Conversion of vacancy defects in Fe-polyoxometalates@Ti3C2 MXene promotes broad-spectrum degradation of bisphenols

Bisphenols (BPs) are products of the chemical industry with a large release amount, and developing effective BP removal technologies is a priority for achieving sustainable environmental development. The novel oxygen vacancy (OV)-rich Fe-polyoxometalates@Ti3C2 MXene (Fe-POMs@Ti3C2 MXene, FPTM) nanocomposites were successfully developed on the basis of vacancy conversion. The O atoms in Fe-POMs occupied the Ti vacancy defects in Ti3C2 MXene and new OVs were formed on FPTM upon loading. Low-valent Ti species (Ti(II) and Ti(III)) have redox reactions with Fe-POM, and the cation oxidation state of W in Fe-POM was reduced through electron transfer, which led to the separation of oxygen ions that bonded with W and then formed OVs. The FPTM with lateral OVs (doubly-bonded oxygen) had the strongest peroxymonosulfate (PMS) binding and electron transport ability, with binding energies of −10.2169 eV. FPTM achieved 82 %–100 % degradation of fourteen BPs into largely harmless products by generating reactive oxygen species (ROS) through electron transfer. FPTM also showed excellent repeatability and practical application. The differences in the extent of degradation of BPs can be explained by the molecular surface charge distributions. There were differences in the types and concentrations of ROS mediated by Ti vacancies and OVs, as well as the products and pathways of BPA. This work provides a new approach for defect engineering of MXene-based catalysts; the proposed approach considerably enhances the advanced purification of BP-polluted water and provides a new technique for broad-spectrum contaminant removal.