Reactive oxygen species regulation and synergistic effect for effective water purification through Fenton-like catalysis on single-atom Cu–N sites

Abstract

The efficient production and synergistic effect of reactive oxygen species (ROS) are critical in the environmental, chemical and biological fields. Chemical production is suitable for a variety of scenarios and requires no additional equipment, but generates ROS with low efficiency and poor selectivity. In this study, we demonstrated a single-atom Cu–N structure with a unique oxidation state for efficient ROS production and synergistic water purification. The kinetic reaction rate of Cu-SA/H₂O₂ is 1.23 times higher than that of Fe²⁺/H₂O₂ under weakly acidic conditions. Through experiments and density functional theory (DFT) calculations, the Cu–N coordination structure exhibited different adsorption energies for H₂O₂, peroxydisulfate (PDS) and peroxymonosulfate (PMS), thus enabling highly selective production of different ROS from different catalytic pathways. Efficient and differentiated ROS production allows Cu-SA to be used for the compounding of multiple oxidants, so as to achieve ROS ratio regulation, thereby synergistically and efficiently removing pollutants (COD removal rate increased from 36.8% to 70.7%). Our results highlight single-atom catalyzed efficient ROS production and its synergistic effect for a wide range of potential applications, including environmental remediation.