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

Generating singlet oxygen (O-1(2)) 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 structureactivity relationship between the electronic structure of SACs and the O-1(2) generation selectivity is crucial for the precise design of efficient Fenton-like catalysts, but it is challenging. Herein, the generation selectivity of O-1(2) 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 O-1(2) 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 O-1(2) 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 O-1(2) 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.