Cu(II) Oxide Amorphous Nanoclusters Grafted Ti³⁺ Self-Doped TiO₂: An Efficient Visible Light Photocatalyst

Ti 3+ self-doped TiO 2 was prepared by a facile one-step thermal oxidation of Ti 2 O 3 and TiO 2 mixture in air. Electron spin resonance (ESR) spectra confirmed the presence of Ti 3+ in this sample. Ti 3+ states caused a visible light absorption, which is originated from the isolated band in its forbidden gap. Although the photocatalytic activity of this Ti 3+ self-doped TiO 2 was negligible even under the UV light, its UV and visible light activities were drastically increased by the grafting of Cu(II) oxide amorphous clusters with a size of around 2 nm as a co-catalyst. Consequently, the photocatalytic decomposition of gaseous 2-propanol (IPA) into CO 2 with a maximum generation rate of 0.20 μmol/h and a quantum efficiency of 10.8% is achieved, under the visible light irradiation. Its efficient visible light activity is highly stable in air and can be repeatedly used for a long term.