Photocatalytic Oxidative Coupling of Methane over Au1Ag Single‐Atom Alloy Modified ZnO with Oxygen and Water Vapor: Synergy of Gold and Silver

Abstract C−H dissociation and C−C coupling are two key steps in converting CH 4 into multi‐carbon compounds. Here we report a synergy of Au and Ag to greatly promote C 2 H 6 formation over Au 1 Ag single‐atom alloy nanoparticles (Au 1 Ag NPs)‐modified ZnO catalyst via photocatalytic oxidative coupling of methane (POCM) with O 2 and H 2 O. Atomically dispersed Au in Au 1 Ag NPs effectively promotes the dissociation of O 2 and H 2 O into *OOH, promoting C−H activation of CH 4 on the photogenerated O − to form *CH 3 . Electron‐deficient Au single atoms, as hopping ladders, also facilitate the migration of electron donor *CH 3 from ZnO to Au 1 Ag NPs. Finally, *CH 3 coupling can readily occur on Ag atoms of Au 1 Ag NPs. An excellent C 2 H 6 yield of 14.0 mmol g −1 h −1 with a selectivity of 79 % and an apparent quantum yield of 14.6 % at 350 nm is obtained via POCM with O 2 and H 2 O, which is at least two times that of the photocatalytic system. The bimetallic synergistic strategy offers guidance for future catalyst design for POCM with O 2 and H 2 O.