Three-dimensionally ordered macroporous Au/CeO2–Co3O4 catalysts with mesoporous walls for enhanced CO preferential oxidation in H2-rich gases

Abstract

Three-dimensionally ordered macroporous (3DOM) Au/CeO2–Co3O4 catalysts with well-defined macroporous skeletons and mesoporous walls were created via a precursor thermal decomposition-assisted colloidal crystal templating method, and their catalytic performance for CO preferential oxidation in H2-rich gases was systematically investigated. The results showed that the 3DOM Au/CeO2–Co3O4 catalysts possessed well-defined 3DOM skeletons composed of well-crystallized CeO2 and Co3O4 nanoparticles and mesoporous walls with nanopores ∼3–4nm. Their catalytic performance was closely correlated to their compositions, phase structures, porous architectures, surface elemental compositions, and valence states. In comparison with the Au supported CeO2 or Ce3O4 catalysts previously reported, the 3DOM Au/CeO2–Co3O4 catalysts showed superior catalytic conversion, selectivity, and stability—in particular, longer-term stability—for CO preferential oxidation in H2-rich gases, making them potentially applicable in polymer electrolyte membrane fuel cells.