Morphology-coordination dual engineering in cobalt single-atom catalysts: Steering peroxymonosulfate activation into selective 1O2 generation for efficient antibiotic degradation

Remediation of antibiotic-contaminated water demands advanced oxidation processes with efficient singlet oxygen ( 1 O 2 ) generation. Conventional catalysts, however, suffer from limited active sites and sluggish radical production. Herein, a self-assembly tethering strategy is innovatively developed to precisely and simultaneously regulate the hollow tubular morphology and atomic coordination structure of cobalt single atoms anchored on boron-doped carbon nitride (CN). This yields a Co-N 3 B 1 catalyst for peroxymonosulfate (PMS) activation. Morphological reconstruction from bulk to hollow tubular CN exposes abundant active sites for PMS adsorption, while coordination engineering tailors the Co-N 3 B 1 configuration. Boron doping induces electron redistribution via p-d orbital hybridization, creating dual adsorption sites and optimizing PMS activation. The optimized Co-N 3 B 1 exhibited excellent catalytic performance for tetracycline hydrochloride degradation with a rate constant of 1.337 min −1 and a high 1 O 2 selective generation of 98.55 %. Combined experimental and theoretical studies reveal that the tailored Co electronic structure lowers the adsorption energy of PMS, enhances electrons donation of PMS, and reduces the energy barrier for 1 O 2 formation from *O intermediates (2.3–2.09 eV), facilitating O−O bond cleavage. Additionally, the doped B 2p orbitals effectively accept Co 3d electrons, thus weakening the Co−O bond between Co and PMS, enabling highly selective generation of 1 O 2 . This work provides a universal strategy for rational and precise modulation of specific reactive species in environmental remediation.