Metal-organic frameworks-derived CoFeN-NC materials with the enhanced catalytic activity and selectivity for the degradation of organic dyes via adsorption and heterogeneous photo-Fenton

Nanoscale iron-based materials are widely used as photocatalytic materials for catalytic oxidative degradation of organic dyes in water. Here, a series of MOFs derived nitrogen doped cobalt iron bimetallic carbon composite nanomaterials (CoxFe1-xN-NCs) were prepared by self-assembly and annealing treatment, and their application in the removal of organic dyes in water was investigated by the synergistic effect of adsorption and photo-Fenton. The study found that the Co0.8Fe0.2N-NC exhibit superior catalytic performance for different types of organic dyes. For example, when the concentration of MB was 40 mg L-1, the degradation rate constant was 3.88 x 10(-2) min(-1), which were 2.9 and 25.2 times the corresponding values of the Fenton-like and photocatalytic system, respectively. Meanwhile, compared with azo dyes Methyl Orange and Congo Red (MO and CR), Co0.8Fe0.2N-NC has obvious selective catalysis for non-azo dyes Methylene Blue, Malachite Green, Rhodamine B and Neutral Red (MB, MG, RhB and NR). Moreover, the reaction of cobalt iron active centers with hydrogen peroxide (H2O2) further promotes the generation of active substances (.OH, .O-2(-) and h(+)), speeding up the degradation of organic dyes. These results suggest that the synergistic effect of adsorption and photo-Fenton may provide new clues for the treatment of organic pollutants in wastewater.