Preparation of C-doped g-C3N4 by Co-polycondensation of melamine and sucrose for improved photocatalytic H2 evolution

g-C3N4, a well-known semiconductor is widely used for photocatalysis because of its renowned and special properties. It is a nonmetallic polymeric material that is abundant in sources and easy to prepare, making it an attractive choice for photocatalysis that responds to visible light. However, due to various intrinsic structural and chemical drawbacks, it is very far from further applications. Herein, we used sucrose to modify the physicochemical characteristics of ordinary g-C3N4 to prepare a carbon self-doped g-C3N4 (Cn-MA) material through co-polycondensation with melamine and applied it for hydrogen production. The characterization showed that the addition of sucrose resulted in a narrowed band gap, widened absorption range, enhanced photoresponse, and photogenerated charge carrier separation. Furthermore, the prepared material was applied for hydrogen production activity, which revealed that it has higher photocatalytic performance than pristine g-C3N4. The H-2 production rate of the optimized material (C-7.5-MA) was recorded as 7.3 times greater than that of pure g-C3N4. Through cycling tests, the stability of C-7.5-MA was examined. The results showed that, even after four consecutive cycles, no apparent drop in its performance was observed. Additionally, here the mechanism of hydrogen production is also discussed.