Lattice Oxygen in Photocatalytic Gas-Solid Reactions: Participator vs. Dominator

Lattice-oxygen activation has emerged as a popular strategy for optimizing the performance and selectivity of oxide-based thermocatalysis and electrolysis. However, the significance of lattice oxygen in oxide photocatalysts has been ignored, particularly in gas-solid reactions. Here, using methane oxidation over a Ru₁@ZnO single-atom photocatalyst as the prototypical reaction and via ¹⁸O isotope labelling techniques, we found that lattice oxygen can directly participate in gas-solid reactions. Lattice oxygen played a dominant role in the photocatalytic reaction, as determined by estimating the kinetic constants in the initial stage. Furthermore, we discovered that dynamic diffusion between O₂ and lattice oxygen proceeded even in the absence of targeted reactants. Finally, single-atom Ru can facilitate the activation of adsorbed O₂ and the subsequent regeneration of consumed lattice oxygen, thus ensuring high catalyst activity and stability. The results provide guidance for next-generation oxide photocatalysts with improved activities and selectivities.