A series of nanosized gold supported on CeO 2 , MnO 2 , and MnO 2 -CeO 2 composite oxides have been prepared by a deposition-precipitation (DP) method and the effects of Mn/Ce atomic ratio on Au/MnO 2 -CeO 2 catalysts and calcination temperature after loading gold for preferential oxidation of CO (PROX) in H 2 stream have been investigated using a fixed-bed continuous-flow reactor at various temperatures. The catalysts were characterized by XRD, nitrogen sorption, TEM, and XPS. XRD analysis confirms the phase purity of CeO 2 and MnO 2 phases and the fine dispersion of Au on Au/MnO 2 -CeO 2 catalysts. XPS analysis shows the formation of MnO 2 -CeO 2 solid phase with manganese loading on ceria support accompanied by an increase in Ce 4+ surface concentration. ICP-AES demonstrates the increase in gold loading with manganese addition by DP method. A synergistic catalytic effect on conversion and selectivity was observed in the case of Au/MnO 2 -CeO 2 catalysts, due to the coexistence of metallic and nonmetallic gold species within nano gold particle and the minor presence of Ce 3+ species.

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