Chromium Addition to Alumina-Supported Platinum Catalysts and Effect on Catalytic Activity in Methane Combustion

Abstract

We investigated the addition of chromium to alumina-supported Pt catalysts and its effect on catalytic activity in methane combustion. The Pt and Cr binary alumina-supported catalysts exhibited much higher activity than those without Cr. Alumina-supported Cr catalysts contain two chromium species, Cr³⁺ and Cr⁶⁺. From XPS analysis, it was found that more Cr⁶⁺ species existed in the binary catalysts than in the single alumina-supported Cr catalysts. Pt species in the binary catalysts may promote Cr oxidation. Since Cr⁶⁺ species are known to be more active than Cr³⁺ species in oxidation reactions, the increase in Cr⁶⁺ in the binary catalysts may contribute to their higher activity compared with the Pt/Al₂O₃ catalyst.