Pentacoordinated Al 3+ ‐Stabilized Active Pd Structures on Al 2 O 3 ‐Coated Palladium Catalysts for Methane Combustion

Supported Pd catalysts are active in catalyzing the highly exothermic methane combustion reaction but tend to be deactivated owing to local hyperthermal environments. Herein we report an effective approach to stabilize Pd/SiO 2 catalysts with porous Al 2 O 3 overlayers coated by atomic layer deposition (ALD). 27 Al magic angle spinning NMR analysis showed that Al 2 O 3 overlayers on Pd particles coated by the ALD method are rich in pentacoordinated Al 3+ sites capable of strongly interacting with adjacent surface PdO x phases on supported Pd particles. Consequently, Al 2 O 3 ‐decorated Pd/SiO 2 catalysts exhibit active and stable PdO x and Pd–PdO x structures to efficiently catalyze methane combustion between 200 and 850 °C. These results reveal the unique structural characteristics of Al 2 O 3 overlayers on metal surfaces coated by the ALD method and provide a practical strategy to explore stable and efficient supported Pd catalysts for methane combustion.