Crystal-Plane Effects on the Catalytic Properties of Au/TiO2

In this work, Au nanoparticles are loaded on TiO2 nanocrystals with different crystal planes exposed ({100}, {101}, and {001} planes) to investigate the crystal-plane effect on the catalytic properties of Au/TiO2 catalyst. Kinetic studies of CO oxidation show that the catalytic activities of three as-prepared Au/TiO2 samples follow this order: Au/TiO2-{100} > Au/TiO2-{101} > Au/TiO2-{001}. Furthermore, different mechanisms exist at low temperatures (<320 K) and high temperatures (>320 K). With the help of ex-situ XPS and in situ DRIFTS, the interactions between substrate molecules and different Au/TiO2 interfaces are investigated. We find that the activation of O-2 and the formation and desorption of carbonates are greatly dependent on the crystal planes of the TiO2 support. Furthermore, we use CO oxidation as a probe reaction to study the relationships between surface structures and catalytic properties in Au/TiO2. The catalytic behaviors of three Au/TiO2 catalysts are well correlated with the spectroscopic results. On the basis of this work, we believe that tuning the crystal plane of TiO2 support will be an effective strategy to control the catalytic properties of Au/TiO2.