Ti3C2 MXene promoted Fe3+/H2O2 fenton oxidation: Comparison of mechanisms under dark and visible light conditions

The performance and mechanisms of a titanium carbide (Ti3C2) MXene modified Fe3+/hydrogen peroxide (H2O2) system were compared in detail under dark and visible light conditions, with a new mechanism proposed for the reaction and reduction of MXene by Fe3+. Using Bisphenol A (BPA) as the target pollutant, the degradation of BPA by the Fe3+/H2O2 system was improved after adding MXene in the dark, and the degradation rate of BPA was ≥ 95 % within 12.5 min under visible light, six times higher than that in the dark. Fe2+ was ascertained to be the effective component responsible for H2O2 activation to produce ·OH. SEM, XPS, ICP, XRD, and FTIR spectroscopy, analyses show that MXene and Fe3+ form a complex, and then MXene reacts with Fe3+ by breaking the Ti-C bonding to accelerate the Fe3+/Fe2+ cycle. MXene uses photogenerated electrons to promote this reaction under visible light. In addition, quenching experiments and electron spin resonance spectroscopy results show that ·OH and O2•- are the main reactive oxygen species under visible light, while ·OH is the main active species in the dark. MXene thus effectively uses O2 to form O2•- under visible light and promotes the Fe3+/Fe2+ cycle. This study provides a theoretical basis for the combination of visible light catalysis and the advanced oxidation process of a Ti3C2 MXene.