{"title":"Band gap effect of TiO2 on supported Ru single-atom catalysts for CO2 methanation by DFT calculations","authors":"","doi":"10.1016/j.mcat.2024.114665","DOIUrl":null,"url":null,"abstract":"<div><div>The influence of TiO<sub>2</sub> band gap on structure and reactivity of the supported single ruthenium (Ru<sub>1</sub>) atom was studied by density functional theory calculations, utilizing Ru<sub>1</sub>/2L-TiO<sub>2</sub> and Ru<sub>1</sub>/3L-TiO<sub>2</sub> as model catalysts for CO<sub>2</sub> methanation. The supports have band gaps of 2.39 eV and 1.48 eV, respectively. The band gap plays a significant role in electronic metal-support interactions (EMSIs) and the position of the d-band center of the Ru<sub>1</sub> on the TiO<sub>2</sub>. The Ru<sub>1</sub>/3L-TiO<sub>2</sub>, the Ru<sub>1</sub> catalyst supported on the 3L-TiO<sub>2</sub> with a narrower band gap, shows enhanced EMSIs and a d-band center that is positioned farther from Fermi level, leading to lower charge density on the Ru<sub>1</sub> and weaker adsorption of H<sub>2</sub>, CO<sub>2</sub>, and CO compared to the Ru<sub>1</sub>/2L-TiO<sub>2</sub>. CO<sub>2</sub> methanation followed CO pathway, with the hydrogenation of CO* to HCO* identified as the rate-determining step on the Ru<sub>1</sub>/nL-TiO<sub>2</sub>. The Ru<sub>1</sub> catalyst supported on TiO<sub>2</sub> with a narrower band gap is more favorable kinetically and thermodynamically for CO<sub>2</sub> methanation, despite the band gap not altering the reaction pathway. Enhanced hydrogen mobility and a pronounced promotional effect of hydrogen on CO adsorption, due to the narrower band gap support, are key factors facilitating the easier hydrogenation of CO* on the Ru<sub>1</sub>/3L-TiO<sub>2</sub>.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":null,"pages":null},"PeriodicalIF":3.9000,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Molecular Catalysis","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2468823124008472","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The influence of TiO2 band gap on structure and reactivity of the supported single ruthenium (Ru1) atom was studied by density functional theory calculations, utilizing Ru1/2L-TiO2 and Ru1/3L-TiO2 as model catalysts for CO2 methanation. The supports have band gaps of 2.39 eV and 1.48 eV, respectively. The band gap plays a significant role in electronic metal-support interactions (EMSIs) and the position of the d-band center of the Ru1 on the TiO2. The Ru1/3L-TiO2, the Ru1 catalyst supported on the 3L-TiO2 with a narrower band gap, shows enhanced EMSIs and a d-band center that is positioned farther from Fermi level, leading to lower charge density on the Ru1 and weaker adsorption of H2, CO2, and CO compared to the Ru1/2L-TiO2. CO2 methanation followed CO pathway, with the hydrogenation of CO* to HCO* identified as the rate-determining step on the Ru1/nL-TiO2. The Ru1 catalyst supported on TiO2 with a narrower band gap is more favorable kinetically and thermodynamically for CO2 methanation, despite the band gap not altering the reaction pathway. Enhanced hydrogen mobility and a pronounced promotional effect of hydrogen on CO adsorption, due to the narrower band gap support, are key factors facilitating the easier hydrogenation of CO* on the Ru1/3L-TiO2.
期刊介绍:
Molecular Catalysis publishes full papers that are original, rigorous, and scholarly contributions examining the molecular and atomic aspects of catalytic activation and reaction mechanisms. The fields covered are:
Heterogeneous catalysis including immobilized molecular catalysts
Homogeneous catalysis including organocatalysis, organometallic catalysis and biocatalysis
Photo- and electrochemistry
Theoretical aspects of catalysis analyzed by computational methods