文献类型：期刊文献

英文题名：Surface phase diagrams of La-based perovskites towards the O-rich limit from first principles

作者：Li, Yang[1];Yang, Jie[1];Zhu, Yi-An[1];Sui, Zhi-Jun[1];Zhou, Xing-Gui[1];Chen, De[2];Yuan, Wei-Kang[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, United Chem React Engn Res Inst UNILAB, Shanghai 200237, Peoples R China;[2]Norwegian Univ Sci & Technol, Dept Chem Engn, N-7491 Trondheim, Norway

年份：2019

卷号：21

期号：24

起止页码：12859

外文期刊名：PHYSICAL CHEMISTRY CHEMICAL PHYSICS

收录：;EI(收录号：20201708549080);WOS:【SCI-EXPANDED(收录号:WOS:000472214000010)】；

基金：This work is supported by the Natural Science Foundation of China (21473053, 91645122, and U1663221), the National Key Research and Development Program of China (2018YFB0604700), and the Fundamental Research Funds for the Central Universities (222201718003). The computational time provided by the Notur project is highly acknowledged. Y. L. would also like to thank Prof. Hong-Lai Liu at ECUST for valuable discussions.

语种：英文

外文关键词：Oxygen vacancies - Chemical potential - Ionization of gases - Perovskite - Positive ions - Phase diagrams - Cobalt compounds - Gas adsorption - Transition metals - Transition metal oxides - Copper compounds - Oxygen - Lanthanum compounds - Binary alloys

摘要：The exposed termination of transition-metal oxide surfaces plays a major role in determining the catalyst performance in redox reactions. In this contribution, the surface phase diagrams of LaMO3(001) (M = Sc-Fe) and LaMO3(110) (M = Co-Cu) are constructed by using the DFT+U method. The stabilities of six terminations derived from the stoichiometric MO2 and LaO surfaces are determined over a wide range of temperatures and oxygen partial pressures. The surface phase diagrams are calculated towards the O-rich limit in which the chemical potential of oxygen anions of perovskites equals that of gas-phase oxygen while the chemical potential of M cations is limited by thermodynamic boundary conditions. It is found that the surface phase diagrams are closely related to the reducibility of M cations, which is reflected in the oxygen adsorption energy and oxygen vacancy formation energy on the MO2- and LaO-terminated surfaces and can be measured by the third ionization energies of the M2+ cations. According to the surface phase diagrams, the most stable surface termination is predicted to be of MO2 type for LaMO3 (M = Sc-Fe) and LaO type for LaMO3 (M = Co-Cu) under solid oxide fuel cell operating conditions. Because the M cations become more readily reduced on going from left to right across the period, LaCoO3 may form an oxygen-deficient crystal structure at high temperatures and LaNiO3 and LaCuO3 would be decomposed into oxides containing the transition metals in a lower oxidation state.