Yong Xu, Min Wang*, Qi Xie, Yuying Wang, Xuejing Cui, Luhua Jiang*

Nanomaterials and Electrocatalysis Laboratory, College of Materials and Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, P. R. China

Abstract

It is highly desirable to make full use of photogenerated charge carriers by elaborately designing highly-efficient multi-functional photocatalysts with a valuable and thermodynamically favorable oxidation reaction. Herein, a facile synthesis route is developed to obtain a boron-doped Zn_xCd_1-xS/Cd heterojunction with sulfur vacancies (B-ZCS_v/Cd-T) via NaBH₄ treatment. The optimized B-ZCS_v/Cd-T catalyst achieved a superior activity towards hydrogen evolution (5.10 μmol) by coupling with RhB degradation (87.48%) in dyeing waste water under visible light. Systematic investigation reveals that NaBH₄ treatment resulted in boron doping and simultaneously sulfur vacancies in B-ZCS_v/Cd-T, which consequently optimized the energy band structures to form a B-ZCS_v/Cd heterojunction, leading to (i) effective absorption of visible lights and (ii) enhanced separation/transfer efficiency of the photogenerated electron-hole pairs. This work provides an effective strategy to increase the photocatalytic activity of catalysts via modulating band structures and interfacial compatibility of heterojunction, and especially through coupling with a valuable and more thermodynamically favorable reaction.

Keywords: Zn_xCd_1-xS; H₂ evolution; sulfur vacancy; heterojunction; dyeing waste water