Mechanical insight into direct singlet oxygen generation pathway: The significance of Co-O-X bond formation anchored by cobalt single atoms on mesoporous oxides

The understanding of how single atoms anchoring on oxides contribute to high-activity catalysis in the sulfate radical -advanced oxidation process (SR-AOP) remains obscure. Here we presented a new strategy for regulating singlet oxygen (1O2) generation in peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) by engineering the Co -O -X active sites on oxide supports in this study. The Co single atoms supported on mesoporous oxides (CoSA-XO2) were first successfully developed using a modified sol-gel solvent vaporization self-assembly method. We found that CoSA-XO2 catalysts served as efficient PMS activators for pollutant decomposition over a wide pH range. Notably, CoSA-TiO2 exhibited exceptional performance, achieving nearly 100% removal of sulfasalazine (SSZ) within 10 min. Furthermore, evidenced by experimental results and density functional theory (DFT) calculations,1O2 was confirmed to be predominately active oxidizing species by the unique Co -O -X bonds for activating PMS in CoSA-XO2/PMS system, resulting in an excellent pollution degradation. This study provides valuable insights into the construction of highly loaded single-atom catalysts using oxide substrates in the PMSAOP system, along with the mechanism of regulating reactive oxygen species (ROS) formation through interfacial bonding between active metal and support.