5.1% Apparent quantum efficiency for stable hydrogen generation over eosin-sensitized CuO/TiO2 photocatalyst under visible light irradiation

A dye-sensitized CuO incorporated TiO2 catalyst was found to be an active photocatalyst for the photocatalytic hydrogen production from water under visible light (> 420 nm) irradiation in the presence of electron donors such as triethanolamine, acetonitrile and triethylamine. The stronger adsorption of eosin Y on the CuO incorporated TiO2 catalyst by multidentate complexation than on pure TiO2 was proved by the method of spectrophotometry, namely, the addition of CuO strongly improved the adsorption capability of TiO2 toward eosin dye and this effect led to a high quantum efficiency of eosin-sensitized CuO/TiO2 for photocatalytic water splitting. The electrons excited from the sensitizer molecules which were strongly adsorbed both on TiO2 and CuO by the visible light injected into the conduction band (CB) of both TiO2 and CuO, the electrons in CB of TiO2 subsequently transferred to CB of CuO, which resulted in a build-up of excess electrons in the conduction band of CuO. Consequently, the accumulation of excess electrons in CuO causes a negative shift in the Fermi level of CuO. As a result of that, the significant enhancement of apparent quantum yield (∼5.1%) and a good stability was obtained over the dye-sensitized 1.0 wt% CuO/TiO2 photocatalyst.