低碳化学与化工2025，Vol.50Issue(3)：12-22,11.DOI:10.12434/j.issn.2097-2547.20240209
Li掺杂La2O3催化剂上甲烷氧化偶联反应中氧物种迁移及类型对CH4解离影响的DFT研究
DFT study on effects of oxygen species migration and its type on CH4 dissociation in oxidative coupling of methane reaction on Li-doped La2O3 catalysts
摘要
Abstract
La2O3 catalysts have been widely used in the oxidative coupling of methane(OCM)reaction,however,identifying the types of key oxygen species and its influence on methane dissociation activity is still a challenge.The oxygen migration,the types of oxygen species formed during oxygen migration and the influence of oxygen species types on methane dissociation activity over Li-doped La2O3 catalysts were investigated by density functional theory(DFT)calculation.The results show that for the Li/Ov-La2O3 catalysts,O2 forms the surface superoxide species O2-(1st)at the oxygen vacancies on the surface of the catalysts,and then one O of the surface superoxide species O2-(1st)migrates to the subsurface layer to form the subsurface peroxide species O22-(2nd),namely the Li/Ov-La2O3-O22-(2nd)catalysts.For the Li/La2O3 catalysts,O2 dissociates and combines with the lattice oxygen on the surface of the catalysts to form two surface superoxide species O2-(1st),and then one O of the surface superoxide species O2-migrates to the subsurface layer to form the subsurface peroxide species O22-(2nd),namely the Li/-La2O3-O2-(1st)+O22-(2nd)catalysts.Li/Ov-La2O3-O22-(2nd)and Li/La2O3-O2-(1st)+O22-(2nd)catalysts with subsurface O22-(2nd)species,which enhance CH4 dissociation ability and make CH4 spontaneous dissociation occur to form adsorbed state CH3 and H.This is mainly due to the presence of the subsurface peroxide species O22-(2nd),which makes the surface O of the catalysts at a state of electron deficiency and improves the methane dissociation ability of the catalyst.关键词
甲烷氧化偶联反应/La2O3催化剂/氧迁移/氧物种/Li掺杂Key words
oxidative coupling of methane reaction/La2O3 catalysts/oxygen migration/oxygen species/Li-doped分类
化学工程引用本文复制引用
刘思,章日光..Li掺杂La2O3催化剂上甲烷氧化偶联反应中氧物种迁移及类型对CH4解离影响的DFT研究[J].低碳化学与化工,2025,50(3):12-22,11.基金项目
国家重点研发计划(2021YFA1502804) （2021YFA1502804）
山西省杰出青年科学基金(202103021221005). （202103021221005）
