S/P co-doped g-C3N4 with secondary calcination for excellent photocatalytic performance

The metal-free and low-cost g-C3N4 has received a lot of attention from researchers as a photocatalyst to solve environmental and energy problems. However, bulk g-C3N4 suffers from limited light absorption, few reactive sites and easy recombination of photogenerated electrons and holes, resulting in unsatisfactory photocatalytic performance. In this study, g-C3N4 nanosheets with excellent photodegradation performance were successfully fabricated by a combination of S/P co-doping and secondary calcination modifications. The modified g-C3N4 could degrade 99.4% rhodamine B (30 mg L−1) in only 4 min, which was 15 times higher than that of pure g-C3N4 due to the synergistic effect of bi-element doping and secondary calcination. Furthermore, experiments using photocatalytic water splitting for hydrogen production have shown different results, demonstrating that the critical factor is different from the photodegradation reaction.This paper provides an effective and feasible novel idea for the modification of g-C3N4.