Preparation of highly N-doped CoFeN by pyrolysis g-C3N4 for markedly enhanced Fenton degradation of MO and TC-HCl under visible illumination

In the study, highly N-doped metal organic framework (MOFs) derived CoFeN photocatalysts (CoFeN-N) were successfully prepared by using carbon nitride (g-C 3 N 4 ) nanosheets as the support with simultaneous additional N source. CoFeN-N activated hydrogen peroxide (H 2 O 2 ) was used to remove Methyl orange (MO) and Tetracycline hydrochloride (TC-HCl) in water under simulated visible light . N doping improves the photo-Fenton degradation ability of CoFeN to varying degrees, and the photocatalyst with the best performance is CoFeN-N2. The degradation rate constants (K) of MO and TC-HCl are 1.8 and 5.1 times of CoFeN, respectively. CoFeN-N2 did not significantly inhibit the degradation efficiency of organic pollutants under acidic, neutral and alkaline conditions. Meanwhile, the presence of coexisting anions (Cl − 、HCO 3 - and HPO 4 2- ) in water similarly does not obviously reduce the degradation ability of CoFeN-N2 for MO and TC-HCl, which indicates the excellent anti-interference ability of the prepared photocatalyst. The TOC test results indicate that CoFeN-N2 has excellent mineralization ability for organic contaminants. In addition, hydroxyl radicals , superoxide radicals, and holes (·OH, ·O 2 - and h + ) were demonstrated to be the primary active species for the degradation of organic pollutants by CoFeN-N2 through free radical trapping experiments and EPR tests. This work provides an attractive strategy for the preparation of highly N-doped photocatalysts and the efficient removal of organic pollutants from water by photo-Fenton coupling.