Tuning Selectivity of CO2 Hydrogenation via Support Composition Modification Adjusted the Activity Reduction of H Species over Ce1–xPrxO2−δ-Supported Metal (Ru, Rh) Nanoclusters
{"title":"Tuning Selectivity of CO2 Hydrogenation via Support Composition Modification Adjusted the Activity Reduction of H Species over Ce1–xPrxO2−δ-Supported Metal (Ru, Rh) Nanoclusters","authors":"De-Jiu Wang, Xiao-Chen Sun, Hai-Jing Yin, Hao Dong, HaiChao Liu* and Ya-Wen Zhang*, ","doi":"10.1021/acscatal.4c01201","DOIUrl":null,"url":null,"abstract":"<p >Selectivity control of supported metal catalysts, which are most widely utilized in the field of heterogeneous catalysis, is of great scientific significance to obtaining the desired chemical product in a multipath reaction but has remained a grand challenging issue. In this work, we demonstrate that the selectivity of CO<sub>2</sub> hydrogenation from CH<sub>4</sub> to CO can be tuned by a robust and unique support doping strategy by changing the reduction activity of H species over M/Ce<sub>1–<i>x</i></sub>Pr<sub><i>x</i></sub>O<sub>2−δ</sub> (M = Ru, Rh) in which metal (M) nanoclusters showed the same existence form on differently doped ceria nanorod supports. The CH<sub>4</sub> selectivity of the catalyst decreased with an increase in the Pr content in the support. The selectivity of CH<sub>4</sub> on Ru/CeO<sub>2</sub> was higher than 90%, while on Ru/Ce<sub>0.2</sub>Pr<sub>0.8</sub>O<sub>2−δ</sub>, the selectivity of CO reached 80%. A variety of techniques, including steady-state isotope transient kinetic analysis (SSITKA) type in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)–mass spectrum (MS), temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR), had been applied in this work to analyze the structure–activity relationship between the doping of Pr and the selectivity of the CO<sub>2</sub> hydrogenation reaction. Ru sites were not directly involved in the hydrogenation of carbon-containing intermediate species (including bicarbonate and formate) during the CO<sub>2</sub> hydrogenation reaction. The active H species on the support sites, which are incorporated in RE<sup>3+</sup>–OH, directly contacted and reacted with the carbon-containing intermediate species. The introduction of Pr in the support weakened the reducing ability of the support, thus decreasing the reducing ability of H species on the surface of the catalyst, which further hindered the conversion of formate into CH<sub>4</sub>, resulting in the declined CH<sub>4</sub> selectivity. Our study clearly revealed the important role of support in the CO<sub>2</sub> hydrogenation reaction and proposed a strategy to modulate the reaction selectivity via support doping. By changing the redox performance of the support, the activity of H species on the support can be adjusted. Thus, the conversion of important reaction intermediates (such as formate) can be affected, so as to achieve precise regulation of the reaction products. We have provided a broader perspective for the selective catalyst design of heterogeneous catalysis and the reaction mechanism study of supported metal catalysts.</p>","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acscatal.4c01201","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Selectivity control of supported metal catalysts, which are most widely utilized in the field of heterogeneous catalysis, is of great scientific significance to obtaining the desired chemical product in a multipath reaction but has remained a grand challenging issue. In this work, we demonstrate that the selectivity of CO2 hydrogenation from CH4 to CO can be tuned by a robust and unique support doping strategy by changing the reduction activity of H species over M/Ce1–xPrxO2−δ (M = Ru, Rh) in which metal (M) nanoclusters showed the same existence form on differently doped ceria nanorod supports. The CH4 selectivity of the catalyst decreased with an increase in the Pr content in the support. The selectivity of CH4 on Ru/CeO2 was higher than 90%, while on Ru/Ce0.2Pr0.8O2−δ, the selectivity of CO reached 80%. A variety of techniques, including steady-state isotope transient kinetic analysis (SSITKA) type in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)–mass spectrum (MS), temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR), had been applied in this work to analyze the structure–activity relationship between the doping of Pr and the selectivity of the CO2 hydrogenation reaction. Ru sites were not directly involved in the hydrogenation of carbon-containing intermediate species (including bicarbonate and formate) during the CO2 hydrogenation reaction. The active H species on the support sites, which are incorporated in RE3+–OH, directly contacted and reacted with the carbon-containing intermediate species. The introduction of Pr in the support weakened the reducing ability of the support, thus decreasing the reducing ability of H species on the surface of the catalyst, which further hindered the conversion of formate into CH4, resulting in the declined CH4 selectivity. Our study clearly revealed the important role of support in the CO2 hydrogenation reaction and proposed a strategy to modulate the reaction selectivity via support doping. By changing the redox performance of the support, the activity of H species on the support can be adjusted. Thus, the conversion of important reaction intermediates (such as formate) can be affected, so as to achieve precise regulation of the reaction products. We have provided a broader perspective for the selective catalyst design of heterogeneous catalysis and the reaction mechanism study of supported metal catalysts.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.