Rational modulation of Fe single-atom electronic structure in a Fe-N2B4 configuration for preferential 1O2 generation in Fenton-like reactions

The important role of optimizing the coordination environment of single-atom catalysts (SACs) for selective production of singlet oxygen (¹O₂) in Fenton-like reactions is revealed. Herein, we introduce electron-depletion boron atoms to manipulate the coordination number and atom types of Fe site simultaneously and construct a six-coordination Fe-N₂B₄ catalyst for peroxymonosulfte (PMS) activation. Particularly, it achieves 98.68% ¹O₂ generation selectivity superior to unregulated Fe-N₄ catalyst (64.57%), exhibiting an exceptional bisphenol A (BPA) degradation performance with a reaction rate constant of 0.249 min⁻¹. Experimental and theoretical results unveil that the tailored electronic structure of Fe not only enhances the adsorption selectivity of terminal oxygen atoms in PMS and alters the reaction pathway preference, but also facilitates the electron donation from PMS and lowers the energy barrier for ¹O₂ generation. This work provides a universal strategy for rational and precise modulation of SACs for specific reactive species conversion in environment remediation.