A Comparative Study of Supported and Bulk Cu–Mn–Ce Composite Oxide Catalysts for Low-Temperature CO Oxidation

A series of supported and bulk Cu–Mn–Ce ternary oxide catalysts was synthesized by wet-impregnation (IM), deposition–precipitation (DP), traditional co-precipitation (CP), co-precipitation with cetyltrimethyl ammonium bromide (CC), and sol–gel (SG) methods. The supported catalysts (CuMn/Ce-IM, CuMn/Ce-DP) exhibited significantly higher activity for CO oxidation than the bulk catalysts (CuMnCe-CP, CuMnCe-CC and CuMnCe-SG). The improved performance could be attributed to the presence of more isolated CuO and MnO x entities on the surface of supported catalysts, which contributed to the efficient utilization of both lattice oxygen from CeO 2 and spillover oxygen from surface MnO x . For bulk catalysts, major Cu–Mn species were doped to form \({\text{C}}{{\text{u}}_{\text{x}}}{\text{M}}{{\text{n}}_{\text{y}}}{\text{C}}{{\text{e}}_{1 - {\text{x}} - {\text{y}}}}{{\text{O}}_{2 - {\text{z}}}}\) solid solutions and a part of them were coated by ceria mechanically. Lowest 50% CO conversion temperature were achieved at 76.9 °C for CuMn/Ce-IM catalyst. Low-temperature CO oxidation activities of all catalysts were in the sequence of CuMn/Ce-IM > CuMn/Ce-DP > CuMnCe-SG > CuMnCe-CC > CuMnCe-CP. Graphical Abstract