Journal articles: 'Co based hydroxides'

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Balram, Anirudh, Jie Chao Jiang, Moisés Hernández Fernández, and Dennis De Sheng Meng. "Nickel-Cobalt Double Hydroxide Decorated Carbon Nanotubes via Aqueous Electrophoretic Deposition towards Catalytic Glucose Detection." Key Engineering Materials 654 (July 2015): 70–75. http://dx.doi.org/10.4028/www.scientific.net/kem.654.70.

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In this work, we present a facile technique based on electrophoretic deposition (EPD) to produce transition metal hydroxide decorated carbon nanotubes (CNT) for electrochemical applications. We specifically explore the performance of nickel-cobalt hydroxides given their high activity, conductivity and stability as compared to the individual hydroxides. We exploit the high local pH at the negative electrodes during water-based EPD to form nanoparticles of nickel-cobalt hydroxides in situ on the CNT surface. We focus our work here on obtaining functional and conductive deposits on CNTs. The hydrophilic binderless deposits of Ni-Co double hydroxide decorated CNTs obtained here are used for non-enzymatic glucose detection. XPS data and electrochemical testing reveal difference in the deposited double hydroxide based on chronology of charging salt addition even at the same ratio. When cobalt and nickel salts are sequentially added at a ratio of 1:1, the deposited double hydroxides show excellent glucose sensitivity of ~3300μA/mM.cm2 at applied potential of 0.55V vs. Ag/AgCl reference electrode.

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Cysewska, Karolina, Maria Krystyna Rybarczyk, Grzegorz Cempura, Jakub Karczewski, Marcin Łapiński, Piotr Jasinski, and Sebastian Molin. "The Influence of the Electrodeposition Parameters on the Properties of Mn-Co-Based Nanofilms as Anode Materials for Alkaline Electrolysers." Materials 13, no. 11 (June 11, 2020): 2662. http://dx.doi.org/10.3390/ma13112662.

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In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a β-phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2·g−1, a pore volume of 0.0042 cm3·g−1, and high electrochemical stability with an overpotential deviation around 330–340 mV at 10 mA·cm−2geo for 70 h.

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He, Peng Cheng, Xiao Bo Ji, Qing Zhang, Yi Fei Liu, and Wen Cong Lu. "Shape-Controlled Synthesis and Pattern Recognition of Core-Shell Co-Al Hydroxides Superstructures." Advanced Materials Research 1120-1121 (July 2015): 188–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.188.

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In this paper, the optimal projection recognition (OPR) developed in our lab has been used to find the regularities of forming core-shell Co-Al Hydroxides superstructures.The criteria for predicting core-shell Co-Al Hydroxides superstructures can be obtained by using OPR method among different kinds of pattern recognition diagrams. The new samples predicted to be core-shell Co-Al Hydroxides superstructures were designed by using the inverse projection based on the OPR method. The predicted results agreed well with our experiments. Therefore, the work presented is very useful in the shape-controlled synthesis of core-shell Co-Al Hydroxides superstructures.

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Xie, Yu-Long, Fa-Ping Ye, and Su-Qin Zhao. "Preparation of magnetic Co–Fe layered double hydroxides and its adsorption properties for the removal of methyl orange." Journal of Chemical Research 47, no. 1 (January 2023): 174751982211503. http://dx.doi.org/10.1177/17475198221150382.

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In this study, Co–Fe layered double hydroxides are prepared by a hydrothermal method. The Co–Fe layered double hydroxides are used as an adsorbent for the investigation of the thermodynamic parameters and adsorption kinetics of methyl orange from aqueous solution. The results show that adsorption is affected by adsorbent dosage, adsorption time, and temperature. The characteristics of samples are investigated using X-ray powder diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and N2 adsorption–desorption isotherms. The adsorption saturation level of Co–Fe layered double hydroxides on methyl orange is studied, with the results showing that the maximum uptake capacity for methyl orange is 10.21 mg g−1 based on Co–Fe layered double hydroxides. The adsorption kinetics of methyl orange is consistent with the Temkin isotherm equation and quasi-secondary kinetic model. Furthermore, separation is easily accomplished under the action of an applied magnetic field. The prepared Co–Fe layered double hydroxides can be applied as an effective adsorbent for decontamination of anionic dyes in industrial effluents.

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Buffet, Jean-Charles, Zoë R. Turner, Robert T. Cooper, and Dermot O'Hare. "Ethylene polymerisation using solid catalysts based on layered double hydroxides." Polymer Chemistry 6, no. 13 (2015): 2493–503. http://dx.doi.org/10.1039/c4py01742k.

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We report here the use of methylaluminoxane (MAO) modified aqueous miscible organic solvent treated (AMOST) layered double hydroxide, Mg₆Al₂(OH)₁₆CO₃·4H₂O (AMO-Mg₃Al-CO₃) as a catalyst support system for the slurry phase polymerisation of ethylene using immobilised metallocene and non-metallocene metal complexes.

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Cui, Yan, Yuan Xue, Rui Zhang, Jian Zhang, Xing'ao Li, and Xinbao Zhu. "Vanadium–cobalt oxyhydroxide shows ultralow overpotential for the oxygen evolution reaction." Journal of Materials Chemistry A 7, no. 38 (2019): 21911–17. http://dx.doi.org/10.1039/c9ta07918a.

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Palapa, Neza Rahayu, Bakri Rio Rahayu, Tarmizi Taher, Aldes Lesbani, and Risfidian Mohadi. "Kinetic Adsorption of Direct Yellow Onto Zn/Al and Zn/Fe Layered Double Hydroxides." Science and Technology Indonesia 4, no. 4 (October 29, 2019): 101. http://dx.doi.org/10.26554/sti.2019.4.4.101-104.

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Zn/Al and Zn/Fe layered double hydroxides has successfully synthesized by co-precipitation methods with molar ration 3:1. The samples were characterized using X-Ray Diffraction, Fourier Transform Infrared Spectroscopy and Surface Area using BET method. In this study, Zn/Al and Zn/Fe layered double hydroxides were used to remove direct yellow dye in aqueous solution. The experiments were carried out time variations with the aim of observing the kinetic studies. The results showed that the adsorption of direct yellow onto Zn/Al and Zn/Fe layered double hydroxides based on co-efficient correlation kinetic models more fit using pseudo-second-order than pseudo-first-order.

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Kovalenko, Vadym, and Valerii Kotok. "The determination of synthesis conditions and color properties of pigments based on layered double hydroxides with Co as a guest cation." Eastern-European Journal of Enterprise Technologies 6, no. 6 (114) (December 21, 2021): 32–38. http://dx.doi.org/10.15587/1729-4061.2021.247160.

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Nail polish, in particular gel polish, is the most commonly used cosmetic product. A component of the gel polish, which determines the consumer color characteristics of the gel polish. Layered double hydroxides (LDH) are promising pigments. To expand the range of colors and shades of pigments, the use of LDH with colored host and guest cations is promising. The parameters of synthesis and color characteristics of samples of Zn-Co and Cu-Co hydroxide pigments were studied. To obtain LDH with Co as a guest cation in the synthesis, the conversion of cobalt to the trivalent state was carried out at a temperature of 80 °C using oxidation with atmospheric oxygen or sodium hypochlorite. The oxidation efficiency was evaluated by X-ray phase analysis by the presence or absence of cobalt-containing phases. The color characteristics of the synthesized pigment samples were studied by spectroscopic measurement and calculation in RGB, CIELab, and LCH color models. The low efficiency of cobalt oxidation at the moment of Zn-Co LDH synthesis with atmospheric oxygen at an elevated synthesis temperature of 80 °C was shown, while cobalt was released as a separate Co3O4 phase. A higher efficiency of cobalt oxidation at the moment of synthesis using sodium hypochlorite with the formation of Zn-Co LDH was revealed. It is recommended to use the hypochlorite oxidation of Co2+ to Co3+ in the LDH synthesis with Co in the form of a guest cation. The formation of a separate phase of zinc oxide was found in both types of oxidation due to the thermal decomposition of zinc hydroxide. Comparative analysis of color characteristics showed that all samples have a brown color of different saturation. It was revealed that during the formation of Co-containing LDH, the lightness of the color decreases. Color saturation increases in the case of a colored host cation, such as Cu.

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XIANG, X., L. ZHANG, H. HIMA, F. LI, and D. EVANS. "Co-based catalysts from Co/Fe/Al layered double hydroxides for preparation of carbon nanotubes." Applied Clay Science 42, no. 3-4 (January 2009): 405–9. http://dx.doi.org/10.1016/j.clay.2008.04.004.

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Tian, Jing, Weixin Qian, Haitao Zhang, Hongfang Ma, and Weiyong Ying. "Synthesis of methanol over highly dispersed Cu–Fe based catalysts derived from layered double hydroxides." RSC Advances 13, no. 20 (2023): 13902–10. http://dx.doi.org/10.1039/d3ra01188g.

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In this paper, catalysts with different aluminum contents were prepared by a co-precipitation method using LDHs (layered double hydroxides) as the precursors through the adjustment of Cu2+ : Fe2+, and the catalysts were named LDO catalysts.

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Cao, Xueying, Ying Liu, Yuxue Zhong, Liang Cui, Aitang Zhang, Joselito M. Razal, Wenrong Yang, and Jingquan Liu. "Flexible coaxial fiber-shaped asymmetric supercapacitors based on manganese, nickel co-substituted cobalt carbonate hydroxides." Journal of Materials Chemistry A 8, no. 4 (2020): 1837–48. http://dx.doi.org/10.1039/c9ta11942f.

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A wearable coaxial fiber-shaped asymmetric supercapacitor based on well-aligned Mn, Ni co-substituted Co carbonate hydroxide nanoneedle arrays on carbon fibers is successfully fabricated, and it exhibits excellent electrochemical performances.

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12

Zhai, Mengyi, Jihui Zhao, Dongmin Wang, Xuan Gao, Qibao Wang, Zhangheng Li, and Ming Zhang. "Layered double hydroxides (LDHs) modified cement-based materials: A systematic review." Nanotechnology Reviews 11, no. 1 (January 1, 2022): 2857–74. http://dx.doi.org/10.1515/ntrev-2022-0478.

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Abstract Ion erosion and carbonization in concrete are the key factors leading to the deterioration of durability. Layered double hydroxides (LDHs) are a kind of functional material with layered structures and ion exchange properties, which can capture a variety of harmful anions in concrete pore solutions. Therefore, LDHs exhibit great potential in improving the durability of concrete as new modified material. This article reviews the recent progress of LDHs. Based on the structural characteristics of LDHs, this work discusses the binding effect of LDHs on Cl−, SO 4 2 − {\text{SO}}_{4}^{2-} , and CO 3 2 − {\text{CO}}_{3}^{2-} in cement-based materials. We also analyze the influence of LDHs on the physical, mechanical, and hydration properties of cement-based materials and describe the modification mechanisms. Further, the improved durability of concrete and the corrosion inhibition of reinforcement by LDHs were summarized. Finally, we briefly point out some problems in the current research and development trends in the future on LDHs modified cement-based materials.

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Yong, Jesus David, Ricardo Valdez, Miguel Ángel Armenta, Noé Arjona, Georgina Pina-Luis, and Amelia Olivas. "Influence of Co²⁺, Cu²⁺, Ni²⁺, Zn²⁺, and Ga³⁺ on the iron-based trimetallic layered double hydroxides for water oxidation." RSC Advances 12, no. 26 (2022): 16955–65. http://dx.doi.org/10.1039/d2ra01980a.

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14

Saber, Osama, Sajid Ali Ansari, Aya Osama, and Mostafa Osama. "One-Dimensional Nanoscale Si/Co Based on Layered Double Hydroxides towards Electrochemical Supercapacitor Electrodes." Nanomaterials 12, no. 9 (April 20, 2022): 1404. http://dx.doi.org/10.3390/nano12091404.

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It is well known that layered double hydroxides (LDHs) are two-dimensional (2D) layered compounds. However, we modified these 2D layered compounds to become one-dimensional (1D) nanostructures destined for high-performance supercapacitors applications. In this direction, silicon was inserted inside the nanolayers of Co-LDHs producing nanofibers of Si/Co LDHs through the intercalation of cyanate anions as pillars for building nanolayered structures. Additionally, nanoparticles were observed by controlling the preparation conditions and the silicon percentage. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermal analyses have been used to characterize the nanolayered structures of Si/Co LDHs. The electrochemical characterization was performed by cyclic voltammetry and galvanic charge–discharge technique in 2M KOH electrolyte solution using three-electrode cell system. The calculated specific capacitance results indicated that the change of morphology from nanoparticles or plates to nanofibers had a positive effect for improving the performance of specific capacitance of Si/Co LDHs. The specific capacitance enhanced to be 621.5 F g−1 in the case of the nanofiber of Si/Co LDHs. Similarly, the excellent cyclic stability (84.5%) was observed for the nanofiber. These results were explained through the attribute of the nanofibrous morphology and synergistic effects between the electric double layer capacitive character of the silicon and the pseudo capacitance nature of the cobalt. The high capacitance of ternary Si/Co/cyanate LDHs nanocomposites was suggested to be used as active electrode materials for high-performance supercapacitors applications.

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Nestroinaia, Olga, and Oksana Ponomarenko. "Synthesis of hybrid materials based on layered double hydroxides." Chemical Bulletin of Kazakh National University, no. 2 (June 29, 2019): 4–10. http://dx.doi.org/10.15328/cb1025.

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The use of pesticides adversely affects not only the environment, but also human health. A promising direction in solving this problem is to obtain hybrid materials capable of controlled release of pesticides. Layered double hydroxides (LDHs) can act as a matrix. Layered double hydroxides with intercalated glyphosate anions (MgAl-Gly-LDH) were synthesized by different methods: coprecipitation at constant pH (MgAl-Gly-LDH-c), synthesis under hydrothermal conditions (MgAl-Gly-LDH-ht), microwave method (MgAl-Gly-LDH-mw) and rehydration method (MgAl-Gly-LDH-re). All the synthesized samples were analyzed by X-ray phase analysis (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. It is shown that the methods of co-precipitation and synthesis under hydrothermal conditions are most suitable for the synthesis of hybrid materials. Samples of MgAl-Gly-LDH-ht and MgAl-Gly-LDH-c have a well-crystallized structure, unlike the sample of MgAl-Gly-LDH-re, in which the LDH phase is practically absent.

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Diouane, Youssra, Victor Oestreicher, Alvaro Seijas Da Silva, and Gonzalo Abellán. "Tuning the Structure of Layered Hydroxides for Boosting Energy Application Performance." ECS Meeting Abstracts MA2023-01, no. 13 (August 28, 2023): 1328. http://dx.doi.org/10.1149/ma2023-01131328mtgabs.

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We are currently on a race against the clock to protect our planet from greenhouse gas emissions. The solution could be inspired from mother nature talking about renewable energies or so-called green energies including wind, solar, hydraulic, biomass and so on, which allows us to reduce the fossil fuels consumption. However, these kinds of energy devices should be coupled to an energy storage system such as batteries and supercapacitors to compensate the absence of wind and sun. For this purpose, we are looking forward to developing strong energy and power application systems by focusing on the development of novel electrode materials. Among 2D materials, layered hydroxides emerge as one of the most attractive electrode materials based on earth-abundant metals, at the same time inside of this family, three type can distinguish: the first one is the Brucite-like structure1 (β-structure) where the metal is arranged in the octahedral position and the interlayer space is defined by Van-Der-Waals interaction. The second one is the Hydrotalcite-like structure also called Layered Double Hydroxide (LDH) recognized by the following formula MII 1-x MIII x (OH)2 Ax. xH2O. The LDH regroups in the same layer a divalent and trivalent metals and are both arranged in the octahedral position2. The Simonkolleite-like structure3 (α-structure) with M1-x Oh Mx Td (OH)2-x Ax. yH2O as formula, is the third type which only contains divalent metals arranged in tetrahedral (Td) and octahedral (Oh) position. Layer double hydroxides are explored materials in the energy field. Multiple studies have been reported on the behaviour of the layered hydroxides materials in energy storage4 and conversion5. This material is very appealing for researchers worldwide due to their good electrochemical behaviour, chemical versatility, electrochemical stability, and their low cost as well6. For instance, LDHs based on earth-abundant elements are good candidates for electrode materials for oxygen evolution reaction (OER) in alkaline condition, as well as for supercapacitors. However, one of the major drawback of these materials is their low electrical conductivity, which represents a limitation in the optimization of the electrochemical performance and the assemble of devices. Among the different approximation to overcome this issue, we are intensively working on the modulation of the electronic properties of LHs. In this line, Co-based α-layered hydroxides, exhibiting simonkolleite-like structure, can be an interesting case of study since the covalent bond between the hydroxylated layer and the anion (figure 1). Indeed, we have recently demonstrated that the electrical properties can be modulated by halide substitution6, where the band gap can be reduced by ligand to metal charge transfer as demonstrated by DFT+U simulations. Considering these previous results, we decided to analyse the role of these chemical modifications in terms of the electrochemical properties. Interestingly, our results evidence a better electrochemical activity of Co-based α-LHs in comparison with the typical β-LHs or LDHs analogues, in both OER and specific capacitance performance7. Moreover, in the case of α-LHs the values can be further enhanced by tuning the nature of the anion: for instance, structures containing iodide overpass in more than 40% those ones containing chloride, as mentioned by DFT+U simulation (figure 2). Hence, this work positions α-CoII hydroxides as key phases among the layered hydroxides family as electrode materials for energy storage and conversion, where the conductivity can be improved by anion substitution8. 1 Brindley, G. W.; Kao, C.-C. Structural and IR Relations among Brucite-like Divalent Metal Hydroxides. Phys. Chem. Miner. 1984, 10 (4), 187–191. 2 Du, Y.; O’Hare, D. Synthesis, Morphology, Structure, and Magnetic Characterization of Layered Cobalt Hydroxyisocyanates. Inorg. Chem. 2008, 47 (8), 3234–3242. 3 Oestreicher, V.; Dolle, C.; Hunt, D.; Fickert, M.; Abellán, G. Room Temperature Synthesis of Two-Dimensional Multilayer Magnets Based on α-CoII Layered Hydroxides. Nano Mater. Sci. 2022, 4 (1), 36–43. 4 Zhang, D.; Cao, J.; Zhang, X.; Zeng, Z.; Insin, N.; Qin, J.; Huang, Y. Modification Strategies of Layered Double Hydroxides for Superior Supercapacitors. Adv. Energy Sustain. Res. 2022, 3 (3), 2100183. 5 Wang, Y.; Yan, D.; El Hankari, S.; Zou, Y.; Wang, S. Recent Progress on Layered Double Hydroxides and Their Derivatives for Electrocatalytic Water Splitting. Adv. Sci. 2018, 5 (8), 1800064. 6 Oestreicher, V.; Hunt, D.; Torres-Cavanillas, R.; Abellán, G.; Scherlis, D. A.; Jobbágy, M. Halide-Mediated Modification of Magnetism and Electronic Structure of α-Co(II) Hydroxides: Synthesis, Characterization, and DFT+U Simulations. Inorg. Chem. 2019, 58 (14), 9414–9424. 7 R. Sanchis-Gual, V. Oestreicher, G. Abellan et al. Submitted. 8 Y. Diouane, V.Oestreicher, G. Abellan et al, manuscript in preparation Figure 1

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Nguyen, Tien A., V. Pham, Thanh L. Pham, Linh T. Tr Nguyen, I. Ya Mittova, V. O. Mittova, Lan N. Vo, Bich Tram T. Nguyen, Vuong X. Bui, and E. L. Viryutina. "Simple Synthesis of NdFeO3 Nanoparticles By the Co-Precipitation Method Based on a Study of Thermal Behaviors of Fe (III) and Nd (III) Hydroxides." Crystals 10, no. 3 (March 20, 2020): 219. http://dx.doi.org/10.3390/cryst10030219.

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In this study, a nanostructured NdFeO3 material was synthesized via a simple process of the hydrolysis of Nd (III) and Fe (III) cations in hot water with 5% NaOH as a precipitating agent. According to the results of the thermal behaviors of each hydroxide, either containing Fe (III) or Nd (III), the perovskite type of neodymium orthoferrite NdFeO3 was simply synthesized by annealing a mixture of Fe (III) and Nd (III) hydroxides at 750 °C. The nanostructured NdFeO3 was obtained in spherical granules with diameters of around 30 nm. The magnetic properties of the material were a coercive force (Hc) of 136.76 Oe, a remanent magnetization (Mr) of 0.68 emu·g–1, and a saturation magnetization (Ms) of 0.79 emu·g–1.

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Yudha, Cornelius Satria, Soraya Ulfa Muzayanha, Hendri Widiyandari, Ferry Iskandar, Wahyudi Sutopo, and Agus Purwanto. "Synthesis of LiNi0.85Co0.14Al0.01O2 Cathode Material and its Performance in an NCA/Graphite Full-Battery." Energies 12, no. 10 (May 17, 2019): 1886. http://dx.doi.org/10.3390/en12101886.

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Nickel-rich cathode material, NCA (85:14:1), is successfully synthesized using two different, simple and economical batch methods, i.e., hydroxide co-precipitation (NCA-CP) and the hydroxides solid state reaction method (NCA-SS), followed by heat treatments. Based on the FTIR spectra, all precursor samples exhibit two functional groups of hydroxide and carbonate. The XRD patterns of NCA-CP and NCA-SS show a hexagonal layered structure (space group: R_3m), with no impurities detected. Based on the SEM images, the micro-sized particles exhibit a sphere-like shape with aggregates. The electrochemical performances of the samples were tested in a 18650-type full-cell battery using artificial graphite as the counter anode at the voltage range of 2.7–4.25 V. All samples have similar characteristics and electrochemical performances that are comparable to the commercial NCA battery, despite going through different synthesis routes. In conclusion, the overall results are considered good and have the potential to be adapted for commercialization.

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Yamagata, Chieko, and Jose O. A. Paschoal. "Systematic Precipitation of Magnesium Hydroxide Using NH₄OH to Preparing MgO-PSZ Precursor Powder." Materials Science Forum 805 (September 2014): 712–17. http://dx.doi.org/10.4028/www.scientific.net/msf.805.712.

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The wide range of applications of zirconia based ceramics is due to stabilization of its tetragonal and cubic structures at room temperature, by controlled adding of dopants such as yttria, magnesia, calcia, ceria and some rare earth oxides. The advantage of the use of magnesia as dopant is not only due to its low cost, but fact that by controlling its ceramic processing, it is possible to control a specific microstructure for the specific application. The precipitation of magnesium hydroxides, using NH4OH as a precipitant, presents some difficulties due to the formation of a variety of soluble complexes of ammonia with magnesium, which inhibits the total precipitation of magnesium. In the present work, the influence of precipitant and metals concentrations and pH on the magnesium hydroxide precipitation was investigated. Magnesium chloride, zirconium oxychloride and NH4OH were used as starting materials. The precipitation of magnesium hydroxide depends on concentrations of OH-, Cl- and Mg2+. To achieve specific precipitation yield, lower the concentration of Mg2+ high molar ratio of [OH-]/[Cl-] is required. The pH measure is not enough to control Mg (OH)2 precipitation. The use of molar ratio of [OH-]/[Cl-] = 4.4, resulted in 95 % of Mg (OH)2 precipitation. The co-precipitation of Zr and Mg hydroxides, using the optimized molar ratio of [OH-]/[Cl-], the precipitation of Mg (OH)2 achieved in range of 97.6 to 98.3 %.

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Szabados, Márton, Adél Anna Ádám, Zsolt Kása, Kornélia Baán, Róbert Mucsi, András Sápi, Zoltán Kónya, Ákos Kukovecz, and Pál Sipos. "M(II)Al4 Type Layered Double Hydroxides—Preparation Using Mechanochemical Route, Structural Characterization and Catalytic Application." Materials 14, no. 17 (August 27, 2021): 4880. http://dx.doi.org/10.3390/ma14174880.

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The synthesis of the copper-poor and aluminum-rich layered double hydroxides (LDHs) of the CuAl4 type was optimized in detail in this work, by applying an intense mechanochemical treatment to activate the gibbsite starting reagent. The phase-pure forms of these LDHs were prepared for the first time; using copper nitrate and perchlorate salts during the syntheses turned out to be the key to avoiding the formation of copper hydroxide sideproducts. Based on the use of the optimized syntheses parameters, the preparation of layered triple and multiple hydroxides was also attempted using Ni(II), Co(II), Zn(II) and even Mg(II) ions. These studies let us identify the relative positions of the incorporating cations in the well-known selectivity series as Ni2+ >> Cu2+ >> Zn2+ > Co2+ >> Mg2+. The solids formed were characterized by using powder X-ray diffractometry, UV–Vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. The catalytic potential of the samples was investigated in carbon monoxide oxidation reactions at atmospheric pressure, supported by an in situ diffuse reflectance infrared spectroscopy probe. All solids proved to be active and the combination of the nickel and cobalt incorporation (which resulted in a NiCoAl8 layered triple hydroxide) brought outstanding benefits regarding low-temperature oxidation and increased carbon monoxide conversion values.

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Zeng, Zhenhua, Fabio Dionigi, Jing Zhu, Junwu Liang, Wei-Xue Li, Peter Strasser, and Jeffrey Greeley. "Fundamental Insights into Reaction Centers and Catalytic Mechanisms of Ni- and Co-Based Layered Oxyhydroxides for the Oxygen Evolution Reaction." ECS Meeting Abstracts MA2023-01, no. 36 (August 28, 2023): 1965. http://dx.doi.org/10.1149/ma2023-01361965mtgabs.

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Water splitting to generate green H2 fuel and O2 is essential for global CO2 reductions toward net-zero emissions. In this process, however, O2 generation at the anode through the oxygen evolution reaction (OER) is inherently slower by orders of magnitude than H2 generation at the cathode. Thus, improving OER efficiency has been a major effort in electrolysis. Ni-based and Co-based layered hydroxides are among the most active and studied non-previous catalysts in alkaline electrolytes. Although tremendous advances have been made toward improving the activity and the stability of the catalysts over the past decade, there is still a lack of fundamental insights into active sites and reaction mechanisms, which has hindered the establishment of structure-property relationships. This talk will first provide fundamental insights into reaction centers and catalytic mechanisms of classic Ni oxyhydroxides and Co oxyhydroxides with and without ligand intercalation. We will further discuss the multiple-site synergy in Ni- and Co-based layered double hydroxides (LDH) and ternary hydroxides. We will show that the OER proceeds via a Mars van Krevelen mechanism, starting with the oxidation of bridge OH at the reaction centers with dual metal sites, i.e., M1-OH-M2. We will demonstrate that, to approach the minimum overpotential dictated by a specific OH-OOH scaling relationship, the key is to break the OH-O scaling relationship. A possible route is to form binary metal oxyhydroxides with dual metal sites at the reaction centers or introduce a third element into NiFe LDH or CoFe LDH. If time permits, We will further discuss the role of the non-covalent interaction and polaron-like electronic states in promoting OER at M1-OH-M2 centers.

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Zhong, Haihong, Carlos Campos-Roldán, Yuan Zhao, Shuwei Zhang, Yongjun Feng, and Nicolas Alonso-Vante. "Recent Advances of Cobalt-Based Electrocatalysts for Oxygen Electrode Reactions and Hydrogen Evolution Reaction." Catalysts 8, no. 11 (November 19, 2018): 559. http://dx.doi.org/10.3390/catal8110559.

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This review summarizes recent progress in the development of cobalt-based catalytic centers as the most potentially useful alternatives to noble metal-based electrocatalysts (Pt-, Ir-, and Ru-based) towards the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in acid and alkaline media. A series of cobalt-based high-performance electrocatalysts have been designed and synthesized including cobalt oxides/chalcogenides, Co–Nx/C, Co-layered double hydroxides (LDH), and Co–metal-organic frameworks (MOFs). The strategies of controllable synthesis, the structural properties, ligand effect, defects, oxygen vacancies, and support materials are thoroughly discussed as a function of the electrocatalytic performance of cobalt-based electrocatalysts. Finally, prospects for the design of novel, efficient cobalt-based materials, for large-scale application and opportunities, are encouraged.

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WANG, De-yi, A. LEUTERITZ, U. WAGENKNECHT, and G. HEINRICH. "Self-assembling organomodified Co/Al based layered double hydroxides (LDH) via one-step route." Transactions of Nonferrous Metals Society of China 19, no. 6 (December 2009): 1479–82. http://dx.doi.org/10.1016/s1003-6326(09)60055-8.

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Yang, Yusen, Deming Rao, Yudi Chen, Siyuan Dong, Bin Wang, Xin Zhang, and Min Wei. "Selective Hydrogenation of Cinnamaldehyde over Co-Based Intermetallic Compounds Derived from Layered Double Hydroxides." ACS Catalysis 8, no. 12 (November 7, 2018): 11749–60. http://dx.doi.org/10.1021/acscatal.8b02755.

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Liu, Wu-Jun, Xiao Hu, Hong-Chao Li, and Han-Qing Yu. "Pseudocapacitive Ni-Co-Fe Hydroxides/N-Doped Carbon Nanoplates-Based Electrocatalyst for Efficient Oxygen Evolution." Small 14, no. 34 (July 31, 2018): 1801878. http://dx.doi.org/10.1002/smll.201801878.

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Richardson, Ian. "Crystal chemistry of layered single and double hydroxides." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C231. http://dx.doi.org/10.1107/s205327331409768x.

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Layered double hydroxides (LDH) are derived from layered single hydroxides by the substitution of a fraction (x) of the divalent metal cations by trivalent cations, with the charge balanced by anions in the space between the main hydroxide layers. LDH phases can have a range of metal cations and interlayer anions and the value of x can vary quite widely. Straightforward crystal-chemical and geometrical reasoning has resulted in new yet fundamental information about these phases [1, 2]. In particular: (1) It is now possible to calculate x from the `a' parameter of the unit cell or vice versa (whichever is known with the most confidence) for LDH phases that are based on Mg, Ni, Zn or Co; (2) The phase at x = 0 is shown to be an alpha form of M(OH)2 rather than the beta polymorph; (3) The extent to which the metal-oxygen octahedra in the main layer of LDH phases are squashed is now known to be independent of the type of the interlayer anions or the type of trivalent ion, which also has no substantial effect on the reduction in layer spacing that occurs as x increases; (4) It is now easy to create reliable structural models for hydrotalcite- and takovite-type LDH phases that have any trivalent ion (or ions) and any value of x; (5) The ordered distributions of trivalent cations that are possible in LDH phases have been clarified and a plausible explanation provided for the observed variation in the lower solid-solution limit [3]; (6) A reliable model for the crystal structure of beta-Zn(OH)2.

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Mohammadi, Saeedeh, Ayoub Esmailpour, Esmail Doustkhah, and Mohammad Hussein Naseef Assadi. "Stability Trends in Mono-Metallic 3d Layered Double Hydroxides." Nanomaterials 12, no. 8 (April 13, 2022): 1339. http://dx.doi.org/10.3390/nano12081339.

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Layered double hydroxides (LDHs) constitute a unique group of 2D materials that can deliver exceptional catalytic, optical, and electronic performance. However, they usually suffer from low stability compared to their oxide counterparts. Using density functional calculations, we quantitatively demonstrate the crucial impact of the intercalants (i.e., water, lactate, and carbonate) on the stability of a series of common LDHs based on Mn, Fe, and Co. We found that intercalation with the singly charged lactate results in higher stability in all these LDH compounds, compared to neutral water and doubly charged carbonate. Furthermore, we show that the dispersion effect aids the stability of these LDH compounds. This investigation reveals that certain intercalants enhance LDH stability and alter the bandgap favourably.

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Stepanova, Liudmila N., Roman M. Mironenko, Elena O. Kobzar, Natalia N. Leont’eva, Tatiana I. Gulyaeva, Anastasia V. Vasilevich, Aleksandra N. Serkova, Aleksei N. Salanov, and Aleksandr V. Lavrenov. "Synthesis of CuAl-, CoAl-, and CuCoAl-Catalysts from Layered Hydroxides for Furfural Hydrogenation." Eng 3, no. 4 (September 28, 2022): 400–411. http://dx.doi.org/10.3390/eng3040029.

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Catalysts based on CuAl-, CoAl-, and CuCoAl-layered hydroxides with M2+/Al = 2 and Cu/Co = 1 molar ratio were obtained. The effect of amount of cobalt on the structural properties, morphology, surface cations distribution, oxide phase formation, thermal stability of the samples and reduction of metals from them was studied. The effect of reaction conditions (temperature, time, pressure, solvent) and conditions of preliminary treatment of catalysts on their catalytic properties in furfural hydrogenation was established. High selectivity to furfuryl alcohol was observed for all the samples irrespective of pretreatment and reaction conditions. The synergetic effect in furfural hydrogenation between Co and Cu in the CuCoAlOx catalysts was revealed when ethanol is used as a solvent.

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Musella, Elisa, Isacco Gualandi, Erika Scavetta, Arianna Rivalta, Elisabetta Venuti, Meganne Christian, Vittorio Morandi, Angelo Mullaliu, Marco Giorgetti, and Domenica Tonelli. "Newly developed electrochemical synthesis of Co-based layered double hydroxides: toward noble metal-free electro-catalysis." Journal of Materials Chemistry A 7, no. 18 (2019): 11241–49. http://dx.doi.org/10.1039/c8ta11812d.

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Ramesh, Thimmasandra Narayan, and Theeta Lakshamaiah Madhu. "Thermal Decomposition Studies of Layered Metal Hydroxynitrates (Metal: Cu, Zn, Cu/Co, and Zn/Co)." International Journal of Inorganic Chemistry 2015 (January 27, 2015): 1–11. http://dx.doi.org/10.1155/2015/536470.

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Layered metal hydroxynitrates and mixed metal hydroxynitrates (copper/cobalt hydroxynitrates and zinc/cobalt hydroxynitrates at different mole ratios) were synthesized by hydrolysis of urea and metal nitrates at 140°C. Layered metal hydroxyl nitrates derive their structure from brucite mineral and generally crystallize in hexagonal and monoclinic phases. Isothermal decomposition studies of Cu2(OH)3(NO3), Co2(OH)3(NO3), Cu1.5Co0.5(OH)3(NO3), Cu1.34Co0.66(OH)3(NO3), Zn5(OH)8(NO3)2(H2O)2, Zn3.75Co1.25(OH)8(NO3)2(H2O)2, and Zn3.35Co1.65(OH)8(NO3)2(H2O)2 samples were carried out at different intervals of temperature and the structural transformations during the process were monitored using powder X-ray diffractograms. Biphasic mixture of metal hydroxynitrate/metal oxide is observed in case of cobalt/zinc based layered hydroxynitrates, while copper hydroxynitrate or copper/cobalt metal hydroxynitrate decomposes in a single step. The decomposition temperatures of layered metal hydroxynitrates and mixed layered metal hydroxides depend on the method of preparation, their composition and the nature of metal ion, and their coordination.

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Jovanov, V., O. Rudic, J. Ranogajec, and E. Fidanchevska. "Synthesis of nanocomposite coating based on TiO₂/ZnAl layer double hydroxides." Materiales de Construcción 67, no. 325 (February 1, 2017): 112. http://dx.doi.org/10.3989/mc.2017.07215.

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The aim of this investigation was the synthesis of nanocomposite coatings based on Zn-Al layered double hydroxides (Zn-Al LDH) and TiO2. The Zn-Al LDH material, which acted as the catalyst support of the active TiO2 component (in the content of 3 and 10 wt. %), was synthesized by a low super saturation co-precipitation method. The interaction between the Zn-Al LDH and the active TiO2 component was accomplished by using vacuum evaporation prior to the mechanical activation and only by mechanical activation. The final suspension based on Zn-Al LDH and 10wt. % TiO2, impregnated only by mechanical activation, showed the optimal characteristics from the aspect of particle size distribution and XRD analysis. These properties had a positive effect on the functional properties of the coatings (photocatalytic activity and self-cleaning efficiency) after the water rinsing procedure.

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do Carmo, Weberton, Gustavo de Carvalho, Juliana da Silva, Luciano Chagas, Alexandre Leitão, and Renata Diniz. "Investigation of layered double hydroxides type ZnMgAl-carbonate and derivates." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1100. http://dx.doi.org/10.1107/s2053273314088998.

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Layered double hydroxides (LDHs) or hydrotalite-like compounds belong to a class of synthetic two-dimensional inorganic materials with lamellar structures, where the hydroxyl-hydrated compounds are formed by chemical substitution of divalent ion of the brucite-like octahedral layers by trivalent ions [1]. The LDH are represented by the general formula, Figure a , where M2+, M3+ are divalent and trivalent cation and Am- is interlayer anion responsible by charge balancing, the range of divalent and trivalent ions (x) varies normally between 0.17 a 0.33. According Montanari and co-works [2] compounds type ZnAl-hydrotalcites (ZnAl-HT) have relevant industrial interest; however the scientific literature concerning this material as catalysts or catalyst precursor is scarce. Based on this fact, in the present communication we will present a studied on how the variation in percentage of Zinc in a ZnMgAl-HT catalyst precursor can influence the formation of mixed oxides after calcination. The ZnMgAl-HTs, Figure b , y=5, 10,15,20,25,50,75 and 100% were prepared by co-precipitation and urea method. Mg-Zn/Al mixed oxides were prepared from calcinations of hydrotalcites precursors at 5000C for 4 hours. The material synthesized were characterized by X-ray powder diffraction, the measurements were carried out in Bruker D8 DaVinci diffractometer, equipped with CuKα radiation , LynxEye linear Position Sensitive Detector, Ni-filter. Data was collect between 8 and 800in 2θ with step size of 0.020and the count time of 0.05 per step. Soller slit 2.50of divergence and 0.2 mm primary slit were used. For the ZnMgAl-HT samples the measurements were performed at different temperatures, range 25-12000C, heating rate 50C/min. It was observed differences among XRD patterns for y greater than 25% of Zn in urea method at 5000C, and for co-precipitation method just for the substitution at 50 and 75% of Zn. These results suggested that the increase in Zn percentage change the structure of calcinated samples.

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Qiu, Haifa, Tengfei Du, Junfeng Wu, Yonglong Wang, Jian Liu, Shihai Ye, and Sheng Liu. "Towards deriving Ni-rich cathode and oxide-based anode materials from hydroxides by sharing a facile co-precipitation method." Dalton Transactions 47, no. 20 (2018): 6934–41. http://dx.doi.org/10.1039/c8dt00893k.

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Zeng, Zhenhua, Jing Zhu, Fabio Dionigi, Wei-Xue Li, Peter Strasser, and Jeffrey Greeley. "Catalytically-Active Phases and Reaction Mechanism of Ni-Based and Co-Based Layered Double Hydroxides for the Oxygen Evolution Reaction." ECS Meeting Abstracts MA2022-01, no. 34 (July 7, 2022): 1368. http://dx.doi.org/10.1149/ma2022-01341368mtgabs.

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Electrochemical water splitting using renewable energy is a key route to generate green H2 fuel. In this process, however, O2 generation at the anode through the oxygen evolution reaction (OER) is inherently slower by over four orders of magnitude than H2 generation at the cathode. Thus, improving OER efficiency has been a majority effort in electrolysis. Ni-based and Co-based layered double hydroxides (LDHs) are among the most active and studied catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. Because it happens under extremely oxidative aqueous conditions, however, in-situ crystal structures of the OER active phase are still largely unknown, significantly hindering the establishment of structure-property relationships. In this talk, we provide the first direct atomic-scale evidence that, under applied anodic potentials, NiFe and CoFe LDHs oxidize from as-prepared α-phases to activated γ-phases. The OER-active γ-phases are characterized by about 8% contraction of the lattice spacing and switching of the intercalated ions from carbonate to potassium. The calculated surface phase diagrams indicate that surface O sites are saturated with H by forming bridge OH, and coordinatively unsaturated metal sites are poisoned by OH adsorption under OER conditions. These structures, and the associated reaction free energies, suggest that the OER proceeds via a Mars van Krevelen mechanism, starting with the oxidation of bridge OH at the reaction centers with dual metal sites, i.e., M1-OH-M2. Our study suggests that the compound-dependent activity originates from the dual-metal site feature of the reaction centers. While this feature does not influence the OH-OOH scaling relationship, it leads to diverse OH-O scaling relationships, including those with near-zero slopes and negative slopes. Breaking OH-OOH scaling relationships were frequently discussed in the literature, as it determines the minimum overpotential. However, our study showed that, to approach the minimum overpotential dictated by a specific OH-OOH scaling relationship, the key is to break the OH-O scaling relationship. A possible route is to form binary metal oxyhydroxides with dual metal sites at the reaction centers or introduce a third element into NiFe LDH or CoFe LDH. References: Dionigi, Z. Zeng, I. Sinev, T. Merzdorf, S. Deshpande, M. B. Lopez, S. Kunze, I. Zegkinoglou, H. Sarodnik, D. Fan, A. Bergmann, J. Drnec, J. F. d. Araujo, M. Gliech, D. Teschner, J. Zhu, W.-X. Li, J. Greeley, B. R. Cuenya, P. Strasser, Nature Communications 2020, 11, 2522. Dionigi, J. Zhu, Z. Zeng, T. Merzdorf, H. Sarodnik, M. Gliech, L. Pan, W.-X. Li, J. Greeley, P. Strasser, Angew. Chem., Int. Ed. 2021, 60, 14446-14457.

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Kim, Sanghoon, Pierrick Durand, Erwan André, and Cédric Carteret. "Enhanced photocatalytic ability of Cu, Co doped ZnAl based mixed metal oxides derived from layered double hydroxides." Colloids and Surfaces A: Physicochemical and Engineering Aspects 524 (July 2017): 43–52. http://dx.doi.org/10.1016/j.colsurfa.2017.04.019.

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Zhao, Shen, Kezhi Li, Su Jiang, and Junhua Li. "Pd–Co based spinel oxides derived from pd nanoparticles immobilized on layered double hydroxides for toluene combustion." Applied Catalysis B: Environmental 181 (February 2016): 236–48. http://dx.doi.org/10.1016/j.apcatb.2015.08.001.

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Tian, Yahong, Lingzhi Zhu, Enshan Han, Mei Shang, and Mengchao Song. "Effect of templating agent on Ni, Co, Al-based layered double hydroxides for high-performance asymmetric supercapacitors." Ionics 26, no. 1 (August 23, 2019): 367–81. http://dx.doi.org/10.1007/s11581-019-03201-3.

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Kim, Sanghoon, Jean Fahel, Pierrick Durand, Erwan André, and Cédric Carteret. "Ternary Layered Double Hydroxides (LDHs) Based on Co-, Cu-Substituted ZnAl for the Design of Efficient Photocatalysts." European Journal of Inorganic Chemistry 2017, no. 3 (January 18, 2017): 669–78. http://dx.doi.org/10.1002/ejic.201601213.

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Zaffora, Andrea, Bartolomeo Megna, Barbara Seminara, Francesco Di Franco, and Monica Santamaria. "Ni,Fe,Co-LDH Coated Porous Transport Layers for Zero-Gap Alkaline Water Electrolyzers." Nanomaterials 14, no. 5 (February 23, 2024): 407. http://dx.doi.org/10.3390/nano14050407.

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Next-generation alkaline water electrolyzers will be based on zero-gap configuration to further reduce costs related to technology and to improve performance. Here, anodic porous transport layers (PTLs) for zero-gap alkaline electrolysis are prepared through a facile one-step electrodeposition of Ni,Fe,Co-based layered double hydroxides (LDH) on 304 stainless steel (SS) meshes. Electrodeposited LDH structures are characterized using Scanning Electron Microscopy (SEM) confirming the formation of high surface area catalytic layers. Finally, bi and trimetallic LDH-based PTLs are tested as electrodes for oxygen evolution reaction (OER) in 1 M KOH solution. The best electrodes are based on FeCo LDH, reaching 10 mA cm−2 with an overpotential value of 300 mV. These PTLs are also tested with a chronopotentiometric measurement carried out for 100 h at 50 mA cm−2, showing outstanding durability without signs of electrocatalytic activity degradation.

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Xiao, Kaiming, Lei Zhou, Mingfei Shao, and Min Wei. "Fabrication of (Ni,Co)0.85Se nanosheet arrays derived from layered double hydroxides toward largely enhanced overall water splitting." Journal of Materials Chemistry A 6, no. 17 (2018): 7585–91. http://dx.doi.org/10.1039/c8ta01067f.

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Bukhtiyarova, Marina V., Olga A. Bulavchenko, Andrey V. Bukhtiyarov, Alexey L. Nuzhdin, and Galina A. Bukhtiyarova. "Selective Hydrogenation of 5-Acetoxymethylfurfural over Cu-Based Catalysts in a Flow Reactor: Effect of Cu-Al Layered Double Hydroxides Synthesis Conditions on Catalytic Properties." Catalysts 12, no. 8 (August 10, 2022): 878. http://dx.doi.org/10.3390/catal12080878.

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Cu-containing layered double hydroxides (LDHs) were synthesized by a co-precipitation method at different reaction conditions, such as aging time, pH, precipitation rate and synthesis temperature. The effect of these parameters on the structure and chemical composition of the catalysts were investigated using a set of physical methods, including thermogravimetric analysis (TGA), X-ray diffraction (XRD), H2-TPR and in situ X-ray photoelectron spectroscopy (XPS). It allowed for checking of the reducibility of the samples. 5-Acetoxymethylfurfural was catalytically hydrogenated to 5-(acetoxymethyl)-2-furanmethanol (AMFM) over Cu-containing catalysts synthesized from layered double hydroxides so as to investigate its catalytic properties in flow reaction. It was shown that synthesis pH decreasing from 10 to 8 resulted in rise of AMF conversion that coincided with the higher surface Cu/Al ratio obtained by XPS. Preferable aging time of LDH materials for obtaining the most active catalyst was 2 h, an amount of time that favored the production of the catalyst with high surface Cu/Al ratio up to 0.38. Under optimized reaction conditions, the AMFM yield was 98%. Finally, a synthesis strategy for the preparation of highly efficient Cu-based hydrogenation catalyst with optimized characteristics is suggested.

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Chen, Liyong, Huifang Wang, Xiaoshuang Shen, Yingyue Zhang, Dezhi Li, and Chunying Duan. "A novel route for the generation of Co/CoZn/CoNi layered double hydroxides at ambient temperature." Inorganic Chemistry Frontiers 6, no. 6 (2019): 1415–21. http://dx.doi.org/10.1039/c9qi00340a.

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Huang, Biao, Wensong Wang, Tao Pu, Jie Li, Jikui Zhu, Chenglan Zhao, Li Xie, and Lingyun Chen. "Two-dimensional porous (Co, Ni)-based monometallic hydroxides and bimetallic layered double hydroxides thin sheets with honeycomb-like nanostructure as positive electrode for high-performance hybrid supercapacitors." Journal of Colloid and Interface Science 532 (December 2018): 630–40. http://dx.doi.org/10.1016/j.jcis.2018.08.019.

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Marwa F. Abed and Ayad A.H. Faisal. "NA-ALGINATE BEADS OF CALCIUM / IRON-LAYERED DOUBLE HYDROXIDE FOR TREATING WATER CONTAMINATED WITH AMOXICILLIN ANTIBIOTIC." IRAQI JOURNAL OF AGRICULTURAL SCIENCES 55, no. 2 (April 28, 2024): 858–67. http://dx.doi.org/10.36103/x9f67y59.

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The objective of this study was to prepare an adsorbent material from eggshells of chicken banished to the ambient as wastes to satisfy the ecological requirements of sustainable. The preparation process based on the extraction of calcium ions from eggshells and these ions must be reacted with iron to form nanoparticles of (Ca/Fe)-layered double hydroxides (LDHs) which immobilized as Na-alginate beads. Molar ration of calcium to iron, pH and dosage of LDH nanoparticles must be equal to 1, 12 and 5 g/100 mL to ensure that the prepared beads have highest ability to remove of Amoxicillin (AMOX) antibiotic with removal efficiency equal to 32% for operational conditions of Co=100 mg/L, beads dosage=0.5 g/50 mL, speed=200 rpm, pH=7 for 3 hrs. To increase this efficiency to ≥ 90%, best conditions must be time 90 min, pH 7, and beads mass 1.2 g/ 50 mL for Co 100 mg/L at 200 rpm in the batch mode. The Pseudo second order has high capability in the description of such tests with coefficient of determination (R2) ≥ 0.9924 and sum of squared error (SSE) ≤ 0.1287. Hence, the sorption of AMOX onto beads is governed by the chemisorption process. The reflections of XRD analysis proved the presence of (Ca/Fe)-LDH nanoparticles with size of 13.49 nm, calcium hydroxide (Ca(OH)2) and calcium carbonate (CaCO3)

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Saei, Worawee, Joachim Pasel, Fabian Scheepers, and Carsten Korte. "Developing Cu-Co-Based Catalysts for Enhanced OER in Alkaline Water Electrolysis." ECS Meeting Abstracts MA2023-02, no. 57 (December 22, 2023): 2775. http://dx.doi.org/10.1149/ma2023-02572775mtgabs.

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Copper, Cobalt-based (CuCo-based) catalysts are promising candidates for the anodes of alkaline water electrolyzers due to their high electrical conductivity, variable chemical state, and the potential for cost-effective large-scale production. However, the effective chemical composition and structure of these catalysts are still being explored. In this work, the focus is on the proposal CuCo-based catalysts for the oxygen evolution reaction (OER) in alkaline water electrolysis, with significant advantages for their use in anion exchange membrane (AEM) electrolyzer systems. CuCo-based catalysts with varying Cu:Co ratios were synthesized using a co-precipitation method and heat treatment, resulting in spinel type (oxides), CuCo-O, or brucite type structures (hydroxides), CuCo-OH. The catalysts were characterized using XRD, SEM, EDX, TEM and ICP-OES to confirm their morphology and composition. The OER catalytic performance of the catalysts was evaluated using rotating disk electrode (RDE) measurements with a 3-electrode system and 1 M KOH as the electrolyte. Our results show that CuCo-OH provides lower overpotentials than CuCo-O at a current density of 10 mA/cm2. Nevertheless, CuCo-O exhibits a more consistent performance than CuCo-OH, indicating its superior properties in terms of reproducibility and reliability. Additionally, we propose a promising Cu:Co mol ratio of CuCo-OH and CuCo-O. These findings highlight the importance of the chemical composition and provides insight into the structure design of OER catalysts for alkaline water electrolysis. The results suggest a synergistic effect of Cu and Co in the catalyst composition, which could be further explored in future research.

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Feng, Yanyan, Baohua Xiao, Kaiwen Bo, Hong Chen, and Wen Yang. "Controllable preparation of porous Ca-Mg-Al hydroxides based adsorbents and their CO₂ adsorption performances." Ferroelectrics 594, no. 1 (July 4, 2022): 44–56. http://dx.doi.org/10.1080/00150193.2022.2078115.

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Richardson, Ian G. "Zn- and Co-based layered double hydroxides: prediction of theaparameter from the fraction of trivalent cations andvice versa." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 69, no. 4 (July 18, 2013): 414–17. http://dx.doi.org/10.1107/s2052519213017545.

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Zhao, Jie, Yun Lu, Debin Wu, Yuancheng Qin, Yu Xie, Yue Guo, Waseem Raza, et al. "Regulating divalent metal species in aluminum-based layered double hydroxides to selectively promote photocatalytic CO production from CO2." Separation and Purification Technology 305 (January 2023): 122508. http://dx.doi.org/10.1016/j.seppur.2022.122508.

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Vasile, Eugeniu, Ionut-Cristian Radu, Bianca Galateanu, Maria Rapa, Ariana Hudita, Dana Jianu, Paul-Octavian Stanescu, Horia Cioflan, and Catalin Zaharia. "Novel Nanocomposites Based on Bacterial Polyester/LDH-SDS Clay for Stem Cells Delivery in Modern Wound Healing Management." Materials 13, no. 20 (October 10, 2020): 4488. http://dx.doi.org/10.3390/ma13204488.

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Nanocomposite materials based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) and modified mineral clay layered double hydroxides (LDH-SDS) were explored as novel nanostructured materials for potential tissue engineering applications. The mineral clay inorganic phase was modified with an anionic long-chain structure of carbon atoms, such as sodium dodecyl sulfate, in order to increase the compatibility between the two phases. The melt intercalation method used for nanocomposite fabrication ensures a good dispersion of the modified LDH-SDS within the polymer matrix without using a toxic solvent (chloroform). The nanocomposites were found to have an intercalated/exfoliated structure with an enhanced Young modulus and increased stiffness. This could allow them to be considered for autologous stem cells dressings in the view of efficient wound healing applications.

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Li, Chenguang, Yupeng Bao, Enzhou Liu, Binran Zhao, and Tao Sun. "Recent Advances of Modified Ni (Co, Fe)-Based LDH 2D Materials for Water Splitting." Molecules 28, no. 3 (February 3, 2023): 1475. http://dx.doi.org/10.3390/molecules28031475.

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Water splitting technology is an efficient approach to produce hydrogen (H2) as an energy carrier, which can address the problems of environmental deterioration and energy shortage well, as well as establishment of a clean and sustainable hydrogen economy powered by renewable energy sources due to the green reaction of H2 with O2. The efficiency of H2 production by water splitting technology is intimately related with the reactions on the electrode. Nowadays, the efficient electrocatalysts in water splitting reactions are the precious metal-based materials, i.e., Pt/C, RuO2, and IrO2. Ni (Co, Fe)-based layered double hydroxides (LDH) two-dimensional (2D) materials are the typical non-precious metal-based materials in water splitting with their advantages including low cost, excellent electrocatalytic performance, and simple preparation methods. They exhibit great potential for the substitution of precious metal-based materials. This review summarizes the recent progress of Ni (Co, Fe)-based LDH 2D materials for water splitting, and mainly focuses on discussing and analyzing the different strategies for modifying LDH materials towards high electrocatalytic performance. We also discuss recent achievements, including their electronic structure, electrocatalytic performance, catalytic center, preparation process, and catalytic mechanism. Furthermore, the characterization progress in revealing the electronic structure and catalytic mechanism of LDH is highlighted in this review. Finally, we put forward some future perspectives relating to design and explore advanced LDH catalysts in water splitting.

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Journal articles on the topic 'Co based hydroxides'

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