Construction of a Pd(PdO)/Co3O4@SiO2 core–shell structure for efficient low-temperature methane combustion

Abstract

Catalytic combustion is a promising way to remove trace amounts of CH₄ to alleviate serious environmental concerns. However, the reactivity of a catalyst at low temperature is usually limited because of the difficulty to activate the C–H bond of methane. Herein, we design a Pd(PdO)/Co₃O₄@SiO₂ bimetallic oxide core–shell catalyst which shows much higher activity in the methane combustion reaction compared with Pd(PdO)/SiO₂ and Co₃O₄@SiO₂ catalysts without a core–shell structure. The T_50% and T_90% of Pd(PdO)/Co₃O₄@SiO₂ are 357 °C and 445 °C, respectively, which decrease by 67 °C and 55 °C in comparison with those of Pd(PdO)/SiO₂. Extensive characterization demonstrates that the bimetallic oxide core–shell structure can effectively enhance the metal interaction between Pd and Co, which can weaken the strength of the Co–O bond in Pd(PdO)/Co₃O₄@SiO₂. The weakening of the Co–O bond could promote the release of more lattice oxygen species to participate in the C–H breaking, resulting in superior catalytic performance in methane combustion at low temperature.