Roles of oxygen vacancies in surface plasmon resonance photoelectrocatalytic water oxidation

The extremely short lifetime of plasmon-induced charges is a huge chal-lenge to surface plasmon resonance photocatalytic water oxidation. Here, we report that increasing oxygen vacancies (VO) in Au/TiO2-x can greatly enhance the external quantum efficiency of plasmon-induced water oxidation from 0.03% to 1.52% at 520 nm. The increased VO can achieve efficient transportation of plasmonic elec-trons in the conduction band of TiO2-x with enhanced conductivity and can boost the oxygen evolution kinetics of Au/TiO2-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 TiO2-x, which originate from VO at the interface of Au/TiO2-x. This process could enrich holes at the interface, making it possible to collect multiple holes for water oxidation. The syn-chronous functions in hole capture and water molecule adsorption enable VO to be efficient catalytic sites for plasmon-induced water oxidation.