Ultrafast activation of peroxymonosulfate by single atom cobalt anchored on N-doped two-dimensional Ti3C2Tx MXene for organic pollutant degradation

Supported single-atom catalysts (SACs) have attracted great attention for organic pollutant degradation due to their exceptional catalytic activity and atomic utilization. In this work, we synthesized single Co atoms anchored on nitrogen-doped Ti 3 C 2 T x MXene (Co-N-Ti 3 C 2 T x ), leveraging its unique layered structure to create a nanoscale confinement environment that enhances catalytic performance. This spatial confinement, synergistically combined with nitrogen-induced electronic modulation, significantly promotes peroxymonosulfate (PMS) activation and accelerates electron transfer, resulting in ultrafast degradation of enrofloxacin (ENR). The Co-N-Ti 3 C 2 T x /PMS system exhibits catalytic activity 2.4 times higher than pristine Co-Ti 3 C 2 T x and outperforms previously reported catalysts for PMS-driven ENR removal. The quenching experiments, electron spin resonance (EPR) detection and electrochemical studies demonstrated that SO 4 •− and 1 O 2 are two main reactive species with electron transfer as the dominant reaction. First-principle calculations indicate that the introduction of N can enhance the PMS adsorption and promote the enrichment and supply of electrons to produce reactive species. Further, this catalyst also demonstrates outstanding durability after multiple cycles toward various organic pollutants. This study highlights the critical role of nanoscale confinement coupled with electronic tuning in single-atom catalysis, providing valuable insights for designing high-performance advanced oxidation systems to water purification. • Synergistic confinement and N modulation accelerate interfacial electron transfer. • Nitrogen doping enhances PMS adsorption and 1 O 2 reactive species generation. • Co-N-Ti 3 C 2 T x /PMS exhibits catalytic activity 2.4 times higher than Co-Ti 3 C 2 T x . • Outstanding durability after multiple cycles toward various organic pollutants