Iron oxide clusters on g-C3N4 promote the electron–hole separation in photo-Fenton reaction for efficient degradation of wastewater

Improving the efficiency of photocatalytic reaction is a long-term problem. Recently, the advantages of combining photocatalytic reaction with other reactions have become apparent. In this work, trinuclear iron cluster (Fe3) have been integrated on graphitic carbon nitride (g-C3N4) nanosheets, which were converted to α-Fe2O3/g-C3N4 by calcination. It can effectively utilize the synergistic effect of visible light and Fenton oxidation to carry out photo-Fenton synergistic catalytic degradation of pollutants, and the degradation rate of CFCN to tetracycline hydrochloride exceeded 80% within 45 min, which is 9 times higher than that of pure g-C3N4. In four cycles, the catalytic effect of the reaction remained stable. The enhanced catalytic performance can be attributed to the separation of electron–hole pairs due to the conversion of Fe3+ and Fe2+ in the Fenton reaction, allowing a large number of holes to be used directly for the degradation of tetracycline. It is worth mentioning that this catalyst can still function under high salinity conditions and it also has the ability to degrade some dyes (MB and RhB). This work will promote a new understanding of the degradation of organic contaminants by supported cluster catalysts, and prove the high efficiency of photo-Fenton synergistic catalysis.Graphical abstract