Facet-dependent activity of shape-controlled TiO2 supported Au nanoparticles for the water–gas shift reaction†
Abstract
The bifunctional role of the noble metal/oxide interface in the activation of reactants is of vital importance in heterogeneous catalysis of the water–gas shift (WGS) reaction. Herein, three types of shape-controlled TiO2 supports with main exposed facets of {001}, {100} and {101} have been synthesized to study the effect of the interface structure on the catalytic performance of supported Au nanoparticles. Au/TiO2 with TiO2 octahedra exhibits excellent low temperature catalytic activity with a turnover frequency of 0.093 s−1 at 150 °C. When the reaction temperature exceeds 250 °C, Au/TiO2 with TiO2 nanosheets shows higher activity than the other two kinds of Au/TiO2. The surface oxygen species analysis and in situ diffuse reflectance infrared Fourier transform spectroscopy results indicate that both the decomposition of carbonates and activation of water at the interface of Au/TiO2 are the keys to catalytic activities. Our results provide new insights into understanding the interface structure–property relationship of Au/TiO2 catalysts for the WGS reaction.