A novel solar photo-Fenton system with self-synthesizing H2O2: Enhanced photo-induced catalytic performances and mechanism insights

Abstract To solve problems of consecutive H2O2 external supplement and reutilization difficult of free Fe2+ ion in traditional homogeneous photo-Fenton, an efficient solar photo-Fenton system with self-supplying H2O2 was developed based on a heterogeneous catalyst of α-Fe2O3/g-C3N4. The microstructure, physicochemical and photoelectric properties of the optimal α-Fe2O3/g-C3N4 were characterized. It was found that the introduced α-Fe2O3 significantly enhanced the photoeletrochemical performances of g-C3N4. Rhodamine B and tetracycline hydrochloride were degraded in this solar photo-Fenton system with α-Fe2O3/g-C3N4, and the corresponding degradation rates reached to 96% (in 90 min) and 95% (in 150 min) at neutral pH circumstance respectively, which were much higher than that of single g-C3N4 and α-Fe2O3. The efficient degradation performance was attributed to the effective separation and rapid transfer of photo-generated charge carriers derived from classic Z-scheme type. Accordingly, it was deduced that H2O2 can produce on the g-C3N4 surface firstly under simulated solar irradiation, and the efficient removal of contaminant could be ascribed to oxidation by amount of ·OH predominantly derived from H2O2 decomposition on the α-Fe2O3, which was verified by trapping experiments and EPR analysis. In addition, ·O2− and h+ also played supporting roles. The main significance of this study gives a new insight into photo-Fenton.