Activation of peroxymonosulfate by a CuCo-NC diatomic catalyst on N-doped graphene for selective generation of 1O2 towards efficient organic pollutant treatment

Singlet oxygen (1O2) is an excellent active species for the selective degradation of organic pollutants. However, it is difficult to achieve efficiently and highly selective 1O2 generation. Herein, we report a Cu-doped Co-rGO (CuCo-rGO) as a precursor to construct diatomic catalyst (CuCo-NC) with both single atomic (SA) Co and Cu sites. The CuCo-NC activated peroxymonosulfate (PMS) can generate singlet oxygen (1O2) with high efficiency, which shows efficient degradation of tetracycline (TC) under wide pH rage and ubiquitous anions (H2PO4-, HCO3-, NO3-, Cl-) conditions. Meanwhile, CuCo-NC/PMS system can nearly 100% degrade the persistent organic pollutant (atrazine). Compared with SA Cu and SA Co sites, density functional theory calculations (DFT) demonstrate that the Cu-doping can improve the Co 3d orbital bonding distribution and reduce the adsorption energy of PMS. The role and formation mechanism of 1O2 are also analyzed and discussed. This work reveals the synergistic mechanism of the CuCo diatomic active sites for selective activation of PMS and provides a new direction for the development of novel catalyst with production of 1O2.