Fe-N coordination moieties regulate the defect formation in carbon nanomaterial for efficient peroxydisulfate activation: Significant role of surface complex

An iron (Fe)-modified carbon dots (CDs) doped ZIF-8 zeolite imidazole metal-organic frame pyrolyzed composite (5Fe@NC) was prepared and then evaluated as a peroxydisulfate (PDS) activator for the oxidative removal of organic pollutants. The 5Fe@NC/PDS system not only has a good recovery performance, wide pH adaptability, and low activation energy, but also is resistant to environmental interference. The quenching experiments, electron paramagnetic resonance (EPR) detection, and electrochemical analysis all revealed that unlike the widely reported singlet oxygen (1O2) dominated nonradical mechanism, an electron transfer process (ETP) involving a surface bound PDS complex played the main role in pollutants' degradation by 5Fe@NC/PDS system. The FeNx, defect, graphitic N and hydroxyl group (-OH) acting as active sites, prompted the 5Fe@NC-PDS complex to capture electrons (e- ) from acetaminophen (ACT). This study provides a new approach for xFe@NCs rational design, and deepen the understanding of FeNx activation mechanism of PDS in carbon nanomaterials.