Roles of oxygen vacancies in surface plasmon resonance photoelectrocatalytic water oxidation

The extremely short lifetime of plasmon-induced charges is a huge challenge to surface plasmon resonance photocatalytic water oxidation. Here, we report that increasing oxygen vacancies ( V O ) in Au/TiO 2-x can greatly enhance the external quantum efficiency of plasmon-induced water oxidation from 0.03% to 1.52% at 520 nm. The increased V O can achieve efficient transportation of plasmonic electrons in the conduction band of TiO 2-x with enhanced conductivity and can boost the oxygen evolution kinetics of Au/TiO 2-x . The dynamics of plasmonic electrons derived from interband transition reveal that holes in the d-band of Au nanoparticles (NPs) can transfer to the defect states near the valence band of TiO 2-x , which originate from V O at the interface of Au/TiO 2-x . This process could enrich holes at the interface, making it possible to collect multiple holes for water oxidation. The synchronous functions in hole capture and water molecule adsorption enable V O to be efficient catalytic sites for plasmon-induced water oxidation.