Effects of charge balance with Na+ on SrTiO3:Mo6+ prepared by spray pyrolysis for H2 evolution under visible light irradiation

Photocatalyst powders of SrTi1−xMoxO3 and Sr1−2xNa2xTi1−xMoxO3 were prepared by spray pyrolysis for hydrogen evolution for the first time from aqueous methanol solution under visible light irradiation. The co-doping of Mo6+/Na+ ions resulted in increase of BET surface area and pore volume, and formation of unique morphology with wrinkled, furrowed and porous surface, without significant distortion of lattice structure of host material. The hydrogen evolution rate of Sr1−2xNa2xTi1−xMoxO3 photocatalyst was enhanced up to 1115.8 μmol g−1 h−1 with an induction period of 1 h under visible light irradiation, which was 1.5 times higher than that of SrTi1−xMoxO3. The co-dopant Na+ ion contributed to the charge balance in the host material by compromising the excess positive charge of Mo6+, which was effective for enhancing the hydrogen evolution rate. The optimum composition of photocatalyst corresponding to the maximum hydrogen evolution rate was Sr1−2xNa2xTi1−xMoxO3 (x = 0.004).