Defect-engineered FeSe2_x@C with porous architecture for enhanced peroxymonosulfate-based advanced oxidation processes

A novel heterogeneous and porous FeSe2_x @C-5 with abundant Se vacancies (V-se) was facilely synthesized via one-step carbonization-selenization approach from Fe-MOFs (metal-organic frameworks) and firstly applied in activating peroxymonosulfate (PMS) for iohexol (IOH) removal, exhibiting extraordinary catalytic performance with superior stability and adaptability. The roles and functions of V-se in the reaction system are deeply elucidated. Strikingly, systematic characterization and theoretical calculations revealed that V-se can modulate the surface electronic structure and accelerate Fe3+/Fe2+ cycle, leading to the strengthened binding energy and accelerated charge deliver for PMS activation. Accordingly, Iohexol (15 mg/L) can be eliminated within 30 min in FeSe2_x @C-5/PMS system, with apparent reaction rate constant (k(app)) 23.7 times higher than that in FeSe2/ PMS system. This study not only contributes to a tutorial guideline for designing high-performance catalysts by virtue of structural control and V-se engineering, but also extends its potential application in low-strength wastewater treatment.

Automated summary

A novel heterogeneous and porous FeSe2_x @C-5 material with abundant Se vacancies (V-se) was synthesized and applied in activating peroxymonosulfate (PMS) for iohexol (IOH) removal. The V-se plays a crucial role in modulating the surface electronic structure and accelerating Fe3+/Fe2+ cycle, leading to enhanced PMS activation efficiency.