Pd/Co3O4 Nanoparticles Inlaid in Alkaline Al2O3 Nanosheets as an Efficient Catalyst for Catalytic Oxidation of Methane

We report an efficient catalyst composed of ternary components prepared by inlaying Pd/Co3O4 nanoparticles in alkaline Al2O3 nanosheets for catalytic oxidation of methane. Pd/Co3O4 inlaid in alkaline Al2O3 exhibited a higher ability to break the C-H bond of methane than Pd/Co3O4 supported on SiO2, ZrO2, CeO2, and acidic or neutral Al2O3. Our results show more oxygen vacancies and higher amounts of surface adsorbed oxygen on the surface of Pd/Co3O4/alkaline Al2O3 than on other catalysts, which is responsible for methane activation and conversion. Further, the Pd/Co3O4/alkaline Al2O3 catalyst can almost restore to its initial value in the absence of water when 5% (volume fraction) vapor water was cut off, although a decrease in activity occurred when water vapor was introduced to the reaction system. Even under a condition similar to the exhaust of a lean-burn natural gas engine, the catalytic performance of the Pd/Co3O4/alkaline Al2O3 catalyst is excellent, that is, methane could be completely converted when the sample temperature in the reaction atmosphere was ramped to 400°C.