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.