Oxygen vacancy configuration in confined BiVO4-Bi2S3 heterostructures promotes photocatalytic oxidation of NO

Oxygen vacancy configuration is a promising means for tuning the electronic structure and determining the adsorption/desorption mode of the reactants in photocatalytic NOx oxidation. We report here that the formation of oxygen vacancies (OVs) can activate free NO and O2 molecules via a changed oxidation route, leading to fast conversion of NO into NO3-. The boosted NO oxidation reaction was conducted on novel OVs-induced BiVO4-Bi2S3 heterojunctions with the shape of double-deck hollow nanospheres assembled by a hard-templating treatment, followed by an annealing process. Abundant OVs were incorporated into the lattice of the as-synthesized heterojunctions, which significantly decreased the recombination level of the photo-exited carriers, leading to the promotion of the exchange of adsorbed ambiance oxygen and lattice oxygen, and the formation of reactive oxygen species and the final highly-efficient removal of NO under visible-light illumination. This work verifies the role of defective and hierarchical interface configuration on catalytic NOx oxidation and provides a viable methodology for the discovery of advanced photocatalysts via surface engineering.