Manipulating Atomic Structures at the Au/TiO_2 Interface for O_2 Activation

摘要

The metal/oxide interface has been extensively studied due to its importance for heterogeneous catalysis. However, the exact role of interfacial atomic structures in governing catalytic processes still remains elusive. Herein, we demonstrate how the manipulation of atomic structures at the Au/TiO_2 interface significantly alters the interfacial electron distribution and prompts O_2 activation. It is discovered that at the defect-free Au/TiO_2 interface electrons transfer from Ti3+ species into Au nanoparticles (NPs) and further migrate into adsorbed perimeter O_2 molecules (i.e., in the form of Au-O-O-Ti), facilitating O_2 activation and leading to a ca. 34 times higher CO oxidation activity than that on the oxygen vacancy (V_o)-rich Au/TiO_2 interface, at which electrons from Ti~(3+) species are trapped by interfacial V_o on TiO_2 and hardly interact with perimeter O_2 molecules. We further reveal that the calcination releases those trapped electrons from interfacial V_o to facilitate O_2 activation. Collectively, our results establish an atomic-level description of the underlying mechanism regulating metal/oxide interfaces for the optimization of heterogeneous catalysis.