Variation of redox activity and synergistic effect for improving the preferential oxidation of CO in H2-rich gases in porous Pt/CeO2–Co3O4 catalysts

Abstract

Porous Pt/CeO₂–Co₃O₄ catalysts are fabricated via thermal decomposition of cerium nitrate hexahydrate and cobaltous acetate tetrahydrate precursors using polystyrene sphere colloidal crystals as templates followed by Pt impregnation. The obtained catalysts possess well-defined macroporous skeletons and mesoporous walls, adjustable chemical compositions, and varied surface elemental states. The macro- and meso-porous Pt/CeO₂–Co₃O₄ catalysts show superior catalytic performance to traditional powder Pt/CeO₂–Co₃O₄ catalysts for CO preferential oxidation in H₂-rich gases. The redox activity and the valence state of the macro- and meso-porous Pt/CeO₂–Co₃O₄ catalysts are largely varied depending on their chemical compositions and further cause the strong synergy between Pt, CeO₂ and Co₃O₄, which accounts for the improvement of catalytic performance. Meanwhile, the macro- and meso-porous structure in Pt/CeO₂–Co₃O₄ catalysts is conducive to the diffusion of reactants and products, thus enhancing the catalytic performance simultaneously.