Nitrogen-doped SrTiO3/TiO2 composite photocatalysts for hydrogen production under visible light irradiation

Nitrogen-doped SrTiO3 powders were prepared by solid phase method, and further combined with TiO2 by sol–gel method. Then Pt particles were deposited to prepare Pt-loaded composite powders by hydrogen reduction method. These obtained powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra, thermogravimetric–differential thermal, ultraviolet (UV)–vis diffuse reflectance spectra and fluorescence spectra techniques. Photocatalytic production of hydrogen from oxalic acid solution was used as the probe reaction to evaluate the photocatalytic activity of hydrogen production under visible light in detail from aspects of different calcination temperatures, and different contents of metal Pt. The result demonstrates that when the calcination temperature is 400 °C, the optimized photocatalytic activity of hydrogen production under visible light can be achieved. Pt depositing greatly improves the photocatalytic activity, and the average hydrogen production rate is up to 5.1 mmol g cat−1 h−1 with 2 wt.% loaded Pt.