Photocatalytic Remote Oxidation Induced by Visible Light

Photocatalytic remote oxidation was examined under visible light by using WO3-based photocatalysts: WO3, WO3 modified with Pt nanoparticles (Pt–WO3), and WO3 modified with Cu(II) ions (Cu(II)–WO3). Alkyl chains on a glass plate separated from the photocatalyst by 7.5 μm thick air were removed in 40 min under visible light (≥420 nm, ∼100 mW cm–2). Among the photocatalysts examined, Pt–WO3 exhibits the highest remote oxidation activity. Its activity is higher than that of TiO2 modified with Pt nanoparticles in the wavelength range 360–460 nm. It is likely that Pt–WO3 emits •OH under visible light, which diffuses in air and attacks alkyl chains, whereas the major path of the remote oxidation induced by UV light involves emission of H2O2 and its photocleavage into •OH. Remote storage of oxidative energy in Ni(OH)2 is also possible by using visible light-irradiated Pt–WO3.