Bibliografie tematiche / CO/CO2 hydrogenation

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Letteratura scientifica selezionata sul tema "CO/CO2 hydrogenation"

Autore: Grafiati
Pubblicato: 1 marzo 2025

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Articoli di riviste sul tema "CO/CO2 hydrogenation"

1

Li, Meng, e Dong Ding. "(Invited) Tuning Selective CO2 Electrohydrogenation Under Mid Temperature and Pressure". ECS Meeting Abstracts MA2024-01, n. 37 (9 agosto 2024): 2184. http://dx.doi.org/10.1149/ma2024-01372184mtgabs.

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To address rising environmental concerns and energy challenges, it is highly desirable to develop green technologies for a sustainable future. Hydrogenation reactions are essential processes in the chemical industry, giving access to a variety of valuable compounds. Electrochemical CO2 hydrogenation using renewable electricity is considered one of the most promising pathways to reach the environmental economics. Among various electrochemical devices, a solid state electrolyzer working at intermediate temperatures has the advantages of high reaction rates and low overpotentials. As CO2 molecules is quite stable, it is critical to develop electrocatalysts with high activity to reduce electricity engagement. Also, CO2 hydrogenation has multiple pathways which normally results in low selectivity for a target product. A tunable electrocatalyst with high selectivity to different products is desirable for CO2 conversion reactions. Heterostructured nanomaterials attracts great attentions in electrochemical systems. With careful design, they can show very high activity and selectivity towards an electrochemical reaction pathway. In this work, we combine theoretical simulations, including density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations, with experimental methods (characterizations and electrochemical measurements) for rational design of highly efficient heterostructured nanomaterials for CO2 hydrogenations. We studied the strong metal-support interaction (SMSI) in a doped CeO2 supported noble metal nanoparticles (NPs) system using theoretical calculations. The results indicate that SMSI largely depends on chemical conditions of the support and particle size of dispersed metal NPs. By tuning the SMSI, we can successfully change the catalytic activity and selectivity towards CO2 hydrogenation reactions. Based on these findings, we designed tunable heterostructured nanomaterials for efficient hydrogenation reactions at intermediate temperatures. These predictions were further confirmed by experimental method. By using a combination of high-throughput theoretical calculations and electrochemical measurements, we successfully developed highly active catalysts for electrochemical CO2 hydrogenation reactions. This framework is also applicable to other electrochemical systems using heterostructured materials.
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2

Konsolakis, Michalis, Maria Lykaki, Sofia Stefa, Sόnia A. C. Carabineiro, Georgios Varvoutis, Eleni Papista e Georgios E. Marnellos. "CO2 Hydrogenation over Nanoceria-Supported Transition Metal Catalysts: Role of Ceria Morphology (Nanorods versus Nanocubes) and Active Phase Nature (Co versus Cu)". Nanomaterials 9, n. 12 (6 dicembre 2019): 1739. http://dx.doi.org/10.3390/nano9121739.

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In this work we report on the combined impact of active phase nature (M: Co or Cu) and ceria nanoparticles support morphology (nanorods (NR) or nanocubes (NC)) on the physicochemical characteristics and CO2 hydrogenation performance of M/CeO2 composites at atmospheric pressure. It was found that CO2 conversion followed the order: Co/CeO2 > Cu/CeO2 > CeO2, independently of the support morphology. Co/CeO2 catalysts demonstrated the highest CO2 conversion (92% at 450 °C), accompanied by 93% CH4 selectivity. On the other hand, Cu/CeO2 samples were very selective for CO production, exhibiting 52% CO2 conversion and 95% CO selectivity at 380 °C. The results obtained in a wide range of H2:CO2 ratios (1–9) and temperatures (200–500 °C) are reaching in both cases the corresponding thermodynamic equilibrium conversions, revealing the superiority of Co- and Cu-based samples in methanation and reverse water-gas shift (rWGS) reactions, respectively. Moreover, samples supported on ceria nanocubes exhibited higher specific activity (µmol CO2·m−2·s−1) compared to samples of rod-like shape, disclosing the significant role of support morphology, besides that of metal nature (Co or Cu). Results are interpreted on the basis of different textural and redox properties of as-prepared samples in conjunction to the different impact of metal entity (Co or Cu) on CO2 hydrogenation process.
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Priyadarshani, Nilusha, Bojana Ginovska, J. Timothy Bays, John C. Linehan e Wendy J. Shaw. "Photoswitching a molecular catalyst to regulate CO2 hydrogenation". Dalton Transactions 44, n. 33 (2015): 14854–64. http://dx.doi.org/10.1039/c5dt01649e.

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4

Quan, Fengjiao, Guangming Zhan, Chengliang Mao, Zhihui Ai, Falong Jia, Lizhi Zhang, Honggang Gu e Shiyuan Liu. "Efficient light-driven CO2 hydrogenation on Ru/CeO2 catalysts". Catalysis Science & Technology 8, n. 24 (2018): 6503–10. http://dx.doi.org/10.1039/c8cy01787e.

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Wang, Yushan, Mengting Yu, Xinyi Zhang, Yujie Gao, Jia Liu, Ximing Zhang, Chunxiao Gong, Xiaoyong Cao, Zhaoyang Ju e Yongwu Peng. "Density Functional Theory Study of CO2 Hydrogenation on Transition-Metal-Doped Cu(211) Surfaces". Molecules 28, n. 6 (22 marzo 2023): 2852. http://dx.doi.org/10.3390/molecules28062852.

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Abstract (sommario):
The massive emission of CO2 has caused a series of environmental problems, including global warming, which exacerbates natural disasters and human health. Cu-based catalysts have shown great activity in the reduction of CO2, but the mechanism of CO2 activation remains ambiguous. In this work, we performed density functional theory (DFT) calculations to investigate the hydrogenation of CO2 on Cu(211)-Rh, Cu(211)-Ni, Cu(211)-Co, and Cu(211)-Ru surfaces. The doping of Rh, Ni, Co, and Ru was found to enhance CO2 hydrogenation to produce COOH. For CO2 hydrogenation to produce HCOO, Ru plays a positive role in promoting CO dissociation, while Rh, Ni, and Co increase the barriers. These results indicate that Ru is the most effective additive for CO2 reduction in Cu-based catalysts. In addition, the doping of Rh, Ni, Co, and Ru alters the electronic properties of Cu, and the activity of Cu-based catalysts was subsequently affected according to differential charge analysis. The analysis of Bader charge shows good predictions for CO2 reduction over Cu-based catalysts. This study provides some fundamental aids for the rational design of efficient and stable CO2-reducing agents to mitigate CO2 emission.
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Lykaki, Maria, Sofia Stefa, Georgios Varvoutis, Vassilios D. Binas, George E. Marnellos e Michalis Konsolakis. "Comparative Assessment of First-Row 3d Transition Metals (Ti-Zn) Supported on CeO2 Nanorods for CO2 Hydrogenation". Catalysts 14, n. 9 (11 settembre 2024): 611. http://dx.doi.org/10.3390/catal14090611.

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Herein, motivated by the excellent redox properties of rod-shaped ceria (CeO2-NR), a series of TM/CeO2 catalysts, employing the first-row 3d transition metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) as active metal phases, were comparatively assessed under identical synthesis and reaction conditions to decipher the role of active metal in the CO2 hydrogenation process. Notably, a volcano-type dependence of CO2 hydrogenation activity/selectivity was disclosed as a function of metal entity revealing a maximum for the Ni-based sample. Ni/CeO2 is extremely active and fully selective to methane (YCH4 = 90.8% at 350 °C), followed by Co/CeO2 (YCH4 = 45.2%), whereas the rest of the metals present an inferior performance. No straightforward relationship was disclosed between the CO2 hydrogenation performance and the textural, structural, and redox properties, whereas, on the other hand, a volcano-shaped trend was established with the relative concentration of oxygen vacancies and partially reduced Ce3+ species. The observed trend is also perfectly aligned with the previously reported volcano-type dependence of atomic hydrogen adsorption energy and CO2 activation as a function of 3d-orbital electron number, revealing the key role of intrinsic electronic features of each metal in conjunction to metal–support interactions.
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7

Li, Xiuping, Jiaqi Wang, Bolin Yin, Kaihong Liu, Jingjing Zhao, Bo Jiang e Hexing Li. "Plasmonic Cu-supported amorphous RuP for efficient photothermal CO2 hydrogenation to CO". RSC Advances 15, n. 3 (2025): 1658–64. https://doi.org/10.1039/d4ra07361d.

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8

Liu, Miao, Yanhui Yi, Li Wang, Hongchen Guo e Annemie Bogaerts. "Hydrogenation of Carbon Dioxide to Value-Added Chemicals by Heterogeneous Catalysis and Plasma Catalysis". Catalysts 9, n. 3 (18 marzo 2019): 275. http://dx.doi.org/10.3390/catal9030275.

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Abstract (sommario):
Due to the increasing emission of carbon dioxide (CO2), greenhouse effects are becoming more and more severe, causing global climate change. The conversion and utilization of CO2 is one of the possible solutions to reduce CO2 concentrations. This can be accomplished, among other methods, by direct hydrogenation of CO2, producing value-added products. In this review, the progress of mainly the last five years in direct hydrogenation of CO2 to value-added chemicals (e.g., CO, CH4, CH3OH, DME, olefins, and higher hydrocarbons) by heterogeneous catalysis and plasma catalysis is summarized, and research priorities for CO2 hydrogenation are proposed.
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9

Lu, Bowen, Huiying Sang, Liang Liu, Zhijian Yu, Yaqin Guo e Yongqing Xu. "The Synergistic Effect of CeO2 and Micron-Cu Enhances the Hydrogenation of CO2 to CO". Processes 12, n. 9 (6 settembre 2024): 1912. http://dx.doi.org/10.3390/pr12091912.

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The catalytic applications of micron Cu powder are limited due to its large particle size and small specific surface area. Modifying micro-Cu powder to achieve a high catalytic performance is a challenge in the application of micron copper. In this work, micro-Cu was used to synthesize a CeO2–Cu catalyst, and the phase composition and surface pore structure were analyzed using XRD, BET, etc. The CO2 hydrogenation performance of the CeO2–Cu catalyst was analyzed in comparison with CeO2 and Cu, and we found that the CeO2–Cu catalyst exhibited a synergistic effect between Cu and cerium, resulting in a much higher hydrogenation performance at 500 °C than CeO2 or Cu alone. H2-TPR and TEM characterization revealed that the CeO2–Cu catalyst formed interfacial interactions with a relatively large Ce–Cu interface, where cerium oxide could promote the reduction of CuO and lower the reduction temperature. Additionally, cerium oxide formed a confinement structure for Cu, and the CeO2–Cu catalyst exhibited a higher oxygen vacancy concentration, thereby promoting the CO2 hydrogenation performance. Cu–CeO2 interaction provides valuable insights into the catalytic application of micron Cu powder.
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Morozova, O. S., A. N. Streletskii, I. V. Berestetskaya e A. B. Borunova. "Co and Co2 hydrogenation under mechanochemical treatment". Catalysis Today 38, n. 1 (ottobre 1997): 107–13. http://dx.doi.org/10.1016/s0920-5861(97)00044-8.

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Più fonti

Tesi sul tema "CO/CO2 hydrogenation"

1

Ji, Qinqin. "The synthesis of higher alcohols from CO2 hydrogenation with Co, Cu, Fe-based catalysts". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF023/document.

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Abstract (sommario):
Le CO2 est une source de carbone propre pour les réactions chimiques, nombreux chercheurs ont étudié l'utilisation du CO2. Les alcools supérieurs sont des additifs de carburant propres. La synthèse des alcools supérieurs à partir de l'hydrogénation du CO a également été étudiée par de nombreux chercheurs, mais il existe peu de littératures sur la synthèse des alcools supérieurs à partir de l'hydrogénation du CO2, qui est une réaction complexe et difficile. Les catalyseurs utilisés pour la synthèse des alcools supérieurs nécessitent au moins deux phases actives et une bonne synergie. Dans notre étude, nous avons étudié les catalyseurs spinelle basés sur Co. Cu. Fe et l'effet des supports (CNTs et TUD-1) et celui des promoteurs (K, Na, Cs) à la réaction de HAS. Nous avons trouvé que le catalyseur CuFe-précurseur-800 est favorable pour la synthèse d'hydrocarbures en C2+ et d'alcools supérieurs. Dans l'hydrogénation du CO2, Co agit comme catalyseur de méthanisation plutôt que comme catalyseur FT, en raison du mécanisme de réaction différent entre l'hydrogénation du CO et celle du CO2. Afin d'inhiber la formation d'hydrocarbures de quantités importante, il est préférable de choisir des catalyseurs sans Co dans la réaction d'hydrogénation du CO2. En comparant les fonctions des CNT et du TUD-1, nous avons constaté que le CNT est un support parfait pour la synthèse de produits à longue chaîne (alcools supérieurs et hydrocarbures C2+). Le support TUD-1 est plus adapté à la synthèse de produits à un seul carbone (méthane et méthanol) .L'addition d'alcalis en tant que promoteurs conduit non seulement à augmenter la conversion de CO2 et H2, mais augmente également la sélectivité des produits visés fortement, des alcools supérieurs. Le catalyseur 0.5K30CuFeCNTs possède une productivités les plus élevées (370.7 g ∙ kg-1 ∙ h-1) d'alcools supérieurs à 350 ° C et 50 bar
CO2 is a clean carbon source for the chemical reactions, many researchers have studied the utilization of CO2. Higher alcohols are clean fuel additives. The synthesis of higher alcohols from CO hydrogenation has also been studied by many researchers, but there are few literatures about the synthesis of higher alcohols from CO2 hydrogenation, which is a complex and difficult reaction. The catalysts that used for higher alcohols synthesis need at least two active phases and goodcooperation. In our study, we tested the Co. Cu. Fe spinel-based catalysts and the effect of supports (CNTs and TUD-1) and promoters (K, Na, Cs) to the HAS reaction. We found that catalyst CuFe-precursor-800 is beneficial for the synthesis of C2+ hydrocarbons and higher alcohols. In the CO2 hydrogenation, Co acts as a methanation catalyst rather than acting as a FT catalyst, because of the different reaction mechanism between CO hydrogenation and CO2 hydrogenation. In order to inhibit the formation of huge amount of hydrocarbons, it is better to choose catalysts without Co in the CO2 hydrogenation reaction. Compared the functions of CNTs and TUD-1, we found that CNTs is a perfect support for the synthesis of long-chain products (higher alcohols and C2+ hydrocarbons). The TUD-1 support are more suitable for synthesis of single-carbon products (methane and methanol).The addition of alkalis as promoters does not only lead to increase the conversion of CO2 and H2, but also sharply increased the selectivity to the desired products, higher alcohols. The catalyst 0.5K30CuFeCNTs owns the highest productivities (370.7 g∙kg-1∙h-1) of higher alcohols at 350 °C and 50 bar
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Yao, Libo. "Sustainable, energy-efficient hydrogenation processes for selective chemical syntheses". University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1626172267871778.

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Zhang, Long. "In-Situ Infrared Studies of Adsorbed Species in CO2 Capture and Green Chemical Processes". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1481213980572202.

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4

Corda, Massimo. "Catalyst Design and Mechanistic Insights into COx Hydrogenation to Methanol and Light Olefins". Electronic Thesis or Diss., Université de Lille (2022-....), 2024. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2024/2024ULILR037.pdf.

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Abstract (sommario):
L'augmentation de la concentration de CO2 atmosphérique présente des défis environnementaux significatifs et souligne l'urgence de développer des procédés chimiques durables. Une approche prometteuse pour aborder ces problèmes est la conversion catalytique du CO2 en produits chimiques à valeur ajoutée, tels que le méthanol et les oléfines légères. Cette thèse se concentre sur le développement de catalyseurs pour la synthèse de méthanol et la synthèse d'oléfines légères à partir de CO2 par médiation de méthanol. De plus, l'hydrogénation du CO médiée par le méthanol en oléfines légères est également étudiée: le CO peut être considéré comme une alternative au CO2, car il peut être produit par la réaction du gaz à l'eau inverse. Les travaux rapportés dans cette thèse fournissent de nouvelles perspectives sur la conception de catalyseurs pour l'hydrogénation de COx en méthanol ou en oléfines légères, en suggérant de nouvelles stratégies pour améliorer la sélectivité des produits. De plus, la thèse fait progresser la compréhension des aspects mécanistiques de ces réactions. Pour l'hydrogénation du CO2 en méthanol, le catalyseur commercial CuO-ZnO-Al2O3 a été promu avec des halogènes (Br, Cl, I) pour améliorer la sélectivité au méthanol. Il a été observé que le Br permettait d'améliorer la sélectivité de 10 % par rapport au catalyseur initial. Une analyse cinétique a montré que le Br entraînait la suppression de la réaction de conversion inverse de l'eau en gaz et de la réaction de décomposition du méthanol, toutes deux responsables de la production parallèle de CO. Pour l'hydrogénation du CO2 en oléfines légères médiée par le méthanol, une série de catalyseurs bifonctionnels basés sur des oxydes de Zn, In, Mn, Cr ou Ga et différents zéolithes SAPO-34 a été étudiée. L'analyse des corrélations sélectivité-conversion a permis d'élucider les fonctions de chaque composant du catalyseur. Il a été découvert que la sélectivité aux oléfines légères au sein des fractions d'hydrocarbures dépendait finalement du composant zéolithique et diminuait en fonction du rendement en hydrocarbures. Le composant catalyseur à base d'oxyde métallique était responsable de la conversion du CO2, de la sélectivité globale aux hydrocarbures et au CO. La morphologie et l'acidité du SAPO-34 ont été identifiées comme des descripteurs majeurs de la sélectivité aux oléfines légères sans CO dans l'hydrogénation du CO2 sur des catalyseurs bifonctionnels. Enfin, pour la synthèse d'oléfines légères médiée par le méthanol à partir de gaz de synthèse, ce travail a étudié l'activité d'un catalyseur bifonctionnel composé de nanoparticules d'argent supportées mélangées à la zéolithe SAPO-34. Les catalyseurs résultants ont montré une sélectivité plus élevée aux oléfines légères par rapport à un catalyseur conventionnel oxyde-zéolithe. Il a été observé que la réaction est sensible à la structure, et la taille des particules d'argent influence la sélectivité aux oléfines légères
The increasing concentration of atmospheric CO2 presents significant environmental challenges and emphasizes the urgency for sustainable chemical processes. One promising approach to address this issues is the catalytic conversion of CO2 into value-added chemicals, such as methanol and light olefins. This thesis focuses on the catalyst development for the methanol synthesis and the methanol-mediated light olefins synthesis from CO2. Moreover, the methanol-mediated CO hydrogenation to light olefins is also studied: CO can be considered as an alternative to CO2, as it can be produced by the Reverse Water Gas Shift reaction. The work reported in this thesis provides new insights into catalyst design for the COx hydrogenation to methanol or light olefins, suggesting new strategies to improve product selectivity. Additionally, the thesis advances the understanding of mechanistic aspects of these reactions. For the CO2 hydrogenation to methanol, the commercial CuO-ZnO-Al2O3 catalyst was promoted with halogens (Br, Cl, I), to improve selectivity to methanol. It was observed that Br allowed to improve the selectivity of 10 % compared to the pristine catalyst. A kinetic analysis showed that Br caused the suppression of the Reverse Water Gas Shift reaction and of the methanol decomposition reaction, both responsible of the parallel production of CO. For the methanol-mediated CO2 hydrogenation to light olefins, a series of bifunctional catalysts based on oxides of Zn, In, Mn, Cr, or Ga and different SAPO-34 zeolites were studied. The analysis of the selectivity-conversion correlations allowed to elucidate the functions of each catalyst component. It was uncovered that the selectivity to LO within hydrocarbon fractions depended ultimately on the zeolite component and decreased as a function of hydrocarbon yield. The metal-oxide catalyst component was responsible for the CO2 conversion, overall hydrocarbon and CO selectivity. The SAPO-34 morphology and acidity were identified as major descriptors of the CO-free LO selectivity in the CO2 hydrogenation over bifunctional catalysts. Finally, for the methanol-mediated synthesis of light olefins from syngas, this work studied the activity of a bifunctional catalyst composed by supported silver nanoparticles mixed with SAPO-34 zeolite. The resulting catalysts exhibited higher selectivity to light olefins compared to a conventional oxide-zeolite catalyst. It was observed that the reaction is structure-sensitive, and the silver particle size influences the selectivity to light olefins
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5

Peng, Lu. "Metal Nanoparticles Wrapped on Defective Nitrogen-doped Graphitic Carbons as Highly Selective Catalysts for C02 Hydrogenation". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/172329.

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[ES] Teniendo en cuenta el agotamiento de los combustibles fósiles y la creciente concentración de CO2 en la atmósfera, la hidrogenación de CO2 es una forma prometedora de convertir el CO2 en productos químicos y combustibles de carbono de alto valor añadido. Considerando la gran influencia del tamaño de partícula, la composición química, la naturaleza del soporte y las condiciones de operación sobre el comportamiento catalítico de los catalizadores, se han desarrollado una serie de catalizadores para la hidrogenación de CO2 basados en metales abundantes no nobles y polisacáridos naturales como precursores del grafeno. En la presente tesis doctoral, las especies metálicas soportadas sobre una matriz de carbono grafítico defectuosa, con diferentes tamaños de partículas, muestran diferente actividad catalítica y selectividad para la hidrogenación de CO2. Se prepararon, de forma controlada, nanopartículas de aleaciones de Co y Co-Fe soportadas en grafenos dopados con N defectuosos, con una amplia distribución de tamaño de nanopartículas, para la reacción de Sabatier, presentando una selectividad a metano superior al 90% con valores de conversión de CO2 superiores al 85%. En el caso de un solo metal, Co o Fe, y sus aleaciones en forma de "clusters" y pequeñas nanopartículas soportadas en el mismo material, la selectividad de la hidrogenación de CO2 cambia a CO, en lugar de metano, obteniéndose un valor del 98 % y alcanzando una conversión de CO2 del 56%. Conviene resaltar que, los catalizadores basados en "clusters" de aleaciones de metal con una carga de metal incluso por debajo del 0.2 % en peso, exhiben una mayor selectividad y rendimiento que los que tienen nanopartículas de aleaciones de Co-Fe más grandes que varían de 1 a 4 nm y una carga de metal más alta en una composición similar. Siguiendo la línea de investigación de hidrogenación de CO2, se desarrollaron una serie de nanopartículas de aleaciones de Co-Fe soportadas sobre grafenos dopados con N defectuosos con distribución de tamaño de nanopartículas controlada en el rango de 7-17 nm, obteniendo una selectividad hacia hidrocarburos C2+ alrededor del 45% y una conversión del CO2 cercana al 60%. Además, se realizó un estudio comparativo de la actividad catalítica de catalizadores similares basados en Co-Fe con promotores e inhibidores para la hidrogenación de CO2, observando su influencia en la conversión y selectividad de CO2. Finalmente, además de los catalizadores basados en Co-Fe, también se han preparado catalizadores basados en Cu-ZnO mediante un método de dos pasos. Estas nanopartículas de Cu-ZnO soportadas sobre grafeno defectuoso dopado con N exhiben una alta selectividad hacia la conversión de CO2 a metanol.
[CA] Tenint en compte l'esgotament dels combustibles fòssils i la creixent concentració de CO2 en l'atmosfera, la hidrogenació de CO2 és una forma prometedora de convertir el CO2 en productes químics i combustibles de carboni d'alt valor afegit. Considerant la gran influència de la grandària de partícula, la composició química, la naturalesa del suport i les condicions d'operació sobre el comportament catalític dels catalitzadors, s'han desenvolupat una sèrie de catalitzadors per a la hidrogenació de CO2 basats en metalls abundants no nobles i polisacàrids naturals com a precursors del grafé. En la present tesi doctoral, les espècies metàl·liques suportades sobre una matriu de carboni grafític defectuosa, amb diferents grandàries de partícules, mostren diferent activitat catalítica i selectivitat per a la hidrogenació de CO2. Es van preparar, de manera controlada, nanopartícules d'aliatges de Co i Co-Fe suportades en grafens dopats amb N defectuosos, amb una àmplia distribució de grandària de nanopartícules, per a la reacció de Sabatier, presentant una selectivitat a metà superior al 90% amb valors de conversió de CO2 superiors al 85%. En el cas d'un sol metall, Co o Fe, i els seus aliatges en forma de "clústers" i xicotetes nanopartícules suportades en el mateix material, la selectivitat de la hidrogenació de CO2 canvia a CO, en lloc de metà, obtenint-se un valor del 98% i aconseguint una conversió de CO2 del 56%. Convé ressaltar que, els catalitzadors basats en "clústers" d'aliatges de metall amb una càrrega de metall fins i tot per davall del 0.2% en pes, exhibeixen una major selectivitat i rendiment que els que tenen nanopartícules d'aliatges de Co-Fe més grans que varien d'1 a 4 nm i una càrrega de metall més alta en una composició similar. Seguint la línia d'investigació d'hidrogenació de CO2, es van desenvolupar una sèrie de nanopartícules d'aliatges de Co-Fe suportades sobre grafens dopats amb N defectuosos amb distribució de grandària de nanopartícules controlada en el rang de 7-17 nm, obtenint una selectivitat cap a hidrocarburs C2+ al voltant del 45% i una conversió del CO2 pròxima al 60%. A més, es va realitzar un estudi comparatiu de l'activitat catalítica de catalitzadors similars basats en Co-Fe amb promotors i inhibidors per a la hidrogenació de CO2, observant la seua influència en la conversió i selectivitat de CO2. Finalment, a més dels catalitzadors basats en Co-Fe, també s'han preparat catalitzadors basats en Cu-ZnO mitjançant un mètode de dos passos. Aquestes nanopartícules de Cu-ZnO suportades sobre grafé defectuós dopat amb N exhibeixen una alta selectivitat cap a la conversió de CO2 a metanol.
[EN] Considering the depletion of fossil fuels and the increasing atmospheric CO2 concentration, CO2 hydrogenation is a promising way to convert CO2 into value-added carbon-containing chemicals and fuels. Taking into account the significant influences of the particle size, chemical composition, nature of the support, and operation conditions on the catalytic performance of catalysts, a series of catalysts for CO2 hydrogenation have been developed based on the use of abundant non-noble metals and natural polysaccharides as graphene precursors. In the present PhD Thesis, metal species supported on defective graphitic carbon matrix with different particle sizes show different catalytic activity and selectivity for CO2 hydrogenation. Under effective control, Co and Co-Fe alloy nanoparticles wrapped on defective N-doped graphenes with a broad nanoparticle size distribution were prepared and performed for the Sabatier reaction, exhibiting a selectivity to methane over 90 % at CO2 conversion values over 85 %. In the case of single Co or Fe metal and their alloys in the form of clusters and small nanoparticles wrapped on the same support, the selectivity for CO2 hydrogenation shifts to CO, rather than methane, reaching a conversion of 56 % with 98 % CO selectivity. It is worth noting that the metal alloy clusters-based catalysts with the metal loading even below 0.2 wt.% exhibit a higher selectivity and better performance than the ones with larger Co-Fe alloy nanoparticles ranging from 1-4 nm and higher metal loading in a similar composition. Following the research line for CO2 hydrogenation, a series of Co-Fe alloy nanoparticles supported on defective N-doped graphenes with controlled nanoparticle size distribution in the range of 7-17 nm are developed, obtaining a selectivity towards C2+ hydrocarbons about 45% with a CO2 conversion close to 60%. In addition, a comparative catalytic activity of similar Co-Fe-based catalysts with promoters and poison has been studied for CO2 hydrogenation to observe their influence on CO2 conversion and selectivity. Finally, besides Co-Fe-based catalysts, Cu-ZnO-based catalysts have also been prepared by a two-step method. These Cu-ZnO nanoparticles supported on N-doped defective graphene exhibit a high selectivity for CO2 conversion to methanol.
Peng, L. (2021). Metal Nanoparticles Wrapped on Defective Nitrogen-doped Graphitic Carbons as Highly Selective Catalysts for C02 Hydrogenation [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172329
TESIS
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Ralston, Walter Thomas. "Hydrogenation Reactions of CO and CO2| New Insights through In Situ X-ray Spectroscopy and Chemical Transient Kinetics Experiments on Cobalt Catalysts". Thesis, University of California, Berkeley, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10282649.

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The catalytic hydrogenations of CO and CO2 to more useful chemicals is not only beneficial in producing more valuable products and reducing dependence on fossil fuels, but present a scientific challenge in how to control the selectivity of these reactions. Using colloidal chemistry techniques, a high level of control over the synthesis of nanomaterials can be achieved, and by exploiting this fact a simple model system can be realized to understand the reaction of CO and CO2 on a molecular level. Specifically, this dissertation focuses on understanding cobalt materials for the conversion of CO and CO2 into more useful, valuable chemicals.

Colloidally prepared cobalt nanoparticles with a narrow size distribution were supported in mesoporous SiO2 and TiO2 to study the effect of the support on the Co catalyzed hydrogenation of CO and CO2. The 10nm Co/SiO2 and Co/TiO2 catalysts were tested for CO and CO2 hydrogenation at 5 bar with a ratio to hydrogen of 1:2 and 1:3, respectively. In addition, the effect of Co oxidation state was studied by using different reduction pretreatment temperatures (250°C and 450°C). The results showed that for both hydrogenation reactions, Co/TiO2 had a high activity at both reduction temperatures compared to Co/SiO2. However, unlike Co/SiO2 which showed higher activity after 450°C reduction, Co/TiO2 had a higher activity after reduction at 250°C. Through synchrotron x-ray spectroscopy, it was concluded that the TiO2 was wetting the Co particle at higher reduction temperatures and dewetting at lower reduction temperatures. In addition to the wetting, CoO was observed to be the surface species on Co/TiO2 catalyst after reduction at low temperatures, which catalyzed both CO and CO2 hydrogenation reactions with higher activity than the Co metal obtained after reduction at 450°C.

Classical steady-state measurements are limited in so much as they are often unable to provide information on individual reaction steps in complex reaction pathways. To attempt to circumvent this, a chemical transient kinetics (CTK) reactor was designed and built. Verification of the reactor was performed by evaluating a catalyst from the literature and confirming the results. A CoMgO catalyst was used to accomplish this, and our original findings show that at short time scales steric hindrances at the surface may push the product distribution towards olefinic rather than branched compounds.

Continuing work on the CTK, two distinct particle sizes of Co nanoparticles were synthesized and tested under atmospheric conditions (H2:CO = 2:1) on the transient reactor. 4.3 nm Co and 9.5 nm Co were supported on MCF-17 to study the previously observed size effect, where Co nanoparticles lose activity at smaller sizes. It was found that indeed, the 4.3 nm Co are less active because they contain less CO dissociation sites, which are necessary for populating the surface with carbon monomers and spurring subsequent chain growth. The specific CO dissociation site was identified as the Co (221) step, of which larger Co particles have more and smaller Co particles have less.

To investigate the nature of the MnO / Co3O4 interface, an in situ study using synchrotron radiation was undertaken. A sample of 6nm MnO nanoparticles loaded on mesoporous Co3O4 was studied with ambient pressure x-ray photoelectron spectroscopy, soft x-ray absorption spectroscopy at the Mn and Co L edges, and scanning transmission x-ray microscopy. X-ray measurements show that under reducing conditions of CO + H2, the MnO nanoparticles wet the Co surface until it is completely covered by a layer of MnO. Through the combination of techniques, it is shown that the system is catalytic active at the low pressures studied, and that the nature of the interface between MnO and Co3O4 is highly dependent on the temperature and gaseous environment it is prepared in. (Abstract shortened by ProQuest.)

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Barrios, Medina Alan Josue. "Synthèse Directe d'Oléfines Légères par des Réactions d'Hydrogénation du CO et du CO2". Electronic Thesis or Diss., Centrale Lille Institut, 2021. http://www.theses.fr/2021CLIL0030.

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L'hydrogénation du CO et du CO2 sont une voie intéressante de conversion des matières premières non pétrolières et renouvelables tels que la biomasse, le plastique et les déchets organiques, en carburant et en produits chimiques. L'activité, la sélectivité vers la production d’oléfines légères et la stabilité sont des défis majeurs de ces réactions sur les catalyseurs à base de fer. Dans cette thèse, nous avons synthétisé différents catalyseurs à base de fer pour l'hydrogénation du CO et du CO2 afin d'obtenir des catalyseurs hautement sélectifs, actifs et stables. Pour l'hydrogénation du CO, SiO2 a été utilisée comme support tandis que pour la réaction d'hydrogénation du CO2, les catalyseurs supportés par de la ZrO2 ont présenté les résultats les plus encourageants. Les résultats sont appuyés sur l'expérimentation à haut débit (EHD) pour identifier parmi 27 promoteurs les plus efficaces pour la synthèse de FT en évaluant également les différentes tendances de sélectivité en la réaction FT. Les tests EHD nous ont permis d'identifier clairement Sn, Sb, Bi et Pb comme les promoteurs les plus prometteurs afin d'obtenir des catalyseurs de Fe avec une plus grande activité. Après, nous nous sommes concentrés sur l'étude des promoteurs Sb et Sn, sur la performance catalytique des catalyseurs à base de fer supportés sur SiO2, en utilisant une combinaison de techniques avancées et in-situ. Les images MET du catalyseur FeSn/SiO2 activé ont montré des nanoparticules de Sn hautement dispersées sur le support de silice. D'autre part, le catalyseur FeSb/SiO2 activé a montré une morphologie coeur-coquille. Plus petite quantité de dépôt de carbone détectée est cruciale pour une meilleure stabilité des catalyseurs promus par Sn- et Sb dans la réaction FT. Finalement, nous nous sommes concentrés sur l'identification des promoteurs pour les catalyseurs de fer supportés sur ZrO2 pour la réaction d’hydrogénation du CO2. Nous avons observé une nette augmentation de la vitesse de réaction pour les catalyseurs promus par le K et le Cs. L’EHD a clairement montré que la présence de K est essentielle pour obtenir une plus grande sélectivité en oléfines légères. En plus, le Mo, Cu, Cs, Ce et Ga ont été identifiés comme des promoteurs capables d’augmenter encore la sélectivité en oléfines. Le travail effectué au cours de cette thèse a permis de concevoir de nouveaux catalyseurs pour la réaction d'hydrogénation du CO et du CO2 qui pourraient être facilement mis en oeuvre au niveau industriel. Les catalyseurs étudiés pour les deux réactions ont montré une amélioration de trois aspects clés : l'activité, la sélectivité et la stabilité
CO and CO2 Hydrogenation are an attractive way to convert non-petroleum and renewable feedstocks such as biomass, plastic and organic waste into fuels and chemicals. Activity, selectivity to light olefins and stability are major challenges of these reactions over Fe catalysts. In this thesis, we synthesized different iron-based catalysts for both CO and CO2 hydrogenation in order to get highly selective, active and stable catalysts. For CO hydrogenation SiO2 was used as support while for CO2 hydrogenation reaction ZrO2 supported catalysts presented the most encouraging results. We relied on High Throughput Experimentation (HTE) to identify among 27 promoters the most efficient ones for FT synthesis at the same time that different selectivity trends were evaluated. HTE tests allowed us to clearly identify Sn, Sb, Bi and Pb as the most promising promoters in order to obtain Fe catalysts with higher activity in FT synthesis. Then, we focused on studying the strong promoting effects of Sb and Sn on the catalytic performance of SiO2 supported iron Fischer Tropsch catalysts using a combination of advanced and in-situ techniques. TEM in the activated FeSn/SiO2 catalyst showed highly dispersed Sn nanoparticles on the silica support. On the other hand, activated FeSb/SiO2 catalyst showed a core-shell morphology. Additionally, smaller amount of carbon deposition detected is crucial for better stability of the Sn- and Sb-promoted catalysts in FT reaction. Finally, we focused on the identification of efficient promoters for ZrO2 supported iron catalysts in CO2 hydrogenation reaction. We observed the most pronounced increase in the reaction rate for the K and Cs promoted catalysts. HTE clearly showed that the presence of K was essential to achieve higher light olefin selectivity. Additionally, Mo, Cu, Cs, Ce and Ga were identified as possible promoters to further increase the selectivity of CO2 hydrogenation to this fraction. The work performed during this thesis allowed to design new catalysts for CO and CO2 hydrogenation reaction that could be easily implemented at industrial level. Catalysts studied for both reactions showed improvement three key aspects: activity, selectivity, and stability
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Patprom, Kanthika. "Optimisation d'un procédé de synthèse d'hydrocarbures liquides à partir d'un syngaz ex-biomasse et d'une source d'hydrogène renouvelable". Electronic Thesis or Diss., Lyon 1, 2024. http://www.theses.fr/2024LYO10295.

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Le sujet de cette thèse s'inscrit dans le cadre du processus Power and Biomass-to-Liquid (PBtL). En particulier, le syngaz issu de la biomasse (mélange CO+CO2+H2) peut être utilisé pour produire un brut de synthèse pouvant ensuite être transformé en différents carburants via la synthèse Fischer-Tropsch. Cependant, le syngaz issu de la biomasse a un faible rapport H/C, ce qui nécessite le recyclage ou même l'élimination du CO2 à la fin du procédé, ce qui a un impact négatif sur la valorisation globale du carbone dans la ressource. Le procédé PBtL consiste à ajouter de l'H2 par une unité d'électrolyse de l'eau pour ajuster le rapport H/C dans le syngaz, afin de mieux valoriser le carbone contenu dans la biomasse. Cette thèse se concentre sur l'étude cinétique de la conversion directe de mélanges H2/CO/CO2 en hydrocarbures via la synthèse Fischer-Tropsch sur un catalyseur Fe-K-Cu-La/Al2O3 supporté. L'un des principaux défis de cette réaction est sa faible sélectivité, car elle produit une large gamme d'hydrocarbures. Par conséquent, il est essentiel de comprendre l'effet de paramètres tels que les conditions opératoires sur la performance catalytique pour optimiser la productivité vers les produits souhaités. Dans ce travail, la performance catalytique de quatre catalyseurs différents avec le mélange H2/CO2 a été évaluée dans un réacteur à lit fixe à l'échelle du laboratoire, et le catalyseur Fe-K-Cu-La/Al2O3 a été identifié comme une option appropriée. Ensuite, l'étude expérimentale du catalyseur Fe-K-Cu-La/Al2O3 sous des mélanges H2/CO/CO2 a été réalisée dans différentes conditions opératoires, y compris la température, le temps de contact, la pression totale et la composition du syngaz, afin d'étudier leur impact sur la performance catalytique. Enfin, un modèle macro-cinétique semi-empirique décrivant la performance du catalyseur dans la plage de condition opératoire étudiée et tenant compte de la formation de toutes les principales espèces observées a été développé
The subject of this thesis is part of the Power and Biomass-to-Liquid (PBtL) process framework. In particular, biomass-derived syngas (CO+CO2+H2 mixture) can be used to produce liquid transportation fuels, such as gasoline, diesel, and jet fuel via Fischer-Tropsch synthesis. However, syngas from biomass has a low H/C ratio, requiring the recycling or even elimination of CO2 at the end of the process, which has a negative impact on the overall valorization of bio-based carbon. The PBtL process consists of adding H2 by a water electrolysis unit to adjust the H/C ratio in the syngas, aiming to better valorizing the carbon content of biomass. This thesis is focused on the kinetic study of direct conversion of H2/CO/CO2 mixtures towards hydrocarbons via Fischer-Tropsch synthesis over a supported Fe-K-Cu-La/Al2O3 catalyst. One of the main challenges of this reaction is its low selectivity, as it produces a wide range of hydrocarbons. Therefore, understanding the effect of parameters such as operating conditions on catalytic performance is essential for optimizing productivity toward desired products. In this work, the catalytic performance of four different catalysts under H2/CO2 mixtures has been evaluated in a lab-scale fixed-bed reactor, and the Fe-K-Cu-La/Al2O3 catalyst has been identified as a suitable option. Then the experimental study of Fe-K-Cu-La/Al2O3 catalyst under H2/CO/CO2 mixtures has been performed under various operating conditions, including temperature, contact time, total pressure, and syngas composition in order to investigate their impact on catalytic performance. Finally, a semi-empirical macro kinetic model that describes the performance of catalyst across the studied operating range and accounts for the formation of all major observed species has been developed
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Quezada, Maxwell Josias. "Hydrogénation catalytique de CO₂ en méthanol en lit fixe sous chauffage conventionnel et sous plasma à DBD ZSM-5 surface modification by plasma for catalytic activity improvement in the gas phase methanol-to-dimethylether reaction". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR12.

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L’objectif de cette thèse est de contribuer à l’optimisation de la production de méthanol par hydrogénation de CO₂ en synthétisant des nouveaux catalyseurs sous forme d’extrudés pour un usage industriel. Six catalyseurs à base de Cu et ZnO supportés sur de l’alumine et des ZSM-5 ont été préparés et testés. A 36 bar et sous chauffage conventionnel, le CuZnO/Al₂O₃ a montré le meilleur rendement en méthanol. Un procédé industriel basé sur ce catalyseur a été proposé et optimisé. L’influence de l’extraction de l’eau et du méthanol du milieu réactionnel en utilisant deux réacteurs en série au lieu d’un a été étudié et il a été trouvé que cela augmente le rendement en méthanol considérablement. Sous plasma à DBD et à 1 bar, le Cu/Al₂O₃ donne des meilleures conversions de CO₂, alors que le CuZnO/ZSM-5 montre des meilleurs rendements en méthanol. Cela a été attribuée à la conductivité ionique et à la constante diélectrique des matériaux
The objective of this thesis is to contribute to the optimisation of the production of methanol by hydrogenation of CO₂ by synthesising new catalysts in the form of extrudates for industrial use. In this regard, six Cu-ZnO based catalysts supported on alumina and ZSM-5 were prepared and tested. At 36 bar and under conventional heating, the CuZnO/Al₂O₃ showed the best methanol yield. An industrial process based on this catalyst has been proposed and optimised. The influence of extracting water and methanol from the reaction medium using two reactors in series instead of one was investigated and it was found to increase methanol yield considerably. Tests at atmospheric pressure and under DBD plasma showed that the Cu/Al₂O₃ gives better CO₂ conversions, while the CuZnO/ZSM-5 showed better methanol yields. This was attributed to the ionic conductivity and the dielectric constant of the catalysts
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Chew, Ly May [Verfasser], Martin [Gutachter] Muhler e Wolfgang [Gutachter] Grünert. "Catalytic hydrogenation of CO_2 and CO to short-chain hydrocarbons over iron nanoparticles supported on functionalized carbon nanotubes / Ly May Chew ; Gutachter: Martin Muhler, Wolfgang Grünert ; Fakultät für Chemie und Biochemie". Bochum : Ruhr-Universität Bochum, 2015. http://d-nb.info/1204257035/34.

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Capitoli di libri sul tema "CO/CO2 hydrogenation"

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Yang, Qingxin, e Evgenii V. Kondratenko. "Status of Catalyst Development for CO2 Hydrogenation to Platform Chemicals CH3OH and CO". In Green Chemistry and Sustainable Technology, 81–104. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8822-8_4.

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Panagiotopoulou, Paraskevi, e Xenophon E. Verykios. "Metal–support interactions of Ru-based catalysts under conditions of CO and CO2 hydrogenation". In Catalysis, 1–23. Cambridge: Royal Society of Chemistry, 2020. http://dx.doi.org/10.1039/9781788019477-00001.

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Braca, Giuseppe. "Mono Alcohols, Glycols, and their Ethers and Esters by CO Hydrogenation". In Oxygenates by Homologation or CO Hydrogenation with Metal Complexes, 1–88. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0874-4_1.

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Braca, Giuseppe. "Alcohols and Derivatives by Homologation with Syngas". In Oxygenates by Homologation or CO Hydrogenation with Metal Complexes, 89–190. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0874-4_2.

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Braca, Giuseppe. "Hydrocarbonylation of Aldehydes and their Derivatives". In Oxygenates by Homologation or CO Hydrogenation with Metal Complexes, 191–219. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0874-4_3.

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Holladay, Johnathan E., Todd A. Werpy e Danielle S. Muzatko. "Catalytic Hydrogenation of Glutamic Acid". In Proceedings of the Twenty-Fifth Symposium on Biotechnology for Fuels and Chemicals Held May 4–7, 2003, in Breckenridge, CO, 857–69. Totowa, NJ: Humana Press, 2004. http://dx.doi.org/10.1007/978-1-59259-837-3_70.

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Souma, Yoshie, e Masahiro Fujiwara. "Hydrogenation of Carbon Dioxide by Catalysts". In Carbon Dioxide Fixation and Reduction in Biological and Model Systems, 157–67. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198547822.003.0011.

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Abstract Huge amounts of CO2 have been emitted by the consumption of fossil fuel, accompanied by the development of industry. The total amounts of emitted CO2 from fossil fuels are assumed to be 19 x 109 ton year-’, of which 60 per cent are emitted from thermal power stations or factories. Although CO2 should be recovered and fixed in order to prevent global warming, at the same time, CO2 is an important carbon source to be reused as a chemical or fuel. Various methods are known for the fixation of CO2. However, a rapid conversion rate of CO2, which is comparable to the combustion rate of fossil fuel, is indispensable. From this viewpoint the hydrogenation of CO2 is expected to be the best method to fix huge amounts of CO2. Carbon dioxide is emitted in comparatively high concentrations from power stations, factories, and ironworks and is therefore suitable for recovery and recycling use. The concept of recycling technology for CO2 by hydrogenation is shown in Fig. 11.1. Although many reports of CO hydrogenation have been published for the synthesis of an alternative fuel after the oil crisis of the last decade (Fujimoto et al. 1988; Inui et al.1985; Liu et al. 1984), the study of CO2 hydrogenation is by no means sufficient. The research on CO2 hydrogenation is expected to be developed rapidly by referring to the results of CO hydrogenation.
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"Other Directions for FLP Hydrogenations". In A Primer in Frustrated Lewis Pair Hydrogenation: Concepts to Applications, 129–63. The Royal Society of Chemistry, 2021. http://dx.doi.org/10.1039/9781839162442-00129.

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This chapter described the application of the concept of FLPs in new and unexplored reactivity with dihydrogen beyond organic reductions. The use of this reactivity to generate radicals, effect transfer hydrogenations or dehydrogenation, and the applications of hydrogenation for small-molecule substrates such as CO, CO2 and N2 are considered. In addition, the relevance of FLP reactivity to enzymatic systems, supported FLP catalysts, solid-state reactivity, and heterogeneous catalysts is also considered. These additional directions of growth and applications of FLP–dihydrogen reactivity further affirm the potential of FLP chemistry as a new axiom of chemical reactivity.
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Cubeiro, M. L., G. Valderrama, M. R. Goldwasser, F. González-Jiménez, M. C. Da Silva e M. J. Pérez-Zurita. "Hydrogenation of CO and CO2 with K and Mn promoted iron catalysts". In Natural Gas Conversion IV, 231–36. Elsevier, 1997. http://dx.doi.org/10.1016/s0167-2991(97)80340-0.

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Loganathan, Sivachandiran, e Aymen Amine Assadi. "Nanomaterials for photocatalytic and cold plasma-catalytic hydrogenation of CO2 to CO, CH4, and CH3OH". In Nanomaterials for CO2 Capture, Storage, Conversion and Utilization, 353–73. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-822894-4.00012-5.

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Atti di convegni sul tema "CO/CO2 hydrogenation"

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Doty, F. David, Glenn N. Doty, John P. Staab e Laura L. Holte. "Toward Efficient Reduction of CO2 to CO for Renewable Fuels". In ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90362.

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Three major challenges — grid stability, domestic oil limitations, and climate change — could all be addressed simultaneously by using off-peak electrical energy to recycle CO2 into liquid fuels (such as gasoline, jet fuel, and diesel). Simulations have shown that recent innovations should make it practical to reduce CO2 to CO at over 66% of theoretical efficiency limits. When combined with other process advances, it would then be possible to synthesize most hydrocarbons and alcohols from point-source CO2 and clean off-peak grid energy (wind or nuclear) at system efficiencies in the range of 51–61%. Energy storage density in renewable, carbon-neutral kerosene is 44 MJ/kg, compared to ∼0.4 MJ/kg for Li-ion batteries. This process begins by electrolyzing water using clean energy to get the hydrogen required by the Reverse Water Gas Shift (RWGS) reactor and by a novel Renewable Fischer Tropsch Synthesis (RFTS) process. Off-peak grid energy averaged only $13/MWhr in the Minnesota hub in 2009. At such prices, the synthesized liquid fuels (“WindFuels”) should compete even when petroleum is only $50/bbl. Considerable effort over the past decade has been put into exploring high-temperature (HT) paths toward the production of renewable syngas (H2 + CO) that could lead to sustainable synthesis of liquid fuels; but competitive fuel production from these HT thermo-chemical routes still appears to be decades away. An alternative path — the RWGS reaction — utilizes much less aggressive conditions and should be much more practical. With low-cost hydrogen becoming available from off-peak wind and nuclear, efficient reduction of CO2 to CO becomes viable at moderate temperatures (750–1000 K) via the RWGS reaction. Challenges arise because of equilibrium limits imposed by the reaction thermodynamics below 800 K and because of competing methanation and coking reactions above 800 K to 1000 K, depending on the catalysts. Several promising sets of conditions and catalysts are being evaluated. To drive the reaction to the right, a multi-stage process is required with efficient separation processes. This in turn depends on advances in cost-effective gas-to-gas recuperators for relatively low pressures to limit parasitic methanation reactions. Another challenge may be passivation of the recuperator surfaces to minimize hydrogenation of the CO during the heat recovery. Preliminary simulations indicate reduction of CO2 to CO with about 2.2 MJ/kg-CO should be practical at commercial scale.
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2

Kelechi, F. M., e A. A. Aribisala. "Thermochemical Conversion of Microalgae: Challenges and Prospective of HTL Pathway for Algae Biorefinery". In SPE Nigeria Annual International Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/221682-ms.

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Abstract Hydro Thermal Liquefaction (HTL) emerges as a promising method for converting wet biomass into liquid fuels. However, additional processing of the resulting HTL biocrude is imperative. Elevated levels of oxygen and nitrogen in HTL-produced biocrude necessitate deoxygenation and denitrogenation before it can be effectively used as a transport fuel. Managing the by-product aqueous stream is crucial for the success of an algal biorefinery employing HTL. Consequently, maximizing HTL efficiency and optimizing the utilization of biocrude and co-products, especially aqueous by-products, are current research priorities in biorefinery studies. To boost HTL efficiency, the focus is on using only carbon and hydrogen for hydrocarbon liquid fuels, as the presence of oxygen and nitrogen is undesirable for oil applications. Oxygen lacks inherent heating value, and nitrogen, if combusted, contributes to environmental pollution. Hence, HTL involves concurrent deoxygenation and denitrogenation during biocrude formation. The primary role of HTL lies in sustainable energy and chemicals production, aligning with a commitment to environmental preservation. Biocrude, characterized by high oxygen and nitrogen contents, along with elevated molecular weight and viscosity, typically undergoes upgrading processes like solvent extraction/distillation, hydrogenation/hydrodeoxygenation, catalytic cracking, esterification, and hybrid techniques. These processes lead to the partial removal of oxygen as CO2 or H2O and the conversion of nitrogen into ammonium. The study explores potential routes for the thermochemical conversion of microalgae, distinguishing between dry processes (pyrolysis and gasification) and wet processes (near-critical water hydrothermal liquefaction and hydrothermal gasification). The work identifies key engineering advantages and challenges, focusing on biofuel production for transportation. The future perspectives for each route are presented.
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Rapporti di organizzazioni sul tema "CO/CO2 hydrogenation"

1

Author, Not Given. Hydrogenation of Clean Carbon Monoxide (CO) and Carbon Dioxide (CO2) Gas Streams to Higher Molecular Weight Alcohols. Office of Scientific and Technical Information (OSTI), febbraio 2012. http://dx.doi.org/10.2172/1035373.

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