Unprecedentedly efficient mineralization performance of photocatalysis-self-Fenton system towards organic pollutants over oxygen-doped porous g-C3N4 nanosheets

Herein, a photocatalysis-self-Fenton system was constructed to achieve unprecedentedly efficient degradation and mineralization performance towards organic pollutants. This system is based on oxygen-doped porous g-C3N4 nanosheets (OPCN) with high H2O2 yield and the added Fe3+. The corresponding degradation rate for 2,4-dichlorophenol was 11.5 and 9.9 times higher than that of bulk-g-C3N4-based photocatalysis and Fenton system, respectively, while the mineralization rate was 11.4 and 4.2 times higher, respectively. The excellent oxidation capacity was due to three reasons: (1) the porous nanosheet morphology and oxygen doping of HCNS accelerated the carriers transfer and provided more reactive sites for H2O2 synthesis; (2) Fe3+ was reduced into Fe2+ by photogenerated electrons, further inhibiting the charge recombination and promoting the cyclic conversion of Fe3+/Fe2+; (3) the high-efficiency utilization of in-situ generated H2O2 was realized via heterogeneous Fenton reaction, producing abundant •OH. This work provides a new strategy to develop g-C3N4-based photocatalysis-self-Fenton system for environmental remediation.