Visible light driven photocatalysts with oxidative energy storage abilities

Visible light driven photocatalysts, N-doped TiO2, Fe(III)-modified TiO2, WO3, Cu(II)-modified WO3 and Pt nanoparticle-loaded WO3, were combined with Ni(OH)2 as an oxidative energy storage material, to overcome two serious limitations of TiO2 photocatalyst; it works only under light, and the light must contain UV. Among the photocatalysts examined, 1 wt% Pt-loaded WO3/Ni(OH)2 bilayer film exhibits the highest efficiency of oxidative energy storage under visible light (≥420 nm), sunlight and fluorescent light. The energy storage is possible even under 460 nm light. Other Pt-loaded WO3 (0.1–10 wt%), Fe(III)-modified TiO2 and Cu(II)-modified WO3 also exhibit energy storage abilities under visible light when combined with Ni(OH)2.