Assemble of Bi-doped TiO <sub>2</sub> onto 2D MoS <sub>2</sub> : an efficient p–n heterojunction for photocatalytic H <sub>2</sub> generation under visible light
Susmita Bera, Ankita Kumari, Srabanti Ghosh, Rajendra N. Basu
Abstract
Abstract Fabrication of noble‐metal‐free, efficient and stable hybrid photocatalyst is essential to address the rapidly growing energy crisis and environmental pollution. Here, MoS 2 has been used as the co-catalyst on Bi-doped TiO 2 to form a novel heterostructure to increase the utilization of the photogenerated charge carriers for improving photocatalytic H 2 evolution activity through water reduction. Significantly increased photocatalytic H 2 generation has been achieved on the optimized MoS 2 /Bi-TiO 2 nanocomposite (∼512 μ mol g –1 ) after 4 h of visible light illumination, which is nine times higher than that of the pristine TiO 2 (∼57 μ mol g –1 ). The measurements of photocurrent, charge transfer resistance and photo-stability of MoS 2 /Bi-TiO 2 photoanode imply that charge separation efficiency has been improved in comparison to the pure MoS 2 and TiO 2 photoanodes. Further, the Mott–Schottky study confirmed that a p–n heterojunction has been formed between n-type MoS 2 and p-type Bi-doped TiO 2 , 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 2 /Bi-TiO 2 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 2 evolution activity and photoelectrochemical water oxidation under visible light illumination.