The enhanced photocatalytic activity of Zn2+ doped TiO2 for hydrogen generation under artificial sunlight irradiation prepared by sol–gel method

Novel Zn2+ doped TiO2 photocatalysts were synthesized by a simple sol–gel method. X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma optical emission spectrometry, Brunauer–Emmett–Teller method and Photoluminescence spectra were employed to examine the phase structure, morphology and optical properties of the synthesized samples. Their photocatalytic activities were evaluated by spitting water under artificial sunlight irradiation. In contrast with pure TiO2, the Zn2+–TiO2 samples showed enhanced photocatalytic properties. When TiO2 was doped with 1 wt% Zn2+, it showed the optimal photocatalytic activity with the amount of hydrogen evolution of 180 μmol h−1, which was as about seven times as that for pure TiO2. For the Zn2+–TiO2, Zn2+ can improve the separation ratio of photoexcited electrons–holes and leads to the high photocatalytic activity of TiO2.