Development of highly selective PdZn/CeO2 and Ca-doped PdZn/CeO2 catalysts for methanol synthesis from CO2 hydrogenation

Malik, Ali Shan; Zaman, Sharif F.; Al-Zahrani, Abdulrahim A.; Daous, Muhammad A.; Driss, Hafedh; Petrov, L.

doi:10.1016/j.apcata.2018.04.036

Cited by 119 publications

(75 citation statements)

References 82 publications

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“…This is indeed the case of CeO x /Cu(111), whose superior activity for methanol production is attributed to the abundance of Ce 3+ sites that can stabilize CO2δ- intermediates. The synergistic effect between the metal and CeO 2 has been reported also on conventional systems in which the metal is deposited onto the ceria surface, and again the enhanced activity for CO 2 hydrogenation has been attributed to the increased reduction of ceria promoted by metal-support interaction and the subsequent formation of oxygen vacancies (Tsubaki and Fujimoto, 2003; Choi et al, 2017; Vourros et al, 2017; Malik et al, 2018). The relevance of this interaction is nicely demonstrated by Vourros et al, who compares the activity of gold nanoparticles supported on different oxides.…”

Section: Co2 Hydrogenation To Value Added Chemicals Other Than Methanementioning

confidence: 74%

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

2019

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Reducing greenhouse emissions is of vital importance to tackle the climate changes and to decrease the carbon footprint of modern societies. Today there are several technologies that can be applied for this goal and especially there is a growing interest in all the processes dedicated to manage CO 2 emissions. CO 2 can be captured, stored or reused as carbon source to produce chemicals and fuels through catalytic technologies. This study reviews the use of ceria based catalysts in some important CO 2 valorization processes such as the methanation reaction and methane dry-reforming. We analyzed the state of the art with the aim of highlighting the distinctive role of ceria in these reactions. The presence of cerium based oxides generally allows to obtain a strong metal-support interaction with beneficial effects on the dispersion of active metal phases, on the selectivity and durability of the catalysts. Moreover, it introduces different functionalities such as redox and acid-base centers offering versatility of approaches in designing and engineering more powerful formulations for the catalytic valorization of CO 2 to fuels.

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Section: Co2 Hydrogenation To Value Added Chemicals Other Than Methanementioning

confidence: 74%

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

2019

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“…At the same time, more intensive absorption bands in the range 3500-3700 cm −1 can be observed, which could be caused by both the corresponding OH valence vibrations or the overtone vibrations of the CO-bonds [67]. Based on known vibrational frequencies for different molecular components, a possible methanol formation was observed [68].…”

Section: In Situ Diffuse Reflection Fourier Transform Infrared Spectrmentioning

confidence: 99%

Synthesis, Modification, and Characterization of CuO/ZnO/ZrO2 Mixed Metal Oxide Catalysts for CO2/H2 Conversion

et al. 2019

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CuO/ZnO/ZrO2 catalyst systems were synthesized in different ways and comprehensively characterized in order to study synthesis-to-property relations. A series of catalyst samples was prepared by coprecipitation, one-pot synthesis, and wet impregnation. The coprecipitation of multicomponent precipitates is usually a preliminary stage for preparation of mixed oxide catalysts. Cetyltrimethylammonium bromide (CTAB) was used in the surfactant-supported coprecipitation to improve the structural or textural characteristics of the catalytic samples. In the one-pot synthesis, all necessary components are simultaneously converted by evaporation from solutions into solids. During the wet impregnation, zirconium hydroxide is loaded with metal salts. After thermal treatment, all samples formed pure metal oxide forms, which was confirmed by XRD. The specific surface area of the investigated samples and their porous texture were determined by nitrogen adsorption. The reducibility of metal oxides and the kind of CuO phase was characterized by temperature-programmed reduction (TPR), and the surface acid properties by temperature-programmed ammonia desorption (TPAD). The CuO/ZnO/ZrO2 sample with the highest amount of strong acid sites is characterized by the formation of large CuO particles combined with the worst reducibility so that potentially catalytic active Cu/CuO pairs can be formed. One catalyst system was further characterized by in situ diffuse reflection Fourier transform infrared spectroscopy (DRIFTS) to identify surface intermediate species, which may occur during the conversion of CO2/H2 to methanol.

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“…During the CO 2 hydrogenation on a PdZn/TiO 2 catalyst, methanol is formed over PdZn surfaces, [15,16,23] CO can be produced over metallic Pd [13,15,24] or PdZn, [25] however, little is known about the active sites for CH 4 formation on PdZn alloys. In this work, it is proposed that over PdZn/TiO 2 catalysts CH 4 is not formed through the methanation of CO 2 , but instead as a by-product of CH 3 OH decomposition at TiO 2 sites.…”

Section: Introductionmentioning

confidence: 99%

CO₂ Hydrogenation to CH₃OH over PdZn Catalysts, with Reduced CH₄ Production

et al. 2020

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Metallic Pd, under CO 2 hydrogenation conditions (> 175°C, 20 bar in this work), promotes CO formation via the reverse water gas shift (RWGS) reaction. Pd-based catalysts can show high selectivity to methanol when alloyed with Zn, and PdZn alloy catalysts are commonly reported as a stable alternative to Cu-based catalysts for the CO 2 hydrogenation to methanol. The production of CH 4 is sometimes reported as a minor by-product, but nevertheless this can be a major detriment for an industrial process, because methane builds up in the recycle loop, and hence would have to be purged periodically. Thus, it is extremely important to reduce methane production for future green methanol synthesis processes. In this work we have investigated TiO 2 as a support for such catalysts, with Pd, or PdZn deposited by chemical vapour impregnation (CVI). Although titania-supported PdZn materials show excellent performance, with high selectivity to CH 3 OH + CO, they suffer from methane formation (> 0.01 %). However, when ZnTiO 3 is used instead as a support medium for the PdZn alloy, methane production is greatly suppressed. The site for methane production appears to be the TiO 2 , which reduces methanol to methane at anion vacancy sites.

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Development of highly selective PdZn/CeO2 and Ca-doped PdZn/CeO2 catalysts for methanol synthesis from CO2 hydrogenation

Cited by 119 publications

References 82 publications

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

Synthesis, Modification, and Characterization of CuO/ZnO/ZrO2 Mixed Metal Oxide Catalysts for CO2/H2 Conversion

CO₂ Hydrogenation to CH₃OH over PdZn Catalysts, with Reduced CH₄ Production

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Development of highly selective PdZn/CeO2 and Ca-doped PdZn/CeO2 catalysts for methanol synthesis from CO2 hydrogenation

Cited by 119 publications

References 82 publications

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

Synthesis, Modification, and Characterization of CuO/ZnO/ZrO2 Mixed Metal Oxide Catalysts for CO2/H2 Conversion

CO2 Hydrogenation to CH3OH over PdZn Catalysts, with Reduced CH4 Production

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CO₂ Hydrogenation to CH₃OH over PdZn Catalysts, with Reduced CH₄ Production