Photocatalysis-Fenton mechanism of rGO-enhanced Fe-doped carbon nitride with boosted degradation performance towards rhodamine B

A photo-Fenton catalyst Fe‑carbon nitride (g-C3N4)/reduced graphene oxide (rGO) (labeled as FNGO) was prepared via two-step calcination thermal polymerization. rGO as a carrier of Fe-g-C3N4 accelerated the charge transfer and improved the reduction of Fe (III) as compared those of the binary Fe-g-C3N4 catalyst. The FNGO catalyst maintained a high surface area of 264.7 m2/g and its charge transfer rate was 2.77 times higher than Fe-g-C3N4. The decreasing transient photocurrent and increasing electrode resistance of FNGO, Fe-g-C3N4 and g-C3N4 confirm the positive synergistic effect of FeN coordination and rGO in charge transfer. Under the synergistic of visible light irradiation and H2O2, the excellent degradation performance of FNGO towards rhodamine B was achieved (95.3 % removal) at Fe-doping content of 10 wt%, rGO loading content of 0.5 % and H2O2 addition of 1.5 mM. Hydroxyl radicals played a dominant role in the photocatalysis-Fenton system, which was related to the coordination of FeN, the carrier off-domain of rGO, and the Fe (III)/Fe (II) cycle promoted by photogenerated electron and superoxide radicals. The FNGO had a high stability, a wide pH adaptation (3– 11) and a low Fe-leaching. This novel ternary light-driven photo-Fenton catalyst of FNGO enabled efficient decontamination during advanced treatment of wastewater.