Rational regulation of the electronic structure of Cu₁ sites catalyst to modulate persulphate activation pathway

Single-atom CuN4 catalyst have demonstrated excellent efficiency by producing 100 % singlet oxygen (1O2) in persulfate activation system. However, 1O2-based nonradical system may not provide satisfying efficiency in refractory organic pollutants removal. Herein, we report that the bottleneck can be well tackled by refining the peroxydisulfate activation pathway in advanced oxidation processes (AOPs) via manipulating the electron structure of the catalysts. As expected, the resulting Cu-N3O with optimized electronic structure can efficiently activate peroxydisulfate (PDS) from non-radical to radical-nonradical coexist during PDS activation process, exhibiting highest normalized Kper-site value, which was up to 1.474 x 104 min-1mol-1. Both experimental and theoretical results demonstrate that the electron-rich oxygen (O) can result in more unoccupied orbitals and upshift the d-band center, and thereby optimizes the PDS adsorption energy by producing multiple reactive oxygen species for BPA removal. This work provided a potential approach for the coordination environment modulation of SSCs to regulate persulphate activation pathway in environmental remediation.