Ag2Se nanoparticles anchored on S-g-C3N4 nanosheets towards efficient photocatalytic tetracycline hydrochloride removal and H2 generation

To improve the stability of Ag based co-catalysts and to increase the photocatalytic performance of graphitic carbon nitride (g-C 3 N 4 ), Ag 2 Se nanoparticles were grown onto superior thin sulfur-doped g-C 3 N 4 nanosheets which was fabricated via two-step thermal polymerization at high temperature. Ultrathin S-doped g-C 3 N 4 nanosheets were prepared via two-step thermal polymerization using melamine and thiourea. The ratios of Ag 2 Se were adjusted to fabricate a series of Ag 2 Se/S-g-C 3 N 4 (Ag 2 Se/SCN) composite samples by controlled solvothermal synthesis. S-doping plays an important role in mono-dispersion of Ag 2 Se nanoparticles on S-g-C 3 N 4 nanosheets because of the control of growth sites. The photocatalytic removal of tetracycline hydrochloride test indicates that sample Ag 2 Se/SCN-3 with Ag 2 Se loading of 3 % reveals the best removal effect, in which tetracycline hydrochloride of 60 % is removed within 60 min. Photocatalytic hydrogen generation test results without co-catalyst addition demonstrate that sample Ag 2 Se/SCN-3 exhibits the best H 2 evolution rate of 2116.35 μmol·g −1 ·h −1 , which is 3.8 times of that of pure carbon nitride. The photocatalytic mechanism tests suggest that Schottky heterojunctions are formed in the Ag 2 Se/S-g-C 3 N 4 composites. The formation of Schottky heterojunctions improved the separation efficiency of photogenerated charge carriers. The incorporation of Ag 2 Se nanoparticles (as the co-catalyst) on S-g-C 3 N 4 nanosheets is the key for drastically improving the photocatalytic performance and eliminating the use of Pt co-catalyst during the photocatalytic processes.