Detection of a real heterogeneous catalyst with an inactive oxygen-covered surface: Au/Li4Ti5O12

Abstract

In the investigation of the catalytic mechanism, O-covered transition-metal oxide surfaces with concealed transition-metal cations are occasionally employed as model catalyst support structures. These are the most extreme models for investigating the importance of O species on the support surface. There are few cases in which a catalytic metal is supported on O-covered surfaces, and its catalytic activity is confirmed. In this study, we confirmed that the most exposed surface of Li4Ti5O12 is the O-covered (Ti-sublayer) (111) surface, and we prepared and evaluated a real catalyst using Li4Ti5O12 as the support. Au nanoparticles were used as the catalytic metal, and the interface orientation was determined to be Au(111)//Li4Ti4O12(111). Furthermore, the interface comprising the inactive O-covered (Ti-sublayer) surfaces of transition-metal oxides exhibited catalytic activity. These are important for examining the catalytic mechanism using the surface O species of the support by theoretical calculations, thereby bridging the gap between theory and experiments.