Design of a highly active defect-site Mo/Cu interface catalyst on a carbon fibre support and its degradation of high-concentration tetracycline: dissociation mechanisms of PMS and optimisation of electronic transitions

Background Atomic-scale defects derived from bimetallic heterojunctions significantly promote the active dissociation of peroxymonosulfate (PMS). Given the challenge of degrading emerging pollutants in aquatic environments, investigating efficient PMS activation technologies and the mechanisms underlying the decomposition of high-concentration tetracycline (TC) is crucial for the development of highly efficient catalysts. Methods CC@MoS₂-CuO was prepared by orderly anchoring MoS₂ and CuO nanoparticles onto carbon fabric. Characterizations: EXAFS, XANES, TEM, XRD, SEM, EDS, TGA, FTIR, BET, XPS, EPR. Degradation of 40 ppm TC was tested under optimized conditions (3 × 1 cm × 1 cm catalyst, 1 mM PMS, pH 9.0, 298 K). Intermediates/toxicity were identified by LC-MS and T.E.S.T.; the extent of mineralization was evaluated by TOC. Significant findings The system achieved 100% TC removal (k = 0.11435 min⁻ 1 ) under the optimized conditions of pH 9.0, 40 mg/L TC, 3 × 1 cm × 1 cm catalyst, and 1.0 mM PMS at 298 K. Synchrotron and DFT calculations showed that the synergistic effect at the Mo/Cu interface, along with the presence of defect-related structures, was associated with a lowered PMS dissociation barrier, which may facilitate ROS generation. Quenching experiments confirmed a ·OH-dominated process. Intermediate pathways were identified, indicating manageable ecological risks. This work supports the design of simple, split-type bimetallic defect catalysts for sustainable water treatment.