Relevant bibliographies by topics / Zirconia-based acid catalysts

Academic literature on the topic 'Zirconia-based acid catalysts'

Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

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Journal articles on the topic "Zirconia-based acid catalysts"

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Pothu, Ramyakrishna, Naresh Mameda, Harisekhar Mitta, Rajender Boddula, Raveendra Gundeboyina, Vijayanand Perugopu, Ahmed Bahgat Radwan, Aboubakr M. Abdullah, and Noora Al-Qahtani. "High Dispersion of Platinum Nanoparticles over Functionalized Zirconia for Effective Transformation of Levulinic Acid to Alkyl Levulinate Biofuel Additives in the Vapor Phase." Journal of Composites Science 6, no. 10 (October 10, 2022): 300. http://dx.doi.org/10.3390/jcs6100300.

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In recent years, functionalized metal oxides have been gaining popularity for biomass conversion to fuels and chemicals due to the global energy crisis. This study reports a novel catalyst based on noble metal immobilization on functionalized zirconia that has been successfully used in the production of biofuel alkyl levulinates (ALs) from lignocellulosic biomass-derived levulinic acid (LA) under vapor-phase. The wet impregnation method was used to immobilize Pt-metal nanoparticles on zirconia-based supports (silicotungstic acid zirconia, STA-ZrO2; sulfated zirconia, S-ZrO2; and tetragonal zirconia, t-ZrO2). A variety of physicochemical techniques were used to characterize the prepared catalysts, and these were tested under atmospheric pressure in continuous flow esterification of LA. The order of catalytic activity followed when ethyl levulinate was produced from levulinic acid via esterification: Pt/STA-ZrO2 ≫ Pt/S-ZrO2 ≫ Pt/t-ZrO2. Moreover, it was found that ALs synthesis from LA with different alcohols utilizing Pt/STA-ZrO2 catalyst followed the order ethyl levulinate ≫ methyl levulinate ≫ propyl levulinate≫ butyl levulinate. This work outlines an excellent approach to designing efficient catalysts for biofuels and value-added compounds made from biomass.
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Bakkali, Bouchra El, Guido Trautwein, Juan Alcañiz-Monge, and Santiago Reinoso. "Zirconia-supported 11-molybdovanadophosphoric acid catalysts: effect of the preparation method on their catalytic activity and selectivity." Acta Crystallographica Section C Structural Chemistry 74, no. 11 (October 18, 2018): 1334–47. http://dx.doi.org/10.1107/s2053229618013013.

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The oxidation of adamantane with hydrogen peroxide catalyzed by zirconia-supported 11-molybdovanadophosphoric acid is shown to be a suitable green route for the synthesis of adamantanol and adamantanone. This work evaluates how the catalyst activity and selectivity are affected by some of its preparative parameters, such as the method for supporting the catalytically active heteropoly acid over the zirconia matrix or the pretreatments applied to the resulting materials before being used as heterogeneous catalysts. Our results indicate that the most effective catalysts able to maintain their activity after several reaction runs are those prepared by following the sol-gel route, whereas the most selective catalysts are those obtained by impregnation methods. Moreover, the calcination temperature has also been identified as a relevant parameter influencing the performance of catalysts based on supported heteropoly acids. The increasing catalytic activity observed over several consecutive reaction runs has been attributed to the formation of peroxo derivatives of polyoxometalate clusters at the surface of the catalyst and their accumulation after each reaction cycle.
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Vasić, Katja, Gordana Hojnik Podrepšek, Željko Knez, and Maja Leitgeb. "Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides." Catalysts 10, no. 2 (February 17, 2020): 237. http://dx.doi.org/10.3390/catal10020237.

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The development of solid acid catalysts, especially based on metal oxides and different magnetic nanoparticles, gained much awareness recently as a result of the development of different nano-based materials. Solid acid catalysts based on metal oxides are promising for the (trans)esterification reactions of different oils and waste materials for biodiesel production. This review gives a brief overview of recent developments in various solid acid catalysts based on different metal oxides, such as zirconia, zinc, titanium, iron, tungsten, and magnetic materials, where the catalysts are optimized for various reaction parameters, such as the amount of catalyst, molar ratio of oil to alcohol, reaction time, and temperature. Furthermore, yields and conversions for biodiesel production are compared. Such metal-oxide-based solid acid catalysts provide more sustainable, green, and easy-separation synthesis routes with high catalytic activity and reusability than traditionally used catalysts.
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Reena, SS, SMZ Shamshuddin, VT Vasantha, and JQ D’Souza. "Synthesis of solketal over zirconia based acid catalysts." Bangladesh Journal of Scientific and Industrial Research 54, no. 1 (March 25, 2019): 31–38. http://dx.doi.org/10.3329/bjsir.v54i1.40728.

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Microwave assisted synthesis of ‘solketal’ over zirconia (ZrO2) and its modified forms (Mo(VI)/ZrO2, W(VI)/ZrO2 and V(V)/ZrO2) coated on honeycomb monoliths is reported. The solid acids were coated on honeycomb monoliths by ‘dip and dry’ method and characterized for their surface acidity, crystalinity, functionality, morphology and elemental analysis by using techniques such as NH3-Temperature programmed desorption (NH3-TPD), powder X-ray diffraction (PXRD), Fourier transform-infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Inductively coupled plasma-optical emission spectroscopy (ICP-OES). The honeycomb monoliths coated with solid acids were employed as catalysts in the condensation of glycerol with acetone to synthesize solketal under microwave irradiation conditions. The reaction conditions such as molar ratio of the reactants (glycerol: acetone), reaction temperature, reaction time were studied to obtain highest possible yield of solketal with greater selectivity. The catalytic activity of honeycomb catalytic material was compared with the powder forms of the catalysts. 98% yield of solketal with 98% selectivity was achieved over Mo(VI)/ZrO2 coated on a honeycomb monolith in a very shorter reaction time of 8 min at 60 oC under microwave heating. These honeycomb catalytic material were found to be easily reactivable and reusable atleast for 6 reaction cycles. Hence, honeycomb catalysts were found to be efficient, economical and effective in the synthesis of value added chemical such as solketal. A possible mechanism for the formation of solketal is proposed. Bangladesh J. Sci. Ind. Res.54(1), 31-38, 2019
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Zhang, Wenwen, Zichun Wang, Jun Huang, and Yijiao Jiang. "Zirconia-Based Solid Acid Catalysts for Biomass Conversion." Energy & Fuels 35, no. 11 (May 19, 2021): 9209–27. http://dx.doi.org/10.1021/acs.energyfuels.1c00709.

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Stojkovic, N., M. Vasic, M. Marinkovic, M. Randjelovic, M. Purenovic, P. Putanov, and A. Zarubica. "A comparative study of n-hexane isomerization over solid acids catalysts: Sulfated and phosphated zirconia." Chemical Industry and Chemical Engineering Quarterly 18, no. 2 (2012): 209–20. http://dx.doi.org/10.2298/ciceq110602062s.

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Two series of zirconia based catalysts promoted with either sulfates or phosphates were prepared, calcined at different temperatures (600 and 700?C) and evaluated for the n-hexane isomerization reaction. The catalysts with different concentrations of sulfates or phosphates (4 or 10 wt. %) were characterized by BET, XRD, SEM methods, and total acidity was evaluated by using the Hammett indicators. Their final catalytic performances were correlated with their physical-chemical properties (surface, structural, textural and morphological). It was found that sulfated zirconia catalyst calcined at lower temperature showed the highest initial activity of all tested catalysts as the result of favorable total acidity, mesopore texture and structural properties. Somewhat lower activity of the sulfated catalyst calcined at higher temperature is related to the content of acid groups partially removed during thermal treatment, thus, lower total acidity, and also to less favorable textural and structural features. Negligible activity of phosphated zirconia catalysts is connected with low total acidity despite the positive status of particular property showing the complexity of the active phase/site formation in the catalyst.
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Huang, Yin-yan, Bi-ying Zhao, and You-chang Xie. "Preparation of zirconia-based acid catalysts from zirconia aerogel of tetragonal phase." Applied Catalysis A: General 172, no. 2 (September 1998): 327–31. http://dx.doi.org/10.1016/s0926-860x(98)00138-0.

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Luo, Wen, Qiongyao Zeng, Akram Ali Nasser Mansoor Al-Haimi, Ming Li, Lingmei Yang, Zhigang Sun, Shiyou Xing, Junying Fu, and Pengmei Lv. "Preparation and Performance of the Lipid Hydrodeoxygenation of a Nickel-Induced Graphene/HZSM-5 Catalyst." Catalysts 12, no. 6 (June 7, 2022): 627. http://dx.doi.org/10.3390/catal12060627.

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Graphene-encapsulated nickel nanoclusters are a feasible strategy to inhibit the nickel deactivation of nickel-based catalysts. In this work, graphene-encapsulated catalysts (Ni@C/HZSM-5) were prepared by a compression forming process, using pseudo-boehmite, Al2O3, and ZrO2 as binders. The pseudo-boehmite was gradually transformed from amorphous to crystalline alumina at high temperatures, which destroyed the nucleation of Ni@C. In contrast, the crystal-stabilized zirconia was more favorable for the nucleation of Ni@C. The extensive dispersion of alumina on the surface of HZSM-5 covers the acid sites of HZSM-5. In contrast, when zirconia was used as the binder, the binder existed in the form of the direct aggregation of ~100 nm zirconia spheres; this distribution form reduced better the damage of the binder to the acid site of the catalyst. Furthermore, the particle size of Ni crystals in the graphene-encapsulated catalysts decreased significantly (mostly <11 nm), and no evident agglomeration of nickel particles appeared. It was found that the stabilization of the metal interface delayed, to an extent, the accumulation rate of carbon deposits and, thus, postponed the deactivation of the acid sites. After 8 h of continuous reaction, the conversion of the traditional catalyst Ni/Z5+Zr dropped significantly to 60%. In contrast, the conversion of Ni@C catalysts prepared with ZrO2 remained above 90%. The regeneration test shows that air roasting could effectively remove carbon deposits and restore the catalyst activity.
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Checa, Manuel, Vicente Montes, Jesús Hidalgo-Carrillo, Alberto Marinas, and Francisco Urbano. "Influence of Boron, Tungsten and Molybdenum Modifiers on Zirconia Based Pt Catalyst for Glycerol Valorization." Nanomaterials 9, no. 4 (April 2, 2019): 509. http://dx.doi.org/10.3390/nano9040509.

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The influence of boron, tungsten and molybdenum modifiers on zirconia-based Pt catalyst was studied for glycerol valorization. Zirconia modified supports were prepared by impregnation of ZrO2 with either boric, silicontungstic or phosphomolybdic acids to obtain supports with enhanced Brönsted acidic properties. The modified supports were subsequently impregnated with chloroplatinic acid to obtain Pt-based catalysts. Pt incorporation resulted in the increase in Lewis acidity of the solids, being more significant for the Pt//W/ZrO2 catalyst. Reduced Pt catalysts were tested for the liquid-phase glycerol hydrogenolysis, observing a synergistic effect between catalyst acid sites and metal function that proved to be crucial in glycerol hydrogenolysis. The Pt//W/ZrO2 catalyst was the most active catalyst in this reaction, being the only leading to 1,3-PDO (45% sel., 160 °C) while Pt//Mo/ZrO2 is the best option for 1,2-PDO (49% sel., 180 °C). Reusability studies carried out for Pt//W/ZrO2 showed that catalytic activity dropped after the first use, remaining constant for the second and subsequent ones. Selectivity to reaction products also changes during reuses. Therefore, the selectivity to 1,2 PDO increases in the first reuse in detriment to the selectivity to n-propanol whereas the selectivity to 1,3-PDO remains constant along the uses. This behavior could be associated to the lixiviation of W species and/or catalyst fouling during reaction runs.
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García-Pérez, Diana, Maria Consuelo Alvarez-Galvan, Jose M. Campos-Martin, and Jose L. G. Fierro. "Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization." Catalysts 11, no. 1 (January 11, 2021): 88. http://dx.doi.org/10.3390/catal11010088.

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Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.
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Dissertations / Theses on the topic "Zirconia-based acid catalysts"

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Zhang, Yue, and 张悦. "Synthesis and characterization of zirconia based solid acid catalysts for biodiesel production." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49858828.

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Biodiesel is a promising renewable alternative fuel to fossil energy. For the biodiesel production from low-cost feedstock, a pretreatment step is essential, which is the esterification of free fatty acids (e.g. oleic acid) in the feedstock in order to avoid soap formation and minimize catalyst deactivation. Sulfuric acid modified zirconia (H2SO4-ZrO2) is known as an effective heterogeneous catalyst for esterification. However, due to rapid 〖SO〗_4^(2-) leaching, its reusability is low and its practical use is thus largely hindered. Zirconia supported on silica (ZrO2-SiO2) serves as a kind of non-sulfated zirconia catalyst against the leaching of the active species. Moreover, the silica support offers a large surface area and excellent thermal stability, which can accommodate a number of active zirconia species. Furthermore, there are Zr-O-Si bondings at the contact area between ZrO2 and SiO2, which might result in the formation of a new strong acid species and induce an increase of the zirconia acidity accordingly. Herein, two types of ZrO2-SiO2 catalysts were prepared, by using the reverse microemulsion method and sol-gel-hydrothermal method, denoted as ZrO2-SiO2-ME and ZrO2-SiO2-SG, respectively. The as synthesized ZrO2-SiO2 were characterized by TEM, SEM, EDX, XRD, BET and IR. ZrO2-SiO2-ME demonstrated a good dispersion of ZrO2 nanoparticles, encapsulating in the monodispersed SiO2 host matrix, while ZrO2-SiO2-SG possessed the SiO2 support with a mesoporous structure, with an average pore size of ~7 nm and a surface area of 418 m2/g. The catalysts both exhibited excellent catalytic activity and stable performance in the esterification of oleic acid. Besides non-sulfated zirconia, sulfated zirconia catalysts other than traditional H2SO4-ZrO2 were also developed as solid acid catalysts for biodiesel production. Two sulfur-containing strong acids, chlorosulfonic acid (HClSO3) and (NH4)2SO4, were employed to acidify ZrO2, and two sulfated zirconia catalysts were prepared accordingly, namely HClSO3-ZrO2 and S-ZrO2. They were characterized by SEM, EDX, XRD, BET, IR, TGA and NH3-TPD. Comparing with H2SO4-ZrO2, HClSO3-ZrO2 and S-ZrO2 contained higher sulfur content and more acid sites. More importantly, both HClSO3-ZrO2 and S-ZrO2 demonstrated high catalytic activity and excellent durability in the esterification of oleic acid. It is known that consecutive esterification and transesterification reactions are suitable for direct biodiesel production and acetylation of glycerol enables the conversion of this biodiesel byproduct to a biofuel additive. Therefore, all the above mentioned catalysts were examined to compare their catalytic abilities in these reactions. Among the four catalysts, HClSO3-ZrO2 exhibited the highest catalytic activity in both reactions under optimal conditions. The thesis work here described the preparation and characterization of four types of ZrO2-based solid acid catalysts. Their catalytic activities were thoroughly investigated upon the several essential steps in biodiesel production. In addition, the synthesis condition-activity relation was studied and the synthesis and reaction conditions were delicately tuned.
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Kourieh, Reem. "Synthèse et caractérisation de catalyseurs de type oxydes mixtes pour des applications environnementales." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00993106.

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Ce travail est en relation avec la thématique "Chimie Verte" en particulier, le rôle de la catalyse,l'utilisation des matières premières renouvelables et l'élimination des produits nocifs.- Quatre échantillons commerciaux de zircone tungstatée de Mel-Chemicals.- deux séries de zircone tungstatée préparées par deux méthodes différentes avec une teneuren WO3 de 1 à 20 % en masse.- des oxydes binaires tels que WO3-ZrO2, B2O3-ZrO2, Al2O3-ZrO2, Ga2O3-ZrO2 et In2O3-ZrO2.- des oxydes binaires tels que WO3-Me2O3 (Me = B, Al, Ga et In) et finalement des oxydesternaires WO3/(Me2O3-ZrO2) (Me = B, Al, Ga et In) ont été étudiés et préparés lors de cettethèse.La performance catalytique de ces catalyseurs a été évaluée dans l'hydrolyse de la cellobiose, ladéshydratation du fructose et la réduction catalytique sélective des NOx. Les propriétés acides etredox de surface ont été corrélées aux performances catalytiques. En général, la conversion totale est liée à l'acidité des catalyseurs. Les catalyseurs les plus sélectifs pour la déshydratation du fructose et en deNOx sont ceux présentant une acidité modérée.
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Book chapters on the topic "Zirconia-based acid catalysts"

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Belkadhi, Itidel, Mohamed Achref Bouabdellah, Lassaad Ben Hammouda, and Zouhaier Ksibi. "Catalytic Wet Air Oxidation of Parahydroxybenzoic Acid by Catalysts Based on Zirconia." In Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions, 237–39. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70548-4_76.

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Pizzio, Luis, Patricia Vázquez, Carmen Cáceres, and Mirta Blanco. "Catalysts based on heteropoly acids supported on zirconia." In Studies in Surface Science and Catalysis, 953–58. Elsevier, 2000. http://dx.doi.org/10.1016/s0167-2991(00)80321-3.

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