Regulating the Local Electronic Structure of Copper Single Atoms with Unsaturated B,O-Coordination for Selective ¹O₂ Generation

Generating singlet oxygen (1O2) on single atom catalysts (SACs) in peroxymonosulfate (PMS)-based Fenton-like reactions exhibits great potential for selective degradation of contaminants in complex wastewater. Clarifying the structure–activity relationship between the electronic structure of SACs and the 1O2 generation selectivity is crucial for the precise design of efficient Fenton-like catalysts, but it is challenging. Herein, the generation selectivity of 1O2 on Cu SACs with different electronic structures (namely, Cu–O2X, where X = N, S, B, P, and O) is investigated by density functional theory calculations using the adsorption selectivity of terminal oxygen atoms in PMS as an activity descriptor. Significantly, the selectivity of 1O2 generation is affected by the electronic structure of the Cu center in which the electron-depleted Cu-O2B site exhibits a higher selectivity for the adsorption of terminal oxygen atoms. Experimentally, the Cu-O2B moiety exhibits superior catalytic activity for PMS activation, showing nearly 100% selectivity for 1O2 generation and a ciprofloxacin degradation rate of 0.2250 min–1, outperforming those of the other counterparts. The high catalytic activity is attributed to the asymmetric Cu-O2B site accelerating faster electron transfer and O–O bond stretching, lowering the energy barrier of key intermediates toward 1O2 generation. This work provides a broader perspective for regulating the electronic structure of single Cu sites at the atomic level and for the precise design of efficient Fenton-like catalysts.