Indexed on: 28 Oct '16Published on: 27 Oct '16Published in: Chinese Journal of Catalysis
Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reaction. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt% Au via a deposition-precipitation method. The textural properties of Zn2SnO4 support have been tuned by varying the molar ratio between base (N2H4·H2O) and metal ion (Zn2+) to be 4/1, 8/1 and 16/1. The catalytic tests for CO oxidation reaction revealed that the reactivity on Au-Zn2SnO4 with N2H4·H2O/Zn2+ = 8/1 was the highest, while the reactivity on Au-Zn2SnO4 with N2H4·H2O/Zn2+ = 16/1 was almost identical to that of the pure support. Both fresh and used catalysts have been characterized by multiple techniques including nitrogen adsorption-desorption, X-ray diffraction, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray adsorption fine structure, and temperature-programmed reduction by hydrogen. These demonstrated that the textural properties, especially pore volume and pore size distribution, of Zn2SnO4 play crucial roles in the averaged size of gold nanoparticles, and thus determine the catalytic activity of Au-Zn2SnO4 for CO oxidation.