Strategic combination of N-doped graphene and g-C3N4: Efficient catalytic peroxymonosulfate-based oxidation of organic pollutants by non-radical-dominated processes

In this study, two metal-free materials, i.e., N-doped graphene (rGO-N) and g-C3N4, were strategically combined to prepare a novel g-C3N4/rGO-N composite for activating peroxymonosulfate (PMS). The g-C3N4/rGO-N composite showed large specific surface area and high graphite-rich N content, and hence, exhibited excellent catalytic performance because of the synergistic effect of g-C3N4 and rGO-N. The oxidative system could effectively degrade various pollutants (e.g., acid orange 7, orange G, ciprofloxacin, and bisphenol A). The radical quenching experiments and electron paramagnetic resonance spectra analysis revealed that the novel carbonaceous composite could realize PMS-based non-radical oxidative degradation of pollutants unlike the previously reported catalysts, observed the degradation via a radical-dominated pathway. The real-time water treatment experiments demonstrated the potential of the oxidative system to environmental remediation applications. The combination strategy provides an innovative approach to fabricate binary metal-free carbonaceous catalysts for carrying out PMS-based non-radical oxidative degradation of pollutants.