Synthesis of g-C3N4 microrods with superficial C, N dual vacancies for enhanced photocatalytic organic pollutant removal and H2O2 production

Abstract

The g-C3N4 (CN) microrods with superficial C, N dual vacancies were synthesized by facial thermal polymerization of melamine--cyanuric acid supramolecular (MCS) precursors under H2 flow. Compared with bulk g-C3N4 (BCN), the as-synthesized defective CN microrods with an increased specific surface area exhibit an enhanced photocatalytic performance with a kinetic constant (K) of ~0.19 min−1 for RhB degradation and an ~718.36 µmol g−1h−1 for H2O2 production rate, which are about~17-fold and ~3-fold higher than that of BCN, respectively. The C, N dual vacancies are very effective in reducing the bandgap and inhibiting carrier recombination. The pivotal active species in RhB degradation is determined to be·O2-, and the pathway of H2O2 production is confirmed as a sequential two-step single-electron reduction. The results have provided a great potential way to promote the practical application of CN for photocatalytic organic pollutant removal and H2O2 production.