The interaction of surface electron distribution-polarized Fe/polyimide hybrid nanosheets with organic pollutants driving a sustainable Fenton-like process

Abstract

Many organic pollutants are rich in electrons, which are not used in the current pollutant removal technology, resulting in high energy consumption and low efficiency. To achieve a sustainable conversion of pollutants using Fenton-like technology, surface electron distribution-polarized lotus flower-like Fe-doped polyimide hybrid nanosheets (lf-Fe/PI HNs), a Fenton-like catalyst, are first developed for electron transfer and storage between pollutants and H₂O₂. Fe²⁺/Fe³⁺ ions are found in the framework of lf-Fe/PI HNs and directly bond with the C and N species of polyimide to form C–Fe–N–C in a closed loop. The experimental results and theoretical calculations demonstrate that electron-rich Fe and electron-deficient C areas are produced in the C–Fe–N–C of lf-Fe/PI HNs. This novel structure type in Fe-based materials leads to an excellent Fenton-like catalytic performance and efficiency for the refractory pollutant degradation under neutral conditions. The reaction rate is found to be 7–10 times higher than that of the conventional Fe-based Fenton-like catalyst. The reaction mechanism revealed that H₂O₂ is reduced to ˙OH radicals (further attacking pollutants) in the electron-rich Fe areas, and pollutants are mainly oxidized and degraded by providing electrons for the electron-deficient C areas. Fe–N–C acts as a bridge for electron transfer and electron storage carriers between pollutants and H₂O₂. This process enables the sustainable use of the electrons of pollutants, thereby greatly reducing the energy consumption for water treatment.