Dual action of non-metal doped C2N and Ti3C2T2 heterojunction enhances the catalytic activity of electrochemical simultaneous oxidation of hydrogen peroxide and peroxymonosulfate:A theoretical study

Electrochemical advanced oxidation processes (EAOPs) are energy-efficient methods for generating activated radicals like HO center dot and SO4 center dot-, which enable the degradation of difficult-to-mineralize chlorinated organic compounds. This study explored the catalytic activity and reaction mechanism of EAOPs under a dual strategy involving non-metal doped C2N (X@C2N (X = O, F, Si)) and a heterostructured build (X@C2N/Ti3C2T2) using first principles calculation. The non-metal doping and the heterojunction construction can make H2O2 and PMS spontaneously adsorb (E-ads < 0), with negative Gibbs free energy for their oxidation to HO center dot and SO4 center dot-, significantly enhancing catalytic activity. The catalytic activity of the X@C2N catalysts was in the order of O@, F@, and Si@C2N. The loading of Ti3C2T2 improved the stability and activity of the material, while Ti3C2F2 and Ti3C2O2 proved superior as heterojunction carriers compared to Ti3C2(OH)(2). Notably, O@C2N/Ti3C2F2 is proved to be an appropriate catalyst for simultaneous hydrogen peroxide (Delta G(max) = -0.90 eV) and peroxymonosulfate (Delta G(max) = -0.99 eV) oxidation reactions, achieving non-selective generation of oxidants in electrochemistry. 2,4-D can be effectively degraded by surface-generated HO center dot and SO4 center dot-, with the reactivity of SO4 center dot- towards 2,4-D greater than that of HO center dot. This research highlights the potential of combining heteroatom doping with heterojunction catalyst formation to enhance EAOPs for environmental remediation.