Methanol adsorption and dissociation on LaMnO3 and Sr doped LaMnO3 (001) surfaces

摘要

Using density functional theory, we investigate methanol adsorption and dissociation on the MnO2- and LaO-terminated LaMnO3 (001) surface as a function of Sr dopant enrichment in and near the surface. In response to bulk cleavage, we find electron depletion of the negatively charged MnO2 surface layer that is enhanced by Sr doping in the subsurface. In contrast, we observe electron accumulation in the positively charged LaO surface layer that is reduced by Sr doping in the surface layer. Methanol adsorbs dissociatively on the LaO termination of the LaMnO3 (001) surface. Methanol adsorption on the LaO termination is strongly preferred over adsorption on the MnO2 termination. While moderate doping has a small influence on methanol adsorption and dissociation, when 100% of La is replaced by Sr in the surface or subsurface, the adsorption preference of methanol is reversed. If the surface is highly dopant enriched, methanol favours dissociative adsorption on the MnO2-terminated surface. (C) 2017 Elsevier B.V. All rights reserved.