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 Fe N 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 Fe N, 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.