Hydrogen and methane oxidation performances of hybrid honeycomb catalyst for a tritium removal system

The oxidation properties of new type honeycomb catalysts using NA honeycomb support material were evaluated with hydrogen and methane gases in air to compare the simple catalysts with platinum or palladium to hybrid catalysts with both platinum and palladium. Hybrid catalysts impregnated platinum and palladium were made by a co-impregnation method (Pt + Pd) and a sequential impregnation method (Pt/Pd) and the total amount of noble metal was prepared to 2 g/L. The oxidation performance was conducted with specific flow of about 1.2 s−1 in the temperature range of less than 400 °C. As the results, the NA honeycomb catalysts impregnated platinum gave the highest oxidation reaction rate for hydrogen gas among various type honeycomb catalysts. However, methane oxidation performances were inferior to other honeycomb catalysts. On the other hand, only hybrid NA catalyst manufactured by the co-impregnation method exhibited the high oxidation performance of both hydrogen and methane. It was suggested that the impregnation method of two noble metals was the key technique to take a synergic effect.