Modulating the electronic structures of Fe3C-based catalyst by surface sulfidation to facilitate H2O2 activation

The performance of Fe-based heterogeneous Fenton catalysts is apparently affected by the electron density of Fe active site. Herein, we modulate the active site electronic density of the Fe3C-based catalyst by surface sulfidation to improve H2O2 activation property. After sulfidation, the removal of acetaminophen (APAP) increased from 27.1% to 100%, and the degradation rate constant k(obs) of APAP increased 5.44-fold. Sulfidation enhances the utilization of H2O2 and improves the generation of active species. Theoretical calculations demonstrated that sulfidation increases the electron density of Fe sites and lowers the band gap between the d-band center and Fermi energy level, facilitating electron transfer and H2O2 activation. The change in cleavage position of H2O2 from O-H to O-O after sulfidation provides additional evidence for the increased generation of center dot OH. These results elucidate the promoting effect of sulfidation on heterogeneous Fenton catalysts and provide a strategy for improving the performance of catalyst and contaminant removal.