Although computational studies have demonstrated that metal ion doping can effectively narrow the bandgap of TiO2,the visible-light photoactivity of metal-doped TiO2 photoanodes is still far from satisfac-tory.Herein,we report an effective strategy to activate the visible-light photoactivity of chromium-implanted TiO2 via the incorporation of oxygen vacancies.The chromium-doped TiO2 activated by oxygen vacancies(Cr-TiO2-vac)exhibited an incident photon-to-electron conversion efficiency(IPCE)of~6.8%at 450 nm,which is one of the best values reported for metal-doped TiO2.Moreover,Cr-Ti02-vac showed no obvious photocurrent decay after 100 h under visible-light illumination.