Synthesis of Macro-Mesoporous Pt/alumina Catalyst to Enhance Catalytic Activity of Hydrogen Oxidation

Macro-mesoporous Pt/alumina catalysts were synthesized by the sol-gel process with the assistance of a PS colloidal crystal template to improve the catalytic activity of hydrogen oxidation. Macropores in catalysts improve hydrogen gas diffusion and enhance the accessibility of hydrogen gas to the center of the catalyst. The diffusion coefficients of hydrogen gas in macro- and mesopores were theoretically calculated. The effect of macropores on exothermic properties induced by hydrogen oxidation was investigated using various concentrations of H-2/air gas mixture. The temperature increase of macro-mesoporous Pt/alumina was dramatically higher than that of mesoporous Pt/alumina without macropores. The results clearly show that macropores effectively improve the catalytic reaction of hydrogen oxidation.