Sulfur-doped g-C3N4/rGO porous nanosheets for highly efficient photocatalytic degradation of refractory contaminants

Graphitic carbon nitride (g-C3N4, CN) has attracted increasing interests in the field of photocatalysis due to its high visible-light-response. However, its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(VI) and Rhodamine B (RhB) etc. Herein, we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide (rGO) porous nanosheet (S-CN/rGO PNs) via a supramolecular self-assembling followed by a solvothermal treatment. The as-prepared porous S-CN/rGO PNs are stable with high specific surface area ∼188.5 m2g-1 and exhibit a significantly enhanced photocatalytic activity of ∼17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(VI) under visible light irradiation, respectively. Typically, 50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs. The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers. The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.