Effects of Support Preparation Methods on Structural and Catalytic Properties of Au/MnO_x-CeO₂

The preparation method for the heterogeneous catalysts makes a crucial role in catalytic activities. Here, we applied the co-precipitation, sol-gel, and impregnation method to prepare a series of MnOx-CeO2 supports with different Ce: Mn atom ratios at 9:1 and 8:2. After loaded with 1 wt% of Au, the obtained Au/MnOx-CeO2 were evaluated for low-temperature CO oxidation and water-gas shift reaction. Nitrogen adsorption, X-ray diffraction (XRD), Raman spectroscopy, temperature-programmed reduction (TPR), and Transmission Electron Microscopy Energy Dispersive Spectroscopy (TEM-EDS) showed that co-precipitation gave the formation of homogeneous distribution of active sites of MnOx-CeO2 oxides and the doping of Mn led to the formation of fluorite-type solid. The Au/C8M2-C catalyst prepared by co-precipitation performed best in low-temperature CO oxidation and water-gas shift reaction, which may be due to the homogeneous distribution of active sites. The doped Mn also demonstrated a great improvement over the low-temperature CO oxidation, implying the strengthened redox-oxidation capabilities.{GRAPHICAL ABSTRACT}