Efficient Photocatalytic Methane Conversion to Liquid Oxygenates by Constructing Charge-Directed Transfer Pathways.

Abstract

Efficient methane (CH₄) conversion remains challenging because of the inert C-H bond and the complexity of the multistep reaction process. Herein, we designed and fabricated a C/ZnO/Pd photocatalyst for the selective methane oxidation to C₁ products, achieving a C₁ production rate of 55.1 mmol·g_cat^-1·h^-1 and 11,020 mmol·g_Pd^-1·h^-1, with a selectivity of up to 98%. Mechanistic studies reveal that the high performance arises from a directional charge transfer strategy enabled by the synergistic integration of Pd and the carbon layer. The carbon layer provides a carbon-mediated electron-transfer channel, while the Pd interface introduces a Pd-mediated hole-transfer pathway. These two components work in concert to promote directional charge transfer and suppress reverse migration. This asymmetric charge behavior further gives rise to a spatially cooperative pathway for methane conversion and oxygen activation. The generality of this strategy is supported by extending it to different metal active sites and an alternative route for constructing the carbon layer. This work provides a strategy for designing high-performance photocatalysts for methane valorization.