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.

In this study, a novel 2-vinylpyridine functionalized magnetic nanoparticle (Mag-PVP) was successfully prepared. The prepared Mag-PVP was characterized by transmission electronic microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA), and was used for the adsorption of bisphenol A (BPA) from aqueous solutions. Mag-PVP, which is composed of Fe₃O₄ nanoparticles and poly divinylbenzene-2-vinylpyridine (with a thickness of 10 nm), exhibited magnetic properties (M_s = 44.6 emu/g) and thermal stability. The maximum adsorption capacity (Q_m) of Mag-PVP for BPA obtained from the Langmuir isotherm was 115.87 mg/g at 20 °C, which was more than that of Fe₃O₄ nanospheres. In the presence of NaCl, the improved adsorption capacity of Mag-PVP was probably attributed to the screening effect of Mag-PVP surface charge and salting-out effect. In the presence of CaCl₂ and humic acid (HA), the adsorption capacity of BPA decreased due to competitive adsorption. The adsorption of BPA by Mag-PVP increased slightly with the increase in pH from 3.0 to 5.0 and obtained the largest adsorption amount at pH 5.0, which was probably attributed to hydrogen bonding interactions. Moreover, in actual water, Mag-PVP still showed excellent adsorption performance in removing BPA. The high adsorption capacity and excellent reusability performance in this work indicated that Mag-PVP was an effective adsorbent for removing BPA from aqueous solutions.