Highly Active and Stable Pd−GaOx/Al2O3 Catalysts Derived from Intermetallic Pd5Ga3 Nanocrystals for Methane Combustion.

Catalytic combustion of methane is widely used in industrial and transportation activities. The commonly used Pd‐based catalysts, however, are easily deactivated under hydrothermal conditions. In this work, we adopted a novel strategy to prepare a GaOx‐doped Pd/Al2O3 catalyst via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on γ‐Al2O3. We observed a synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase, resulting in a highly active and exceptionally stable catalyst that could markedly suppress the sintering of noble metals under harsh conditions (hydrothermal treatment at 750 °C). Moreover, the presence of a large amount of surface oxygen vacancies and the surface Pd−O−Ga phase could promote methane combustion over the catalysts. It is believed that such a novel dual‐metal catalyst is promising in practical applications for methane combustion. Effective synergy: The Pd−GaOx/Al2O3 catalysts are prepared via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on Al2O3. A synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase is observed, resulting in a highly active and exceptionally stable catalyst that can markedly suppress the sintering of noble metals under harsh conditions. Surface oxygen vacancies and the surface Pd−O−Ga phase are the catalytically active sites. [ABSTRACT FROM AUTHOR]