Relationship between hydrothermal temperatures and structural properties of CeO2 and enhanced catalytic activity of propene/toluene/CO oxidation by Au/CeO2 catalysts

A simple hydrothermal synthesis of CeO 2 was implemented to obtain a series of CeO 2 -supported gold (Au) catalysts, used for the total oxidation of propene/toluene/CO gas mixtures and the oxidation of CO. CeO 2 preparation started from a cerium hydrogen carbonate precursor using a range of different hydrothermal temperatures (HT) from 120 to 180°C. High-resolution transmission electron microscopy, X-ray diffraction, and H 2 -temperature-programmed reduction data indicated that CeO 2 morphology varied with the HT, and was composed of the more active (200) surface. Following Au deposition onto the CeO 2 support, this active crystal plane resulted in the most widely dispersed Au nanoparticles on the CeO 2 support. The catalytic performance of the CeO 2 -supported Au catalysts for both oxidation reactions improved as the reducibility increased to generate lattice oxygen vacancies and the number of adsorbed peroxide species on the CeO 2 support increased due to addition of Au. The Au catalyst on the CeO 2 support prepared at 120°C was the most active in both propene/toluene/CO oxidation and independent CO oxidation.