Photocatalytic Oxidative Coupling of Methane to Ethane Using Water and Oxygen on Ag3PO4-ZnO

Photocatalytic oxidative coupling is an effective wayof convertingCH(4) to high-value-added multi-carbon chemicals under mildconditions, where the breaking of the C-H bond is the mainrate-limiting step. In this paper, the Ag3PO4-ZnO heterostructure photocatalyst was synthesized for photocatalyticoxidative coupling of methane (OCM) to C2H6.In addition, an excellent C2H6 yield (16.62mmol g(-1) h(-1)) and a remarkableapparent quantum yield (15.8% at 350 nm) at 49:1 CH4/Airand 20% RH are obtained, which is more than three times that of thestate-of-the-art photocatalytic systems. Ag3PO4 improves the adsorption and dissociation ability of O-2 and H2O, benefiting the formation of surface hydroxylspecies. As a result, the C-H bond activation energy of CH4 on ZnO was obviously reduced. Meanwhile, the improved separationof photogenerated carriers on the Ag3PO4-ZnOheterostructure also accelerates the OCM process. Moreover, Ag nanoparticles(NPs) derived from Ag3PO4 reduction by photoelectronspromote the coupling of *CH3, which can inhibit the overoxidationof CH4 and increase C2H6 selectivity.This research provides a guide for the design of catalyst and reactionsystems in the photocatalytic OCM process. This work greatly promoted the photocatalyticconversionof CH4 to C2H6 from an enhanced photoelectricperformance and reaction kinetics under the coaction of oxygen andwater.

Automated summary

In this study, the Ag3PO4-ZnO heterostructure photocatalyst was successfully synthesized for photocatalytic oxidative coupling of methane. The catalyst exhibited excellent C2H6 yield and remarkable apparent quantum yield, surpassing state-of-the-art photocatalytic systems. The research provides insights for the design of catalysts and reaction systems in photocatalytic methane conversion.