燃料化学学报（中英文）2023，Vol.51Issue(5)：673-683,11.DOI:10.1016/S1872-5813(23)60343-3
不同价态金属掺杂对La2O3(001)表面上甲烷活化影响的研究
Effect of different valence metals doping on methane activation over La2O3(001) surface
摘要
Abstract
La2O3 as a catalyst is used for oxidative coupling of methane (OCM) reactions due to its excellent stability and high C2 selectivity, but poor activity on methane dissociation limits its wide application. Different valence metals are doped on the La2O3(001) surface to improve the methane conversion activity, and the activation of methane on metal-doped La2O3(001) surfaces has been investigated via the density functional theory (DFT) calculations. The relationship between the valence states of doped metals and the methane conversion activities shows that doping low valence metals (Li, Na, K, Mg, Ca, Sr and Ba) and equivalent metals (Al, Ga, In) can significantly improve the conversion activity of methane. Among them, the activation energy of methane on the Li-La2O3(001) surface is the lowest, which is only 13.0 kJ/mol. However, doping of high valence metals (Zr, Nb, Re and W) cannot improve the CH4 dissociation activity. Furthermore, the relationships between surface oxygen vacancy formation energies, acid-base properties and the activation energies of CH4 have also been investigated. The results show that with the increase of metal valence state, the oxygen vacancy formation energy increases, while the dissociation activity of CH4 decreases. The introduction of alkali and alkaline earth metals increases the alkalinity of La2O3(001) surface, and the alkalinity of La2O3(001) doped with the alkali metal is stronger than that with the alkaline earth metal, exhibiting higher dissociation activity of CH4. Our research may provide a guide for improving methane conversion activity on La2O3 catalysts.关键词
甲烷/La2O3催化剂/金属掺杂/活性/密度泛函理论Key words
methane/La2O3 catalyst/metal doping/activity/density functional theory分类
化学化工引用本文复制引用
张家宇,孙娜,凌丽霞,章日光,贾丽涛,李德宝,王宝俊..不同价态金属掺杂对La2O3(001)表面上甲烷活化影响的研究[J].燃料化学学报（中英文）,2023,51(5):673-683,11.基金项目
The project was supported by the National Key R&D Program of China(2021YFA1502804),Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-FR001),the Key Projects of National Natural Science Foundation of China(21736007),and the Natural Science Foundation of Shanxi Province(20210302123094). （2021YFA1502804）
