Single-atom co sites confined in layered double hydroxide for selective generation of surface-bound radicals via peroxymonosulfate activation

Selective production of specific radical species with prolonged lifetime is challenging in advanced oxidation process. Herein, we constructed single-atom Co (SA-Co) catalytic sites confined in layered double hydroxide (LDH) for selectively and sustainably generate radical species via peroxymonosulfate (PMS) activation. The negatively charged PMS was stabilized by the positively charged LDH and simultaneously activated by the nanoconfined Co single-atom sites, resulting in oriented-production of surface-bonded •OH and SO4•− radicals with long-term efficiency (up to 48 h), suppressed PMS decomposition and radical self-quenching. Ion competition experiments and in-situ spectroscopic studies were applied to monitor the PMS activation processes. The SA-Co-LDH/PMS system outperforms the benchmark homogeneous (Co2+/PMS) and heterogeneous (Co3O4/PMS) catalytic systems for the degradation of emerging organic contaminants (EOCs) with the lowest Co consumption and highest catalytic efficiency.