Electron-rich/poor reaction sites enable ultrafast confining Fenton-like processes in facet-engineered BiOI membranes for water purification

Heterogeneous Fenton-reaction accomplishes the destruction of pollutants via the oxidation of hydroxyl radicals during water purification. Herein, two facet-engineered (control of different exposed crystal planes) BiOI nanocatalysts (BI-001 and BI-110) as the dual-reaction-center catalysts were loaded on the polyvinylidene fluoride membrane, remarkably accelerating the occurrence of Fenton-reaction and leading to the enhanced degradation of the pollutants in complex water matrices. The degradation efficiency of paracetamol by BI-110 membrane (~96.0%) was significantly higher than that of BI-001 membrane (~26.1%) in catalytic activity. The electron paramagnetic resonance tests and theoretical calculations proved that BI-110 possesses more oxygen vacancies, which acts as the electron-rich sites to trigger the Fenton-reaction. Correspondingly, the pollutants were adsorbed on the electron-poor Bi3+ sites and donate electrons during the degradation process. This study provides a candidate strategy to break the limitations of Fenton reaction advanced oxidation processes for water purification using the tunable facet-engineered BiOI membrane. [Display omitted] •Facet-engineered BiOI membranes are first proposed for water purification.•Enhanced AOP kinetics is due to the spatial nanoconfinement effect.•Fenton-like processes are realized on the electron-rich/poor reaction sites.•BI-110 membrane/H2O2 showed excellent performance in complex water matrix.