Au Nanoparticles Supported on Iron-Based Oxides for Soot Oxidation: Physicochemical Properties Before and after the Reaction

The catalytic performance of Au nanoparticles (NPs) supported on different transition-metal oxides for soot oxidation was studied in this paper. The changes in the morphology, phase structure, and physicochemical properties of Au-supported iron-based oxides before and after the reaction with soot particles were observed by high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programed reduction. It was found that the catalytic activity of Fe3O4, Fe2O3, Co3O4, and NiO for soot oxidation was significantly improved after loading Au NPs. Especially, under the action of Au/Fe2O3 and Au/Fe3O4, the oxidation of soot was close to 20% below 420 °C, and their T 10 values were 73 and 50 °C, respectively. When Au/Fe2O3 and Au/Fe3O4 reacted with soot, the size of the catalysts increased, and the active oxygen and Fe 2p components decreased. Au promoted the reduction of iron ions to a lower temperature, which was beneficial to improving the oxidation performance of iron-based oxides.