been broadly studied for the dry reforming reaction due to its high CH4 activity at the beginning of the reaction. However, there is a problem of deactivation due to carbon deposition of Ni/Al2O3 catalyst and sintering of Ni, which is a catalytically active material. Supplementing MgO in Ni/Al2O3 catalyst can result in an improved MgAl2O4 spinel structure and basicity, which can be helpful for the activation of methane and carbon dioxide molecules. In order to confirm the optimal supports’ ratio in Ni/MgO-Al2O3 catalysts, the catalysts were prepared by supporting Ni after controlling the MgO:Al2O3 ratio stepwise, and the prepared catalysts were used for CO2 reforming of CH4 (CDR) using coke oven gas (COG). The catalytic reaction was conducted at 800 °C and at a high gas hourly space velocity (GHSV = 1,500,000 h−1) to screen the catalytic performance. The Ni/MgO-Al2O3 (MgO:Al2O3 = 3:7) catalyst showed the best catalytic performance between prepared catalysts. From this study, the ratio of MgO:Al2O3 was confirmed to affect not only the basicity of the catalyst but also the dispersion of the catalyst and the reducing property of the catalyst surface.
16
Jiang, Hong Tao, Wei Hua, Hui Quan Li und Yong Chuan Dai. „Recent Progresses on Some Coke Resistant Ni-Based Catalysts for Carbon Dioxide Reforming of Methane“. Advanced Materials Research 650 (Januar 2013): 85–91. http://dx.doi.org/10.4028/www.scientific.net/amr.650.85.
Der volle Inhalt der QuelleAnnotation:
Carbon dioxide reforming of methane (CDR) can convert two greenhouse gases, methane can carbon dioxide, into useful syngas. Nickel-based catalysts have been extensively investigated due to their high activity and low cost. However, coke formation over Ni catalyst is serious and leads to rapid deactivation of the catalyst. Coke resistant Ni catalyst for CDR reaction is desired. In this paper, recent progresses in the design and preparation of coke resistant Ni catalysts supported on solid solutions, zeolite, perovskites and perovskite type oxides, hexaaluminates or substituted hexaaluminates, pyrochlore, montmorillonites, and hydrotalcites for CDR were summarized. The progresses in the use of promoters, in the effect of supporting materials and in the preparation methods have been discussed. The future development of coke resistant Ni catalysts for these processes is briefly addressed.
17
Rodiansono, Rodiansono, Maria Dewi Astuti, Dwi Rasy Mujiyanti und Uripto Trisno Santoso. „Selective Hydrogenation of Sucrose into Sugar Alcohols over Supported Raney Nickel-Based Catalysts“. Indonesian Journal of Chemistry 19, Nr. 1 (29.01.2019): 183. http://dx.doi.org/10.22146/ijc.31319.
Der volle Inhalt der QuelleAnnotation:
Selective hydrogenation of sugars (e.g. sucrose, cellobiose, glucose, fructose, xylose, arabinose) into sugar alcohols (sorbitol, mannitol, xylitol, arabitol) can be achieved by means of supported Raney Ni-based catalysts. Various supporting materials such as the layered structure of clay (e.g. bentonite, taeniolite, smectite), metal oxides (e.g. Nb2O5, ZrO2, Al2O3), and conventional supports (e.g. carbon, silica, zeolite (JRC-SZ1)) were employed to obtain high performance of supported Raney Ni-based catalysts. The conventional Raney Ni, Raney Ni/AlOH, and Ni-NP with relatively high dispersion exhibited superior catalytic activity compared with the various supported Raney Ni catalysts with the conversion of 100% and hexitols selectivity almost ~99%. The H2 treatment of Raney Ni/SMT at a temperature of 473–773 K caused the increase in Ni(111) crystallite sizes as the conversion of sucrose with compromised decreased of hexitols product. The presence of acidic co-catalyst such as SnO, amberlyst-15, JRC-SZ1, JRC-Z5-9OH1 on Raney Ni/AlOH catalyst significantly enhanced the formation of glycerol product even though the conversion of sucrose compromised decreased owing to the partial leaching of Ni metal into the reaction mixture.
18
Zheng, Guo Bin, Hideaki Sano und Yasuo Uchiyama. „Parameters Affecting the Structure and Yield of Carbon Nanotubes in CVD Method“. Materials Science Forum 544-545 (Mai 2007): 773–76. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.773.
Der volle Inhalt der QuelleAnnotation:
Carbon nanotubes and nanofibers were synthesized at 400-800°C by a typical CVD method using SiO2, Al2O3, or MgO supported Ni or Co catalyst, and acetylene as feedstock. The effects of temperature, substrates and catalyst on the yield and structure of carbon nanotubes and nanofibers were investigated in detail. The experimental results showed that Ni based catalysts tended to form carbon nanofibers with “herringbone” structure, though for Ni/Al2O3 catalyst, the products at 800°C changed to a structure like carbon nanotube. Co based catalysts tended to form carbon nanotubes.
19
Ibrahim, Mohamed, Fahad A. Al-Zahrani, Francisco J. Diaz, Tareq Al-Attas, Hasan Zahir, Syed A. Ali, Mohammed Abdul Bari Siddiqui und Mohammad M. Hossain. „Experimental Investigation of Metal-Based Calixarenes as Dispersed Catalyst Precursors for Heavy Oil Hydrocracking“. Catalysts 12, Nr. 10 (17.10.2022): 1255. http://dx.doi.org/10.3390/catal12101255.
Der volle Inhalt der QuelleAnnotation:
Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas oil (VGO). Co- and Ni-based TBC[6]s were synthesized and characterized by SEM-EDX, ICP, XRD, and FT-IR. The thermogravimetric and calorimetric behaviors of the synthesized complexes, which are key properties of dispersed hydrocracking catalysts, were also explored. The experimental evaluation of the synthesized catalyst precursors show that the synthesized metal-based TBC[6] catalyst precursors improved the catalytic hydrogenation reactions. A co-catalytic system was also investigated by adding a commercial, first-stage hydrocracking supported catalyst in addition to the dispersed catalysts. The naphtha yields increased from 10.7 wt.% for the supported catalyst to 11.7 wt.% and 12 wt.% after adding it along with Ni-TBC[6] and Co-TBC[6], respectively. Mixing the metal-based precursors resulted in elevated yields of liquid products due to the in situ generation of highly active Co–Ni bimetallic dispersed catalysts.
20
Saab, Roba, Kyriaki Polychronopoulou, Dalaver H. Anjum, Nikolaos Charisiou, Maria A. Goula, Steven J. Hinder, Mark A. Baker und Andreas Schiffer. „Carbon Nanostructure/Zeolite Y Composites as Supports for Monometallic and Bimetallic Hydrocracking Catalysts“. Nanomaterials 12, Nr. 18 (19.09.2022): 3246. http://dx.doi.org/10.3390/nano12183246.
Der volle Inhalt der QuelleAnnotation:
In this study, we examine the effect of integrating different carbon nanostructures (carbon nanotubes, CNTs, graphene nanoplatelets, GNPs) into Ni- and Ni-W-based bi-functional catalysts for hydrocracking of heptane performed at 400 °C. The effect of varying the SiO2/Al2O3 ratio of the zeolite Y support (between 5 and 30) on the heptane conversion is also studied. The results show that the activity, in terms of heptane conversion, followed the order CNT/Ni-ZY5 (92%) > GNP/Ni-ZY5 (89%) > CNT/Ni-W-ZY30 (86%) > GNP/Ni-W-ZY30 (85%) > CNT/Ni-ZY30 (84%) > GNP/Ni-ZY30 (83%). Thus, the CNT-based catalysts exhibited slightly higher heptane conversion as compared to the GNP-based ones. Furthermore, bimetallic (Ni-W) catalysts possessed higher BET surface areas (725 m2/g for CNT/Ni-W-ZY30 and 612 m2/g for CNT/Ni-ZY30) and exhibited enhanced hydrocracking activity as compared to the monometallic (Ni) catalyst with the same zeolite support and type of carbon structure. It was also shown that CNT-based catalysts possessed higher regeneration capability than their GNP-based counterparts due to the slightly higher thermal stability of the CVD-grown CNTs.
21
Zhang, Fanying, Bin Lu und Peiqin Sun. „Co-Promoted Ni Nanocatalysts Derived from NiCoAl-LDHs for Low Temperature CO2 Methanation“. Catalysts 11, Nr. 1 (15.01.2021): 121. http://dx.doi.org/10.3390/catal11010121.
Der volle Inhalt der QuelleAnnotation:
Ni-based catalysts are prone to agglomeration and carbon deposition at high temperatures. Therefore, the development of Ni-based catalysts with high activities at low temperatures is a very urgent and challenging research topic. Herein, Ni-based nanocatalysts containing Co promoter with mosaic structure were prepared by reduction of NiCoAl-LDHs, and used for CO2 methanation. When the reaction temperature is 250 °C (0.1 MPa, GHSV = 30,000 mL·g−1·h−1), the conversion of CO2 on the NiCo0.5Al-R catalyst reaches 81%. However, under the same test conditions, the conversion of CO2 on the NiAl-R catalyst is only 26%. The low-temperature activity is significantly improved due to Co which can effectively control the size of the Ni particles, so that the catalyst contains more active sites. The CO2-TPD results show that the Co can also regulate the number of moderately basic sites in the catalyst, which is beneficial to increase the amount of CO2 adsorbed. More importantly, the NiCo0.5Al-R catalyst still maintains high catalytic performance after 92 h of continuous reaction. This is due to the confinement effect of the AlOx substrate inhibiting the agglomeration of Ni nanoparticles. The Ni-based catalysts with high performance at low temperature and high stability prepared by the method used have broad industrial application prospects.
22
Song, Kyoung Ho, Soon Kwan Jeong, Byung Hun Jeong, Kwan-Young Lee und Hak Joo Kim. „Effect of the Ni/Al Ratio on the Performance of NiAl2O4 Spinel-Based Catalysts for Supercritical Methylcyclohexane Catalytic Cracking“. Catalysts 11, Nr. 3 (02.03.2021): 323. http://dx.doi.org/10.3390/catal11030323.
Der volle Inhalt der QuelleAnnotation:
Supercritical methylcyclohexane cracking of NiAl2O4 spinel-based catalysts with varying Ni/Al deficiencies was investigated. Thus, catalysts with Ni content of 10–50 wt.% were prepared by typical co-precipitation methods. The calcined, reduced, and spent catalysts were characterized by X-ray diffraction, O2 temperature-programmed oxidation, NH3 temperature-programmed desorption, N2 physisorption, O2 chemisorption, scanning and transmission electron microscopy, and X-ray fluorescence. The performance and physicochemical properties of the reference stoichiometric Ni3Al7 catalyst differed significantly from those of the other catalysts. Indeed, the Ni-deficient Ni1Al9 catalyst led to the formation of large Ni particles (diameter: 20 nm) and abundant strong acid sites, without spinel structure formation, owing to the excess Al. These acted with sufficient environment and structure to form the coke precursor nickel carbide, resulting in a pressure drop within 17 min. On the other hand, the additional NiO linked to the NiAl2O4 spinel structure of the Al-deficient Ni5Al5 catalyst formed small crystals (10 nm), owing to the excess Ni, and displayed improved Ni dispersion. Thus, dehydrogenation proceeded effectively, thereby improving the resistance to coke formation. This catalytic behavior further demonstrated the remarkable activity and stability of this catalyst under mild conditions (450 °C and 4 Mpa).
23
Fakeeha, Anis Hamza, Yasir Arafat, Ahmed Aidid Ibrahim, Hamid Shaikh, Hanan Atia, Ahmed Elhag Abasaeed, Udo Armbruster und Ahmed Sadeq Al-Fatesh. „Highly Selective Syngas/H2 Production via Partial Oxidation of CH4 Using (Ni, Co and Ni–Co)/ZrO2–Al2O3 Catalysts: Influence of Calcination Temperature“. Processes 7, Nr. 3 (06.03.2019): 141. http://dx.doi.org/10.3390/pr7030141.
Der volle Inhalt der QuelleAnnotation:
In this study, Ni, Co and Ni–Co catalysts supported on binary oxide ZrO2–Al2O3 were synthesized by sol-gel method and characterized by means of various analytical techniques such as XRD, BET, TPR, TPD, TGA, SEM, and TEM. This catalytic system was then tested for syngas respective H2 production via partial oxidation of methane at 700 °C and 800 °C. The influence of calcination temperatures was studied and their impact on catalytic activity and stability was evaluated. It was observed that increasing the calcination temperature from 550 °C to 800 °C and addition of ZrO2 to Al2O3 enhances Ni metal-support interaction. This increases the catalytic activity and sintering resistance. Furthermore, ZrO2 provides higher oxygen storage capacity and stronger Lewis basicity which contributed to coke suppression, eventually leading to a more stable catalyst. It was also observed that, contrary to bimetallic catalysts, monometallic catalysts exhibit higher activity with higher calcination temperature. At the same time, Co and Ni–Co-based catalysts exhibit higher activity than Ni-based catalysts which was not expected. The Co-based catalyst calcined at 800 °C demonstrated excellent stability over 24 h on stream. In general, all catalysts demonstrated high CH4 conversion and exceptionally high selectivity to H2 (~98%) at 700 °C.
24
Yurchenko, Olena, Patrick Diehle, Frank Altmann, Katrin Schmitt und Jürgen Wöllenstein. „Co3O4-Based Materials as Potential Catalysts for Methane Detection in Catalytic Gas Sensors“. Sensors 24, Nr. 8 (18.04.2024): 2599. http://dx.doi.org/10.3390/s24082599.
Der volle Inhalt der QuelleAnnotation:
The present work deals with the development of Co3O4-based catalysts for potential application in catalytic gas sensors for methane (CH4) detection. Among the transition-metal oxide catalysts, Co3O4 exhibits the highest activity in catalytic combustion. Doping Co3O4 with another metal can further improve its catalytic performance. Despite their promising properties, Co3O4 materials have rarely been tested for use in catalytic gas sensors. In our study, the influence of catalyst morphology and Ni doping on the catalytic activity and thermal stability of Co3O4-based catalysts was analyzed by differential calorimetry by measuring the thermal response to 1% CH4. The morphology of two Co3O4 catalysts and two NixCo3−xO4 with a Ni:Co molar ratio of 1:2 and 1:5 was studied using scanning transmission electron microscopy and energy dispersive X-ray analysis. The catalysts were synthesized by (co)precipitation with KOH solution. The investigations showed that Ni doping can improve the catalytic activity of Co3O4 catalysts. The thermal response of Ni-doped catalysts was increased by more than 20% at 400 °C and 450 °C compared to one of the studied Co3O4 oxides. However, the thermal response of the other Co3O4 was even higher than that of NixCo3−xO4 catalysts (8% at 400 °C). Furthermore, the modification of Co3O4 with Ni simultaneously brings stability problems at higher operating temperatures (≥400 °C) due to the observed inhomogeneous Ni distribution in the structure of NixCo3−xO4. In particular, the NixCo3−xO4 with high Ni content (Ni:Co ratio 1:2) showed apparent NiO separation and thus a strong decrease in thermal response of 8% after 24 h of heat treatment at 400 °C. The reaction of the Co3O4 catalysts remained quite stable. Therefore, controlling the structure and morphology of Co3O4 achieved more promising results, demonstrating its applicability as a catalyst for gas sensing.
25
XU, JING, und MARK SAEYS. „COKING MECHANISM AND PROMOTER DESIGN FOR Ni-BASED CATALYSTS: A FIRST PRINCIPLES STUDY“. International Journal of Nanoscience 06, Nr. 02 (April 2007): 131–35. http://dx.doi.org/10.1142/s0219581x07004389.
Der volle Inhalt der QuelleAnnotation:
Based on a first principles study of the interaction of carbon with Ni (111), a new way is proposed to improve the coking resistance of Ni -based catalysts. Three forms of chemisorbed carbon—on-surface carbon atoms, bulk nickel carbide and graphene — are distinguished and their relative stability is studied. At low coverages, on-surface carbon atoms will diffuse to the Ni bulk until saturation at a C:Ni mole fraction of about 1:2. The formation of the carbide will affect the catalytic properties of Ni and might lead to catalyst deactivation. When the on-surface carbon can accumulate to high coverages, formation of a graphene overlayer becomes preferred, leading to surface blocking and catalyst deactivation. Boron was found to be a potential promoter to prevent coking of Ni -based catalysts by effectively blocking the diffusion of carbon into the Ni bulk.
26
Chen, Meng, und Lei Wang. „Performance of Ni-Based Catalysts with La Promoter for the Reforming of Methane in Gasification Process“. Catalysts 14, Nr. 6 (30.05.2024): 355. http://dx.doi.org/10.3390/catal14060355.
Der volle Inhalt der QuelleAnnotation:
The deactivation of active sites caused by high-temperature sintering and the deposition of a large amount of carbon are the main difficulties in the reforming of methane using Ni-based catalysts. La, as a promoter, has an ameliorating effect on the defects of Ni-based catalysts. In this article, the mechanism of action of Ni-based catalysts with the introduction of the rare-earth metal additive La was reviewed, and the effects of La on the methane-reforming performance of Ni-based catalysts were examined. The physical properties, alkalinity, and activity of Ni-based catalysts can be enhanced by the use of the auxiliary agent La, which promotes the conversion of CH4 and CO2 as well as the selectivity towards H2 and CO formation in the reforming of methane. The reason why the Ni-based catalysts could maintain long-term stability in the presence of La was discussed. Furthermore, the current state of research on the introduction of different amounts of La in the reforming of methane at home and abroad was analyzed. It was found that 2–5 wt.% La is the most optimal quantity for improving the catalyst activity and stability, as well as the CO2 chemisorption. The limitations and directions for future research in the reforming of methane were discussed.
27
Zhang, Guoqiang, Jinyu Qin, Yuan Zhou, Huayan Zheng und Fanhui Meng. „Catalytic Performance for CO Methanation over Ni/MCM-41 Catalyst in a Slurry-Bed Reactor“. Catalysts 13, Nr. 3 (16.03.2023): 598. http://dx.doi.org/10.3390/catal13030598.
Der volle Inhalt der QuelleAnnotation:
The Ni-based catalyst has been intensively studied for CO methanation. Here, MCM-41 is selected as support to prepare xNi/MCM-41 catalysts with various Ni contents and the catalytic performance for CO methanation in a slurry-bed reactor is investigated under different reaction conditions. The CO conversion gradually increases as the reaction temperature or pressure rises. As the Ni content increases, the specific surface area and pore volume of xNi/MCM-41 catalysts decrease, the crystallite sizes of metallic Ni increase, while the metal surface area and active Ni atom numbers firstly increase and then slightly decrease. The 20Ni/MCM-41 catalyst with the Ni content of 20 wt% exhibits the highest catalytic activity for CO methanation, and the initial CH4 yield rate is well correlated to the active metallic Ni atom numbers. The characterization of the spent xNi/MCM-41 catalysts shows that the agglomeration of Ni metal is accountable for the catalyst deactivation.
28
Hossain, M. Anwar, Bamidele Victor Ayodele, Chin Kui Cheng und Maksudur R. Khan. „Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported Ni and Co Catalysts: Full Factorial Design Screening“. Bulletin of Chemical Reaction Engineering & Catalysis 13, Nr. 1 (02.04.2018): 57. http://dx.doi.org/10.9767/bcrec.13.1.1197.57-73.
Der volle Inhalt der QuelleAnnotation:
In this study, the potential of dry reforming reaction over CaFe2O4 supported Ni and Co catalysts were investigated. The Co/CaFe2O4 and Ni/CaFe2O4 catalysts were synthesized using wet impregnation method by varying the metal loading from 5-15 %. The synthesized catalysts were tested in methane dry reforming reaction at atmospheric pressure and reaction temperature ranged 700-800 oC. The catalytic performance of the catalysts based on the initial screening is ranked as 5%Co/CaFe2O4 < 10%Co/CaFe2O4 < 5%Ni/CaFe2O4 < 10%Ni/CaFe2O4 according to their performance. The Ni/CaFe2O4 catalyst was selected for further investigation using full factorial design of experiment. The interaction effects of three factors namely metal loading (5-15 %), feed ratio (0.4-1.0), and reaction temperature (700-800 oC) were evaluated on the catalytic activity in terms of CH4 and CO2 conversion as well as H2 and CO yield. The interaction between the factors showed significant effects on the catalyst performance at metal loading, feed ratio and reaction temperature of 15 %, 1.0, and 800 oC. respectively. The 15 wt% Ni/CaFe2O4 was subsequently characterized by Thermogravimetric (TGA), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS), N2-physisorption, Temperature Programmed Desorption (TPD)-NH3, TPD-CO2, and Fourier Transform Infra Red (FTIR) to ascertain its physiochemical properties. This study demonstrated that the CaFe2O4 supported Ni catalyst has a good potential to be used for syngas production via methane dry reforming. Copyright © 2018 BCREC Group. All rights reservedReceived: 5th May 2017; Revised: 8th August 2017; Accepted: 9th August 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Hossain, M.A., Ayodele, B.V., Cheng, C.K., Khan, M.R. (2018). Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported Ni and Co Catalysts: Full Factorial Design Screening. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 57-74 (doi:10.9767/bcrec.13.1.1197.57-74)
29
Wang, Lijian, Kang Zhang, Yi Qiu, Huiyun Chen, Jie Wang und Zhihua Wang. „Catalytic and Sulfur-Tolerant Performance of Bimetallic Ni–Ru Catalysts on HI Decomposition in the Sulfur-Iodine Cycle for Hydrogen Production“. Energies 14, Nr. 24 (17.12.2021): 8539. http://dx.doi.org/10.3390/en14248539.
Der volle Inhalt der QuelleAnnotation:
The sulfur-iodine (SI) cycle holds great promise as an alternative large-scale process for converting water into hydrogen without CO2 emissions. A major issue regarding the long-term stability and activity of the catalysts is their poor sulfur deactivation resistance in the HI feeding process. In this work, the effect of Ru addition for enhancing the activity and sulfur resistance of SiO2-supported Ni catalysts in the HI decomposition reaction has been investigated. The presence of H2SO4 molecules in the HI results in severe sulfur deactivation of the Ru-free Ni/SiO2 catalysts by blocking the active sites. However, Ni–Ru/SiO2 catalysts show higher catalytic activity without sulfur-poisoning by 25% and exhibit more superior catalytic performance than the Ru-free catalyst. The addition of Ru to the Ni/SiO2 catalyst promotes the stability and activity of the catalysts. The experimental trends in activity and sulfur tolerance are consistent with the theoretical modeling, with the catalytic activities existing in the order Ni/SiO2 < Ni–Ru/SiO2. The effect of Ru on the improvement in sulfur resistance over Ni-based catalysts is attributed to electronic factors, as evidenced by theory modeling analysis and detailed characterizations.
30
Hasnan, Nur Shamimie Nadzwin, Manoj Pudukudy, Zahira Yaakob, Nur Hidayatul Nazirah Kamarudin, Kean Long Lim und Sharifah Najiha Timmiati. „Promoting Effects of Copper and Iron on Ni/MSN Catalysts for Methane Decomposition“. Catalysts 13, Nr. 7 (03.07.2023): 1067. http://dx.doi.org/10.3390/catal13071067.
Der volle Inhalt der QuelleAnnotation:
Copper and iron-based bimetallic nickel catalysts supported on Mesostructured Silica Nanoparticles (MSNs) with compositions of 50% Ni–5% Cu/MSN and 50% Ni–5% Fe/MSN were prepared using an impregnation method, and they were compared with a monometallic 50% Ni–MSN catalyst for their activity and stability in methane decomposition reaction. The influence of promoters, such as Cu and Fe, at different reaction temperatures (700 °C, 800 °C and 900 °C) was investigated. The results revealed that the Cu and Fe-promoted catalysts significantly increased the hydrogen yield in methane decomposition compared with the unpromoted catalyst. This could be attributed to the formation of Ni–Cu and Ni–Fe bimetallic alloys in the catalysts, respectively, and this favored the stability of the catalysts. With increasing reaction temperature, the hydrogen yield also increased. However, the hydrogen yield and the lifetime of the nickel catalyst were enhanced upon the addition of iron compared to copper at all the reaction temperatures. The analysis conducted over the spent catalysts validated the formation of multi-walled carbon nanotubes with a bamboo-like internal channel over the catalysts along with a high crystallinity and graphitization degree of the carbon produced.
31
Zou, Jin, De Ping Lu und Qi Jie Zhai. „The Research on Ni-Based Ammonia Decomposition Catalyst“. Applied Mechanics and Materials 644-650 (September 2014): 5364–67. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.5364.
Der volle Inhalt der QuelleAnnotation:
The Ni-based ammonia decomposition catalysts were prepared by vacuum dip-molding, the structures of catalyst carriers and nickel grain were characterized by XRD and SEM. Through three dip-activate technics, the Ni content in catalyst could exceed 6%. The NiO grains bond to each other in vermiform stacks, it is propitious to improve the catalytic activity because of the larger specific area.
32
Song, Da Hye, Un Ho Jung, Young Eun Kim, Hyo Been Im, Tae Ho Lee, Ki Bong Lee und Kee Young Koo. „Influence of Supports on the Catalytic Activity and Coke Resistance of Ni Catalyst in Dry Reforming of Methane“. Catalysts 12, Nr. 2 (14.02.2022): 216. http://dx.doi.org/10.3390/catal12020216.
Der volle Inhalt der QuelleAnnotation:
The dependence of the catalytic activity and coke resistance of Ni-based catalysts on the support type was investigated in the dry reforming of methane (DRM). Catalysts were prepared using incipient wetness impregnation and analyzed using ICP-OES, BET-BJH, XRD, H2-chemisorption, H2-TPR, and CO2-TPD. DRM was performed at 600–750 °C at 144,000 mL/gcat∙h of GHSV (CH4/CO2/N2 = 1/1/1). Ni/Al2O3 and Ni/MgO catalysts formed NiAl2O4 and NiO-MgO solid solutions, respectively, owing to strong binding between the metal and support. In contrast, MgO-Al2O3 and MgAl2O4 supports suppressed NiAl2O4 and NiO-MgO solid solution formation, due to Mg addition, with high metal dispersions of 4.6 and 6.6%, respectively. In the DRM reaction, the Ni/MgO-Al2O3 and Ni/MgAl2O4 catalysts showed high CH4 conversions of 78.1 and 76.8%, respectively, compared with Ni/Al2O3 and Ni/MgO at 750 °C. A stability test was performed at 600 °C for 20 h. A coke study of the spent catalysts was performed using SEM and TGA. Alkaline-earth metal-containing catalysts Ni/MgO-Al2O3 and Ni/MgAl2O4 with strong CO2 adsorption properties showed 20 wt% reduction in carbon deposition compared to commercial catalysts. Therefore, the support and basic properties of the catalyst significantly influenced the catalyst performance and coke resistance in the DRM.
33
Seufitelli, Gabriel V. S., Jason J. W. Park, Phuong N. Tran, Anthony Dichiara, Fernando L. P. Resende und Rick Gustafson. „The Role of Nickel and Brønsted Sites on Ethylene Oligomerization with Ni-H-Beta Catalysts“. Catalysts 12, Nr. 5 (20.05.2022): 565. http://dx.doi.org/10.3390/catal12050565.
Der volle Inhalt der QuelleAnnotation:
The present work studies the adsorption of ethylene on Ni-H-Beta particles to unravel the roles of nickel and Brønsted sites in the catalytic oligomerization of ethylene. Three models (i.e., two based on the Cossee–Arlman mechanism and one based on the metallacycle mechanism) are examined in terms of the nature of the active sites and the adsorption mechanism involved in the ethylene coordination step. The results are consistent with the participation of two active sites in the formation of [Ni(II)-H]+ Cossee–Arlman centers and also suggest that ethylene dissociates upon adsorption on [Ni(II)-H]+ sites. Further characterization of Ni-H-Beta catalysts prepared at different nickel loadings and silica-to-alumina ratios reveals that highly dispersed Ni2+ exists on the catalyst surface and interacts with the catalyst’s lattice oxygen and free NiO crystals. At the same time, the kinetic results indicate that Brønsted sites may form isolated nickel-hydride ([Ni(II)-H]+) centers on the catalyst surface. In addition, the presence of residual, noncoordinated Ni2+ and Brønsted sites (not involved in the formation of [Ni(II)-H]+ sites) shows a reduced probability of the formation of nickel-hydride sites, hindering the conversion rate of ethylene. A mechanism for forming [Ni(II)-H]+ centers is proposed, involving ethylene adsorption over Ni2+ and a Brønsted site. This research has important implications for improving ethylene oligomerization processes over nickel-based heterogeneous catalysts.
34
Frontera, Patrizia, Anastasia Macario, Angela Malara, Saveria Santangelo, Claudia Triolo, Fortunato Crea und Pierluigi Antonucci. „Trimetallic Ni-Based Catalysts over Gadolinia-Doped Ceria for Green Fuel Production“. Catalysts 8, Nr. 10 (02.10.2018): 435. http://dx.doi.org/10.3390/catal8100435.
Der volle Inhalt der QuelleAnnotation:
The present work concerns the characterization of trimetallic nickel catalysts, NiMoRe (Nickel/Molybdenum/Rhenium), NiMoCu (Nickel/Molybdenum/Copper) and NiMoCo (Nickel/Molybdenum/Cobalt), supported on gadolinia-doped ceria and the evaluation of their catalytic performance in the auto-thermal reforming of ethanol to hydrogen. Catalysts have been prepared by wet impregnation and characterized by XRD, SEM-EDX, TG-DSC, TEM, CHNS, H2-TPR and micro-Raman spectroscopy. The resistance of Ni-alloy catalysts to the carbon deposition and sulfur poisoning has been studied. All catalysts show a similar behavior in the auto-thermal reforming reaction: 100% of ethanol conversion and high selectivity to syngas products, up to 77 vol.%. At 800 °C the coke deposition is very low (less than 0.34 wt%). Sulfur content affects the selectivity and the activity of the catalysts, especially towards the coke formation: high sulfur content promotes the ethylene formation, therefore the amount of coke deposited on spent catalyst increases. NiMoCu seems to be the trimetallic catalyst less sensitive to this aspect.
35
Meshkini Far, Reza, Olena V. Ischenko, Alla G. Dyachenko, Oleksandr Bieda, Snezhana V. Gaidai und Vladyslav V. Lisnyak. „CO2 hydrogenation into CH4 over Ni–Fe catalysts“. Functional Materials Letters 11, Nr. 03 (Juni 2018): 1850057. http://dx.doi.org/10.1142/s1793604718500571.
Der volle Inhalt der QuelleAnnotation:
Here, we report, for the first time, on the catalytic hydrogenation of CO2 to methane at atmospheric pressure. For the preparation of hydrogenation catalysts based on Ni and Fe metals, a convenient method is developed. According to this method, low-temperature reduction of the co-precipitated Ni and Fe oxides with hydrogen gives the effective and selective bimetallic Ni[Formula: see text]Fe[Formula: see text], Ni[Formula: see text]Fe[Formula: see text] and Ni[Formula: see text]Fe[Formula: see text] catalysts. At the temperature range of 300–400[Formula: see text]C, they exhibit a high efficiency of CH4 production with respect to monometallic Ni and Fe catalysts. The results imply a synergistic effect between Ni and Fe which caused the superior activity of the Ni[Formula: see text]Fe[Formula: see text] catalyst conversing [Formula: see text]% of CO2 into CH4 at 350[Formula: see text]C. To adapt the Ni–Fe catalysts in the industry, the effect of two different carriers on the efficiency of the alumina-supported Ni[Formula: see text]Fe[Formula: see text] catalyst was investigated. It is found that the Ni[Formula: see text]Fe[Formula: see text]/[Formula: see text]-Al2O3 catalyst effectively conversed CO2 giving 100% methane yield already at 275[Formula: see text]C.
36
Tsiotsias, Anastasios I., Nikolaos D. Charisiou, Ioannis V. Yentekakis und Maria A. Goula. „Bimetallic Ni-Based Catalysts for CO2 Methanation: A Review“. Nanomaterials 11, Nr. 1 (24.12.2020): 28. http://dx.doi.org/10.3390/nano11010028.
Der volle Inhalt der QuelleAnnotation:
CO2 methanation has recently emerged as a process that targets the reduction in anthropogenic CO2 emissions, via the conversion of CO2 captured from point and mobile sources, as well as H2 produced from renewables into CH4. Ni, among the early transition metals, as well as Ru and Rh, among the noble metals, have been known to be among the most active methanation catalysts, with Ni being favoured due to its low cost and high natural abundance. However, insufficient low-temperature activity, low dispersion and reducibility, as well as nanoparticle sintering are some of the main drawbacks when using Ni-based catalysts. Such problems can be partly overcome via the introduction of a second transition metal (e.g., Fe, Co) or a noble metal (e.g., Ru, Rh, Pt, Pd and Re) in Ni-based catalysts. Through Ni-M alloy formation, or the intricate synergy between two adjacent metallic phases, new high-performing and low-cost methanation catalysts can be obtained. This review summarizes and critically discusses recent progress made in the field of bimetallic Ni-M (M = Fe, Co, Cu, Ru, Rh, Pt, Pd, Re)-based catalyst development for the CO2 methanation reaction.
37
Duisembiyev, M. Zh. „Production of tetrahydrofurfuryl alcohol by hydrogenation of furfuryl using an aluminumnickel alloy catalyst“. BULLETIN of the L.N. Gumilyov Eurasian National University. Chemistry. Geography. Ecology Series 138, Nr. 1 (2022): 24–30. http://dx.doi.org/10.32523/2616-6771-2022-138-1-24-30.
Der volle Inhalt der QuelleAnnotation:
Alkalized catalysts significantly affect the activity of furfural hydrogenation catalysts based on a complex of X-ray diffraction studies based on a complex of X-ray diffraction studies. The skeletal nickel catalyst and the aluminum-nickel alloy catalyst are complex multicomponent systems consisting of impurity oxides and intermetallic compounds.Thus, when metals are introduced into Ni-Al catalysts, zirconium, niobium, molybdenum, chromium, and copper alloys have a significant effect on the phase composition, structure, and aspect ratio of skeletal nickel catalysts. In an aluminum-nickel alloy catalyst, additives other than the usual Ni-Al (50-50) -NiAl3, Ni2Al3 and eutectic (NiAl3 + Al) phases form new, yet unknown Fx-phases. In addition to skeletal nickel catalysts, the catalysts consist of additives Y-Al2O3, Ni2Al3 and Fx.Doped aluminum-nickel compounds do not affect the parameters of the nickel crystal lattices, however, they significantly crush the catalyst crystals (L) and increase the specific areaof the catalyst by 95.0-128.5 m2/g.
38
Liu, Xingmin, Wenjie Xie, Marc Widenmeyer, Hui Ding, Guoxing Chen, Dario M. De Carolis, Kerstin Lakus-Wollny, Leopoldo Molina-Luna, Ralf Riedel und Anke Weidenkaff. „Upcycling Waste Plastics into Multi-Walled Carbon Nanotube Composites via NiCo2O4 Catalytic Pyrolysis“. Catalysts 11, Nr. 11 (11.11.2021): 1353. http://dx.doi.org/10.3390/catal11111353.
Der volle Inhalt der QuelleAnnotation:
In this work, multi-walled carbon nanotube composites (MWCNCs) were produced by catalytic pyrolysis of post-consumer plastics with aluminium oxide-supported nickel, cobalt, and their bimetallic (Ni/α–Al2O3, Co/α–Al2O3, and NiCo/α–Al2O3) oxide-based catalysts. The influence of catalyst composition and catalytic reaction temperature on the carbon yield and structure of CNCs were investigated. Different temperatures (800, 900, 950, and 1000 °C) and catalyst compositions (Ni, Co, and Ni/Co) were explored to maximize the yield of carbon deposited on the catalyst. The obtained results showed that at the same catalytic temperature (900 °C), a Ni/Co bimetallic catalyst exhibited higher carbon yield than the individual monometallic catalysts due to a better cracking capability on carbon-hydrogen bonds. With the increase of temperature, the carbon yield of the Ni/Co bimetallic catalyst increased first and then decreased. At a temperature of 950 °C, the Ni/Co bimetallic catalyst achieved its largest carbon yield, which can reach 255 mg g−1plastic. The growth of CNCs followed a “particle-wire-tube” mechanism for all studied catalysts. This work finds the potential application of complex oxide composite material catalysts for the generation of CNCs in catalytic pyrolysis of wasted plastic.
39
Khan, Wasim Ullah, Anis Hamza Fakeeha, Ahmed Sadeq Al-Fatish, Muhammad Awais Naeem, Ahmed Ibrahim Aidid und Ahmed Elhag Abasaeed. „Catalytic Decomposition of Methane over La2O3 Supported Mono- and Bimetallic Catalysts“. Applied Mechanics and Materials 625 (September 2014): 275–79. http://dx.doi.org/10.4028/www.scientific.net/amm.625.275.
Der volle Inhalt der QuelleAnnotation:
Catalytic decomposition of methane was investigated over nickel and cobalt based mono-and bimetallic catalysts for the production of hydrogen and filamentous carbon. Catalysts with different Ni to Co ratios supported on La2O3were prepared by co-precipitation method. The activity test and characterization results revealed that the catalyst containing 15wt% Ni and 10wt% Co over La2O3support presented relatively better catalytic performance among all the tested catalyst. The catalysts were characterized by BET, TGA and temperature programmed reduction (TPR).
40
Zhang, Chengyang, Renkun Zhang, Hui Liu, Qinhong Wei, Dandan Gong, Liuye Mo, Hengcong Tao, Sha Cui und Luhui Wang. „One-Step Synthesis of Highly Dispersed and Stable Ni Nanoparticles Confined by CeO2 on SiO2 for Dry Reforming of Methane“. Energies 13, Nr. 22 (15.11.2020): 5956. http://dx.doi.org/10.3390/en13225956.
Der volle Inhalt der QuelleAnnotation:
Sintering and carbon deposition are the two main ways to deactivate Ni-based catalysts during methane reforming. Herein, a stable Ni-CeO2/SiO2(CSC) catalyst was prepared by a one-step colloidal solution combustion method (CSC) and used for dry reforming of methane. In the catalyst, the small Ni particles were confined by CeO2 particles and highly dispersed on the surface of SiO2, forming a spatial confinement structure with a rich Ni-CeO2 interface in the catalyst. The Ni-CeO2/SiO2(CSC) catalyst prepared by the one-step CSC method exhibited superior activity at 700 °C during dry reforming of methane, and the performance of the catalyst was stable after 20 h of reaction with only a small amount of carbon deposition present (1.8%). Due to the spatial confinement effect, Ni was stable and less than 5 nm during reaction. The small Ni particle size and rich Ni-CeO2 interface reduced the rate of carbon deposition. This colloidal combustion method could be applied to prepare stable metal-based catalysts with rich metal–oxide interfaces for high-temperature reactions.
41
Li, Luming, Song Wu, Hongmei Li, Jie Deng und Junshan Li. „Preparation of Novel Mesoporous LaFeO3-SBA-15-CTA Support for Syngas Formation of Dry Reforming“. Nanomaterials 12, Nr. 9 (24.04.2022): 1451. http://dx.doi.org/10.3390/nano12091451.
Der volle Inhalt der QuelleAnnotation:
A nanocomposite NiPt/5LSBA-160 catalyst comprised of highly dispersed Ni nanoparticles contacting intimately with Pt over novel mesoporous LaFeO3-SBA-15-CTA support with a high specific surface area (SSA) was successfully developed for the dry reforming of methane. Results revealed that the high SSA mesoporous LaFeO3-SBA-15-CTA materials could first be synthesized by an in situ growth hydrothermal process and used as an excellent carrier candidate of Ni-based catalysts to achieve enhanced catalytic activity due to the strong interaction between LaFeO3 and Ni species. Moreover, the introduction of Pt over a Ni/5LSBA-160 catalyst would further promote the interaction between Ni and support, improve the dispersion of active Ni centers and obtain a higher syngas formation rate as well as tolerance to carbon coking than that of a Pt-free Ni/5LSBA-160 catalyst sample. This finding uncovers a promising prospect for high SSA mesoporous perovskite preparation and utilization in catalysis such as oxidation, hydrogenation, photocatalysis, energy conversion and so on.
42
Li, Luming, Song Wu, Hongmei Li, Jie Deng und Junshan Li. „Preparation of Novel Mesoporous LaFeO3-SBA-15-CTA Support for Syngas Formation of Dry Reforming“. Nanomaterials 12, Nr. 9 (24.04.2022): 1451. http://dx.doi.org/10.3390/nano12091451.
Der volle Inhalt der QuelleAnnotation:
A nanocomposite NiPt/5LSBA-160 catalyst comprised of highly dispersed Ni nanoparticles contacting intimately with Pt over novel mesoporous LaFeO3-SBA-15-CTA support with a high specific surface area (SSA) was successfully developed for the dry reforming of methane. Results revealed that the high SSA mesoporous LaFeO3-SBA-15-CTA materials could first be synthesized by an in situ growth hydrothermal process and used as an excellent carrier candidate of Ni-based catalysts to achieve enhanced catalytic activity due to the strong interaction between LaFeO3 and Ni species. Moreover, the introduction of Pt over a Ni/5LSBA-160 catalyst would further promote the interaction between Ni and support, improve the dispersion of active Ni centers and obtain a higher syngas formation rate as well as tolerance to carbon coking than that of a Pt-free Ni/5LSBA-160 catalyst sample. This finding uncovers a promising prospect for high SSA mesoporous perovskite preparation and utilization in catalysis such as oxidation, hydrogenation, photocatalysis, energy conversion and so on.
43
Zhou, Long, Li Ping Ma, Ze Cheng Zi, Jun Ma und Jian Tao Chen. „Study on Ni Catalytic Hydrogenation of Carbon Dioxide for Methane“. Applied Mechanics and Materials 628 (September 2014): 16–19. http://dx.doi.org/10.4028/www.scientific.net/amm.628.16.
Der volle Inhalt der QuelleAnnotation:
Catalyst by different carriers prepared of carbon dioxide conversion sequence is: Ni/TiO2> Ni/γ-Al2O3> Ni/MgO > Ni/SiO2. Second metal, Co, Mn, Cu, La and Ce, was significantly enhanced the activity of methanation nickel-based catalysts in the carbon dioxide methanation reaction, but second metal of Cu was bad for the activity of methanation. The 10%Ni/Al2O3 and 2.5%Ce-10%Ni/Al2O3 catalysts were characterized by TG and H2-TPR，it was revealed to Ce which is benefit for reduce NiO reduction temperature and the optimal reduction temperature of the catalysts in between 400°C and 500 °C
44
Suksumrit, Kamonrat, Christoph A. Hauzenberger, Srett Santitharangkun und Susanne Lux. „Reduced Siderite Ore Combined with Magnesium Oxide as Support Material for Ni-Based Catalysts; An Experimental Study on CO2 Methanation“. Catalysts 14, Nr. 3 (20.03.2024): 206. http://dx.doi.org/10.3390/catal14030206.
Der volle Inhalt der QuelleAnnotation:
Ni-based catalysts play a fundamental role in catalytic CO2 methanation. In this study, the possibility of using siderite ore as a catalyst or catalytic support material for nickel-based catalysts was investigated, aiming at the exploitation of an abundant natural resource. The catalytic performance of Ni-based catalysts with reduced siderite ore as a support was evaluated and compared to MgO as a support material. MgO is known as an effective support material, as it provides access to bifunctional catalysts because of its basicity and high CO2 adsorption capacity. It was shown that undoped and Ni-doped reduced siderite ore have comparable catalytic activity for CO2 hydrogenation (20−23%) at 648 K, but show limited selectivity toward methane (<20% for sideritereduced and 60.2% for Ni/sideritereduced). When MgO was added to the support material (Ni/sideritereduced/MgO), both the CO2 conversion and the selectivity toward methane increased significantly. CO2 conversions were close to the thermodynamic equilibrium, and methane selectivities of ≥99% were achieved.
45
Wang, Luhui, Junang Hu, Hui Liu, Qinhong Wei, Dandan Gong, Liuye Mo, Hengcong Tao und Chengyang Zhang. „Three-Dimensional Mesoporous Ni-CeO2 Catalysts with Ni Embedded in the Pore Walls for CO2 Methanation“. Catalysts 10, Nr. 5 (08.05.2020): 523. http://dx.doi.org/10.3390/catal10050523.
Der volle Inhalt der QuelleAnnotation:
Mesoporous Ni-based catalysts with Ni confined in nanochannels are widely used in CO2 methanation. However, when Ni loadings are high, the nanochannels are easily blocked by nickel particles, which reduces the catalytic performance. In this work, three-dimensional mesoporous Ni-CeO2-CSC catalysts with high Ni loadings (20−80 wt %) were prepared using a colloidal solution combustion method, and characterized by nitrogen adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM) and H2 temperature programmed reduction (H2-TPR). Among the catalysts with different Ni loadings, the 50% Ni-CeO2-CSC with 50 wt % Ni loading exhibited the best catalytic performance in CO2 methanation. Furthermore, the 50% Ni-CeO2-CSC catalyst was stable for 50 h at 300° and 350 °C in CO2 methanation. The characterization results illustrate that the 50% Ni-CeO2-CSC catalyst has Ni particles smaller than 5 nm embedded in the pore walls, and the Ni particles interact with CeO2. On the contrary, the 50% Ni-CeO2-CP catalyst, prepared using the traditional coprecipitation method, is less active and selective for CO2 methanation due to the larger size of the Ni and CeO2 particles. The special three-dimensional mesoporous embedded structure in the 50% Ni-CeO2-CSC can provide more metal–oxide interface and stabilize small Ni particles in pore walls, which makes the catalyst more active and stable in CO2 methanation.
46
Feng, Yanyan, Wen Yang und Wei Chu. „A Study of CO2Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics“. International Journal of Chemical Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/795386.
Der volle Inhalt der QuelleAnnotation:
This work studied the influence of textural characteristics of CNTs on catalytic performance of Ni/CNTs for CO2methanation. The CNTs supports were prepared by chemical vapor deposition method using Ni/MgO catalysts, and acetonitrile and ethanol were used as carbon sources, respectively. The Ni/CNTs catalysts were prepared via impregnation method and characterized by X-ray diffraction (XRD), N2adsorption/desorption, and temperature-programmed reduction (H2-TPR) techniques. The results indicated that the textural characteristics of CNTs supports significantly impacted on the catalytic performance of Ni/CNTs. The catalyst Ni/CNTs-E (CNTs using ethanol as carbon source) had good reducibility, high specific surface area, and moderate defects, resulting in higher CO2conversion and CH4yield, followed by Ni/CNTs-C (commercial CNTs) and Ni/CNTs-A (CNTs using acetonitrile as carbon source). Based on Arrhenius formula, activation energies of the catalysts were calculated and were found decreased for Ni/CNTs-A and Ni/CNTs-E.
47
Zhang, Jianguang, und Ningge Xu. „Hydrogen Production from Ethylene Glycol Aqueous Phase Reforming over Ni–Al Layered Hydrotalcite-Derived Catalysts“. Catalysts 10, Nr. 1 (01.01.2020): 54. http://dx.doi.org/10.3390/catal10010054.
Der volle Inhalt der QuelleAnnotation:
By introducing Mg, Cu, Zn, Sn, and Mn into the synthesis processes of Ni and Al based hydrotalcite, Ni–Al layered hydrotalcite-derived catalysts with different metal compositions were prepared. In this paper, the effect of metal composition on the structure of Ni–Al layered hydrotalcite-derived catalysts is investigated, and then catalytic activities of prepared catalysts with different metal compositions on ethylene glycol aqueous-phase reforming are analyzed. The physicochemical properties of the Ni–Al layered hydrotalcite-derived catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and nitrogen adsorption–desorption technology. The obtained hydrotalcite-derived catalysts were applied to the process of ethylene glycol aqueous-phase reforming (APR). The XRD results confirmed that the precursors of hydrotalcite-derived catalysts with metal compositions of Ni/Mg/Al, Ni/Cu/Al, Ni/Zn/Al, and Ni/Sn/Al had hydrotalcite crystalloid morphology. During the process of ethylene glycol aqueous phase reforming, all the catalysts showed high conversion of ethylene glycol (>90%), and the optimum hydrogen yield (73.5%) was obtained when using the catalyst with metal composition of Ni/Mg/Al at 225 °C under 2.6 MPa in nitrogen atmosphere for 2.5 h.
48
Zhao, Ming, Liang Zhao, Xiao-Yan Zhao, Jing-Pei Cao und Koh-ichi Maruyama. „Pd-Based Nano-Catalysts Promote Biomass Lignin Conversion into Value-Added Chemicals“. Materials 16, Nr. 14 (24.07.2023): 5198. http://dx.doi.org/10.3390/ma16145198.
Der volle Inhalt der QuelleAnnotation:
Lignin, as a structurally complex biomaterial, offers a valuable resource for the production of aromatic chemicals; however, its selective conversion into desired products remains a challenging task. In this study, we prepared three types of Pd-based nano-catalysts and explored their application in the depolymerization of alkali lignin, under both H2-free (hydrogen transfer) conditions and H2 atmosphere conditions. The materials were well characterized with TEM, XRD, and XPS and others, and the electronic interactions among Pd, Ni, and P were analyzed. The results of lignin depolymerization experiments revealed that the ternary Pd-Ni-P catalyst exhibited remarkable performance and guaiacols could be produced under H2 atmosphere conditions in 14.2 wt.% yield with a selectivity of 89%. In contrast, Pd-Ni and Pd-P catalysts resulted in a dispersed product distribution. Considering the incorporation of P and the Pd-Ni synergistic effect in the Pd-Ni-P catalyst, a possible water-involved transformation route of lignin depolymerization was proposed. This work indicates that metal phosphides could be promising catalysts for the conversion of lignin and lignin-derived feedstocks into value-added chemicals.
49
Wei, Minghui, und Xuerong Shi. „Research Progress on Stability Control on Ni-Based Catalysts for Methane Dry Reforming“. Methane 3, Nr. 1 (06.02.2024): 86–102. http://dx.doi.org/10.3390/methane3010006.
Der volle Inhalt der QuelleAnnotation:
CO2 reforming of CH4 (DRM) utilizes the greenhouse gases of CH4 and CO2 to obtain the synthesis gas, benefiting the achievement of carbon neutrality. However, the deactivation of Ni-based catalysts caused by sintering and carbon deposition limits the industrial application. Focusing on stability improvement, this review first summarizes the reaction mechanism and deactivation mechanism in DRM and then discusses the impact of catalyst active components, supports, and interfacial structure. Finally, we propose the design direction of stable Ni-based catalysts towards DRM, providing guidance for the future development of catalysts suitable for industrial production.
50
Sanz-Martínez, Andrés, Paul Durán, Víctor D. Mercader, Eva Francés, José Ángel Peña und Javier Herguido. „Biogas Upgrading by CO2 Methanation with Ni-, Ni–Fe-, and Ru-Based Catalysts“. Catalysts 12, Nr. 12 (08.12.2022): 1609. http://dx.doi.org/10.3390/catal12121609.
Der volle Inhalt der QuelleAnnotation:
This piece of work dealt with the concept of ‘biogas upgrading’ or enrichment of the CH4 contained in a sweetened biogas to proportions and features comparable to those of synthetic natural gas (SNG). For this, the behavior of three lab made catalysts (Ni/Al2O3, Ru/Al2O3, and Ni–Fe/Al2O3) was tested in a CO2 methanation reaction (Sabatier reaction) under different feeding conditions (with and without methane). In the first set of experiments (without methane), the good catalytic behavior of the solids was validated. All three catalysts offered similar and increasing CO2 conversions with increasing temperature (range studied from 250 to 400 °C) at a constant WHSV of 30 × 103 STPmL·gcat−1·h−1. The CH4 selectivity remained close to one in all cases. Considering their total metallic load, the Ru (3.7 wt%)-based catalyst stood out remarkably, with TOF values that reached up to 5.1 min−1, this being six or three times higher, than those obtained with the Ni (10.3 wt%) and Ni–Fe (7.4–2.1 wt%) catalysts, respectively. In the second set (cofeeding methane), and also for the three catalysts, a high correspondence between the conversions (and selectivities) obtained with both types of feeds was observed. This indicated that the addition of CH4 to the system did not severely modify the reaction mechanism, resulting in the possibility of taking advantage of the ‘biogas upgrading’ process by using H2 produced off-peak by electrolysis. In order to maximize the CH4 yield, temperatures in the range from 350–375 °C and a H2:CO2 molar ratio of 6:1 were determined as the optimal reaction conditions.