Pyrrole nitrogen coordinated Fe on carbon nitride mediated singlet oxygen formation for efficient degradation of 2-mercaptobenzothiazole

Abstract

We report a rational and scalable synthetic approach to prepare Fe-decorated carbon nitride materials assisted by carbonized polyamine (C-Fe@PDA-CN). The material exhibited extremely high activity and stability for the degradation of 2-mercaptobenzothiazole (MBT) and other organic pollutants (phenol, BPA, MB, and RhB) under visible light irradiation. Furthermore, escape from CN to C-Fe@PDA provides an electron transfer channel to facilitate carrier separation and accelerate the generation of active species, as confirmed by photoluminescence, photoelectrochemical, and electron paramagnetic resonance (EPR). Fe exists in the material coordinated with the pyrrole nitrogen of polydopamine. This coordination structure is conducive to the generation of singlet oxygen (1O2). It is confirmed by steady-state phosphorescence spectroscopy (PH) that 1O2 originates from electron transfer. Superoxide radicals are generated by electron transfer and then oxidized into 1O2 by holes. The main intermediates of MBT degradation were identified by the LC-MS method, and a possible photocatalytic mechanism based on quenching experiments and EPR tests was proposed.