Defected ZnS/bulk g–C3N4 heterojunction with enhanced photocatalytic activity for dyes oxidation and Cr (Ⅵ) reduction

Defect–rich zinc sulfide (ZnS, ZS) was successfully synthesized by the slow release of S source from glutathione (GSH) to coordinate with Zn 2+ at high temperature. Based on this, a novel ZnS/g–C 3 N 4 (ZSCN) heterojunction with high catalytic activity was fabricated through facile in–situ hydrothermal method . The removal rates of Rhodamine B (RhB), methyl orange (MO), methylene blue (MB) and Cr 6+ for ZSCN–0.05 with the highest catalytic activity under full–spectrum illumination were 13.0, 53.2, 2.0 and 11.6 times of g–C 3 N 4 (CN), and 3.6, 14.8, 1.2 and 3.9 times of ZS, respectively. While, under visible–light illumination, ZSCN–0.075 exhibited the best photodegradation performance for RhB, and the degradation rate was 5.2 and 19.3 times to CN and ZS, respectively. The enhanced photocatalytic activity of ZSCN heterojunction could be attributed to the synergistic effect between CN and ZS: ZS with defect-rich enhanced the absorption intensity of ZSCN in the ultraviolet, and CN broaden the spectral response range of ZSCN. Moreover photoluminescence spectrum confirmed that the formation of ZSCN heterojunction could effectively inhibit the recombination of photogenerated electrons and holes, and accelerate the electron transfer at its interface.