Precise manipulation of iron spin states in single-atom catalytic membranes for singlet oxygen selective production

Abstract

Heterogeneous single-atom catalysts are attracting substantial attention for selectively generating singlet oxygen (¹O2). However, precise manipulation of atom coordination structures remains challenging. Here, the fine coordination structure of iron single-atom carbon-nitride catalysts (Fe-CNs) was manipulated by precisely tuning the heating rate with 1 °C min⁻¹ difference. Multiple techniques in combination with density functional theory (DFT) calculations reveal that FeN6 coordination sites with high Fe spin states promote the adsorption, electron transfer, and dissociation of peroxymonosulfate (PMS), resulting in nearly 100% selection of ¹O2 generation. A lamellar single atom catalytic membrane is constructed, exhibiting high permeance, high degradation, high-salinity resistance and sustained operation stability. This work provides ideas for regulating spin states of the metal site to fabricate catalysts with selective ¹O2 generation for membrane separation and environment catalysis applications.