Crystal Plane Effect of ZnO on the Catalytic Activity of Gold Nanoparticles for the Acetylene Hydrogenation Reaction

The interface between gold and the support plays a vital role in various catalytic reactions. To investigate its effect on the selective hydrogenation of acetylene over gold catalysts, we deliberately created two different Au-ZnO interfaces by supporting the thiolated Au-25 precursor on two ZnO supports with different shapes: one was platelike with polar planes, and the other was needlelike exhibiting nonpolar planes. The particle sizes of gold were controlled with similar average sizes (similar to 2.5 nm) on the ZnO plate and ZnO needle. The catalytic performance of the Au/ZnO needle for the acetylene hydrogenation reaction was much better than that of the Au/ZnO plate. The characterization results of the in situ diffuse reflectance infrared Fourier transform spectroscopy showed that the intensity of the adsorption band of CO over the metallic gold was much stronger over the Au/ZnO needle than that on the Au/ZnO plate. Therefore, it could be concluded that the ability of the nonpolar plane in the needlelike ZnO to stabilize metallic gold might be responsible for the superior catalytic performance of the Au/ZnO needle. This work can not only give deep insight into the crystal plane effect on the Au/ZnO catalyst but also provide a good way to create different metal support interfaces in other catalytic systems by depositing the same metal particles on the supports with different crystal planes.