Ag‐ZnO Nanoflowers Enable Highly Selective Photocatalytic Conversion of CH4 to CH3OH at Atmospheric Pressure: Unraveling Reactive Interfaces and Intermediate Control

At atmospheric pressure, the main challenge in the photocatalytic oxidation of CH4 to CH3OH is to absorb and activate the inert C─H bond while preventing excessive oxidation of CH3OH. In this study, metal-supported ZnO nanoflowers (Ag-ZnO) are designed to produce abundant active interfacial oxygen sites for CH4 oxidation at atmospheric pressure, with a CH3OH yield reaching 1300 µmol gcat -1 h-1 and the selectivity is 94%. DFT calculation and in situ analysis show that the addition of Ag regulates the electron state density and band center of O, which is beneficial to the adsorption of CH4, and decreases the dissociation energy barrier of C─H bond at OL(Lattice oxygen) site. The further selective conversion of ·CH3 to CH3OH involves two different pathways: one pathway consists of the oxidation of ·CH3 by OL, and the other pathway is the combination of ·CH3 and ·OH generated from dissolved O2 (0.28 mm) in water. Notably, in the photochemical flow device, the yield of CH3OH is increased to 5200 µmol gcat -1 h-1 and the selectivity is close to 100%. This work offers valuable insights into reactive interfaces, morphological engineering, and the control of intermediate evolution toward selective conversion of CH4 to oxygenates at atmospheric pressure.