In- situ solid-phase fabrication of Ag/AgX (X=Cl, Br, I)/g-C3N4 composites for enhanced visible-light hydrogen evolution

In this work, a series of Ag/AgX (X = Cl, Br, I)/g-C 3 N 4 (Ag/AgX/CN) composites were successfully fabricated by an in-situ solid phase method. The morphology and structure, photoluminescence and photoelectrochemical properties of composites were investigated in detail. The as-prepared Ag/AgX/CN composites were used as H 2 evolution photocatalysts under visible-light irradiation with a sacrificial agent . The experimental results revealed that Ag/AgI/CN-4 composite possesses highest-H 2 evolution rate (up to 59.22 μmol g −1  h −1 ) which are approximately 31 times higher than that of pure g-C 3 N 4 (1.94 μmol g −1  h −1 ). In addition, Ag/AgCl/CN-4 and Ag/AgBr/CN-4 composites also present high photocatalytic activities yielding, 26.39 and 18.05 μmol H2 g −1 h −1 , respectively. The enhanced photocatalytic activities of Ag/AgI/CN-4 composite might be attributed to the synergistic effect between Ag/AgI nanoparticles and g-C 3 N 4 and the localized surface plasmon resonance effect of metallic Ag. Moreover, Ag/AgI/CN-4 composite showed excellent recyclability and stability after five cycling photocatalytic tests (about 25 h). Furthermore, the possible photocatalytic mechanism of Ag/AgI/CN composites is proposed.