Hybridization of brookite TiO2 with g-C3N4: a visible-light-driven photocatalyst for As3+ oxidation, MO degradation and water splitting for hydrogen evolution

Abstract

This work gives a first report on the effective visible-light-driven photocatalyst of brookite TiO₂ (br-TiO₂) hybridized with g-C₃N₄. This hybrid was prepared via a facile calcination in air. When irradiated under visible light, all br-TiO₂/g-C₃N₄ hybrids showed an activity superior to the component g-C₃N₄ or br-TiO₂ in methyl orange (MO) degradation. The optimum photocatalytic activity of the hybrid br-TiO₂/g-C₃N₄ is higher than those of other types of TiO₂ (anatase and rutile) when hybridized with g-C₃N₄. Furthermore, the optimized hybrid, br-TiO₂/g-C₃N₄ (35 wt%), was successfully applied to toxic As³⁺ oxidation and water splitting for hydrogen generation under visible light. All these results clearly demonstrate that the hybridization of br-TiO₂ with g-C₃N₄ is highly promising for photocatalytic uses, which are barely accessible in previous literature. This abnormal observation is ascribed to the effective separation of the photo-generated carriers on the surfaces between the closely contacted br-TiO₂ and g-C₃N₄.