Boosting oxygen storage capacity of Fe-Cu bimetallic catalysts through sulfide modification for efficient and selective molecular oxygen activation

Molecular oxygen (O 2 ), a reactive oxygen species precursor, has great potential for water purification, but its spin-forbidden resistance hinders its direct involvement in the redox reactions of organic compounds under mild ambient conditions. In this study, a facile strategy was employed to synthesize sulfide-modified Fe-Cu bimetallic catalysts (FeCu-S) to enhance the activation efficiency of O 2 . The results showed that the FeCu-S material exhibited a tenfold increase in O 2 activation compared to that of the control group, primarily attributed to the increased specific surface area of the catalysts with an optimized Fe/Cu site distribution and promoted generation of Cu-containing crystalline phases (e. g., CuFeS 2 and CuO) to significantly enhanced the oxygen storage capacity. Moreover, such Cu-containing crystalline phases strengthened surface electron transfer, thus remarkably promoting the selective generation of singlet oxygen ( 1 O 2 ) for sulfamethoxazole (SMX) degradation. The FeCu-S/O 2 system maintained high activity after the fifth recycle with stable reaction pH and negligible leaching of Cu and Fe ions, also exhibited great performance in the advanced treatment of the real biological effluent and ultrafiltration effluent from landfill leachate, confirming its great potential for practical water purification applications.