Assemble of Bi-doped TiO onto 2D MoS: an efficient p-n heterojunction for photocatalytic H generation under visible light.

Fabrication of noble-metal-free, efficient and stable hybrid photocatalyst is essential to address the rapidly growing energy crisis and environmental pollution. Here, MoS has been used as the co-catalyst on Bi-doped TiO to form a novel heterostructure to increase the utilization of the photogenerated charge carriers for improving photocatalytic H evolution activity through water reduction. Significantly increased photocatalytic H generation has been achieved on the optimized MoS/Bi-TiO nanocomposite (∼512 μmol g) after 4 h of visible light illumination, which is nine times higher than that of the pristine TiO (∼57 μmol g). The measurements of photocurrent, charge transfer resistance and photo-stability of MoS/Bi-TiO photoanode imply that charge separation efficiency has been improved in comparison to the pure MoS and TiO photoanodes. Further, the Mott-Schottky study confirmed that a p-n heterojunction has been formed between n-type MoS and p-type Bi-doped TiO, which provides a potential gradient to increase charge separation and transfer efficiency. On the basis of these experimental results, this enhanced photocatalytic activity of MoS/Bi-TiO heterostructures could be ascribed to the significant visible light absorption and the efficient charge carrier separation. Thus, this work demonstrates the effect of p-n junction for achieving high H evolution activity and photoelectrochemical water oxidation under visible light illumination.