Efficient persulfate non-radical activation of electron-rich copper active sites induced by oxygen on graphitic carbon nitride

Highlights: • A Cu and O co-doped g-C₃N₄ efficient non-radical catalyst was prepared. • The synergistic relationship between Cu and O was revealed, Cu as a rich electronics center. • BPA was degraded efficiently through ¹O₂ and mediated electron transfer. • The non-radical degradation process of BPA was revealed. Peroxymonosulfate (PMS) non-radical reactions possess high catalytic activity for specific pollutants under complex water environments. However, the synthesis of high-performance catalysts and the discussion of non-radical reaction mechanisms are still unsatisfactory. Here, a novel and efficient non-radical catalyst (O-CuCN) was successfully assembled using the scheme of Copper (Cu) and oxygen (O) co-doping. The O element with great electronegativity induces graphite carbon nitride (g-C₃N₄) to act as a medium to change the phase properties and electron density distribution of g-C₃N_4, and provides a support for the targeting of Cu. Cu is introduced into g-C₃N₄ as an active site in the phase structure, and an electron-rich center with the Cu site is formed, which forms a metastable intermediate after the adsorption of PMS by Cu as the active site. The new catalyst O-CuCN has outstanding activity in the PMS system, and its degradation rate for bisphenol A (BPA) is increased by more than 20 times compared to that of g-C₃N₄, and it has excellent environmental tolerance and stability. This work demonstrates that the formation of metastable intermediates and the initiation of effective non-radical reactions can be achieved by constructing differentiated electron density structures.