1T phase boosted MoSe2/pg-C3N4 with Z-scheme heterojunction for enhanced photocatalytic degradation of contaminants

An ordered 1T/2H MoSe2 possessed few-layers nanosheets structure was synthesized by a NaBH4-assisted hydrothermal method. Further, 1T/2H MoSe2 was integrated with proton g-C3N4 via solvothermal method, forming a novel 2D/2D heterostructure composite (1T/2H MoSe2/pg-C3N4) with Z-scheme heterojunction. 1T/2H MoSe2/pg-C3N4 had narrower bandgap, abundant active sites, as well as better photocurrent response and conductivity, confirmed by spectroscopic and electrochemical characterizations. Consequently, the optimal 1T/2H MoSe2/pg-C3N4 at 1 wt% MoSe2 loading showed enhanced TC (RhB) photodegrading rate of 92% (99%), within 80 min (45 min) of simulated solar light irradiation, being 3.0 (3.4) and 1.2 (1.2) times than that of pg-C3N4 and 2H MoSe2/pg-C3N4, respectively. Additionally, active species trapping experiments indicated that center dot O-2(-) and h(+) were the main species of contaminants degradation over 1T/2H MoSe2/pg-C3N4. Combining with DRS, Mott-Schottky and VB XPS analysis, a reasonable 1T phase boosted Z-scheme MoSe2-based heterojunction mechanism was proposed.