Oxygen vacancy modulation of single atom cobalt-activated peroxymonosulfate for highly selective generation of singlet oxygen and effective degradation of organic pollutants in actual water bodies

Abstract

Singlet oxygen (¹O₂) is an excellent reactive species with solid resistance to refractory pollutants, and it is critical to enhancing the generation of ¹O₂ in the persulfate system. In this work, we developed a vacancy-containing copper oxide supported Co single atom catalyst (Co_SACs/CuO(O_v)) containing abundant cobalt active sites for the activation of PMS to achieve efficient ¹O₂ selective generation, thereby exhibiting ultra-high ciprofloxacin removal efficiency. Density functional theory calculations revealed that Co_SACs/CuO(O_v) adsorbed the single O atom from the SO₄ side chain of PMS, facilitating its oxidation into *OH and subsequent efficient production of ¹O₂. The Co_SACs/CuO(O_v)/PMS system exhibited strong resistance to variations in pH and coexisting substances in water, and the toxicity of CIP was significantly reduced after treatment. Furthermore, when the Co_SACs/CuO(O_v) catalyst was immobilized on the PTFE filter membrane, it maintained the CIP removal efficiency above 75 % for 20 h under low temperatures (0℃) and in various complex aqueous environments. This work provides new insights into the design of catalysts featuring single-atom active sites and high-efficiency ¹O₂ generation, which is essential for potential applications in water purification.