Microwave heating assisted synthesis of novel SnSe/g-C3N4 composites for effective photocatalytic H2 production

Abstract Novel SnSe/g-C 3 N 4 photocatalysts were one-step synthesized via a microwave heating assisted process in 35 minutes with SnSe and melamine as precursors. The as-synthesized SnSe/g-C 3 N 4 worked very well in H 2 evolution via photocatalysis. Under simulated sunlight, the best SnSe/g-C 3 N 4 sample displayed a H 2 -production velocity of 1064 μmol g −1  h −1 , which is 1.8 folds faster than that of neat g-C 3 N 4 . Similar promotion effect was also observed under visible light. To reveal the nature behind the high photoactivity, a thorough investigation was performed. XRD and XPS experiments proved the binary constitution of the composite. DRS experiment demonstrated that the addition of SnSe improved the photoabsorption performance. N 2 -adsorption analysis showed that the SnSe/g-C 3 N 4 photocatalyst presented similar surface area as g-C 3 N 4 . TEM experiments showed that some bulk SnSe were spontaneously decomposed to nanoparticles and finely dispersed in g-C 3 N 4 during the microwave heating process. These SnSe nanoparticles were believed to be the active phase and constructed a heterojunction structure with g-C 3 N 4 , resulting in the enhanced charge separation. This conclusion was considered as the key factor leading to the high H 2 -evolution performance and was further confirmed by the PL, EIS, and PC experiments. The present work provides a feasible and rapid method for the construction of g-C 3 N 4 based photocatalysts.