biostudies-literatureLopez-Rodriguez SConsejo Nacional de Investigaciones Cient??ficas y T??cnicasMinisterio de Ciencia e Innovaci??nScience Foundation IrelandH2020 Marie Sk??odowska-Curie ActionsMinisterio de Econom??a y CompetitividadGeneralitat Valenciana25533-25544https://www.ebi.ac.uk/biostudies/studies/S-EPMC8631708biostudies-literatureUnknown125(46)This study addresses the yet unresolved CO₂ methanation mechanism on a Ru/CeO₂ catalyst by means of near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) complemented with periodic density functional theory (DFT) calculations. NAP-XPS results show that the switch from H₂ to CO₂ + H₂ mixture oxidizes both the Ru and CeO₂ phases at low temperatures, which is explained by the CO₂ adsorption modes assessed by means of DFT on each representative surface. CO₂ adsorption on Ru is dissociative and moderately endergonic, leading to polybonded Ru-carbonyl groups whose hydrogenation is the rate-determining step in the overall process. Unlike on Ru metal, CO₂ can be strongly adsorbed as carbonates on ceria surface oxygen sites or on the reduced ceria at oxygen vacancies as carboxylates (CO₂ ^-δ), resulting in the reoxidation of ceria. Carboxylates can then evolve as CO, which is released either via direct splitting at relatively low temperatures or through stable formate species at higher temperatures. DRIFTS confirm the great stability of formates, whose depletion relates with CO₂ conversion in the reaction cell, while carbonates remain on the surface up to higher temperatures. CO generation on ceria serves as an additional reservoir of Ru-carbonyls, cooperating to the overall CO₂ methanation process. Altogether, this study highlights the noninnocent role of the ceria support in the performance of Ru/CeO₂ toward CO₂ methanation.The journal of physical chemistry. C, Nanomaterials and interfacesElucidating the Role of the Metal Catalyst and Oxide Support in the Ru/CeO₂-Catalyzed CO₂ Methanation Mechanism.PMC8631708PID2019-105960RB-C22FJCI-2015-2376912/RC/2278_P2RTI2018-093996-B-32713567PROMETEO/2018/076CTQ2015-67597-C2-2-RDavo-Quinonero AGarcia-Melchor MEscudero CBailon-Garcia ELozano-Castello DHerrera FCBueno-Lopez ALopez-Rodriguez SPellegrin EfalseElucidating the Role of the Metal Catalyst and Oxide Support in the Ru/CeO₂-Catalyzed CO₂ Methanation Mechanism.This study addresses the yet unresolved CO₂ methanation mechanism on a Ru/CeO₂ catalyst by means of near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) complemented with periodic density functional theory (DFT) calculations. NAP-XPS results show that the switch from H₂ to CO₂ + H₂ mixture oxidizes both the Ru and CeO₂ phases at low temperatures, which is explained by the CO₂ adsorption modes assessed by means of DFT on each representative surface. CO₂ adsorption on Ru is dissociative and moderately endergonic, leading to polybonded Ru-carbonyl groups whose hydrogenation is the rate-determining step in the overall process. Unlike on Ru metal, CO₂ can be strongly adsorbed as carbonates on ceria surface oxygen sites or on the reduced ceria at oxygen vacancies as carboxylates (CO₂ ^-δ), resulting in the reoxidation of ceria. Carboxylates can then evolve as CO, which is released either via direct splitting at relatively low temperatures or through stable formate species at higher temperatures. DRIFTS confirm the great stability of formates, whose depletion relates with CO₂ conversion in the reaction cell, while carbonates remain on the surface up to higher temperatures. CO generation on ceria serves as an additional reservoir of Ru-carbonyls, cooperating to the overall CO₂ methanation process. Altogether, this study highlights the noninnocent role of the ceria support in the performance of Ru/CeO₂ toward CO₂ methanation.2021-01-01T00:00:00Z2021 Nov2024-11-09T13:10:30.603Z2022-02-11T13:47:11.579ZS-EPMC86317083486844510.1021/acs.jpcc.1c07537