Manipulating Atomic Structures at the Au/TiO₂ Interface for O₂
Activation

The metal/oxide interface has been extensively studied due to its importance for heterogeneous catalysis. However,<br/>the exact role of interfacial atomic structures in governing catalytic processes still remains elusive. Herein, we demonstrate how the<br/>manipulation of atomic structures at the Au/TiO2 interface significantly alters the interfacial electron distribution and prompts O2<br/>activation. It is discovered that at the defect-free Au/TiO2 interface electrons transfer from Ti3+ species into Au nanoparticles (NPs)<br/>and further migrate into adsorbed perimeter O2 molecules (i.e., in the form of Au-O-O-Ti), facilitating O2 activation and leading<br/>to a ca. 34 times higher CO oxidation activity than that on the oxygen vacancy (Vo)-rich Au/TiO2 interface, at which electrons from<br/>Ti3+ species are trapped by interfacial Vo on TiO2 and hardly interact with perimeter O2 molecules. We further reveal that the<br/>calcination releases those trapped electrons from interfacial Vo to facilitate O2 activation. Collectively, our results establish an atomiclevel description of the underlying mechanism regulating metal/oxide interfaces for the optimization of heterogeneous catalysis