Spin-state regulated CoCe dual-atom catalyst triggers efficient 1 O 2 production for water cleanup

Abstract

Spin-state engineering of atomic active sites is pivotal in selective singlet oxygen ( 1 O2) generation during Fenton-like catalysis.Dual-atom catalysts (DACs) offer flexibility in spin-state regulation, while precisely regulating spin state remains challenging. Here, CoCe dual-atom catalyst (CoCe-N/C) with moderate spin state was designed for efficient 1 O2 generation in peroxymonosulfate (PMS) activation. The incorporation of Ce adjacent to Co-N4 moieties distorted the symmetry of ligand field and reduced the crystal field splitting energy (Δ), thus inducing spin crossover of Co configuration from low-spin state (LS Co 3+ : t2g 6 eg 0 ) to medium-spin state (MS Co 3+ : t2g 5 eg 1 ). The MS electron configurations of CoCe-N/C facilitated the orbital overlap with PMS and significantly reduced 1 O2 generation barrier, resulting in RhB elimination kinetics 12.3 times higher than that of Co-N/C. Simultaneously, the electron buffer of neighbouring Ce enabled to stabilize and expedite the conversion of Co 3+ /Co 2+ via Ce 4+ /Ce 3+ cycling, achieving strong anti-interference and dynamic-degradation capability in continuous-flow filtration systems for water purification. This work presents a novel strategy for spin-state modulation of DACs in 1 O2-based Fenton-like reactions.