Targeted construction of high-valent metal-oxo species: From multi-scale design to environmental applications

High-valent metal-oxo species (HVMOs) from single-atom catalysts (SACs) offer selective oxidation and strong interference resistance for treating complex organic pollutants, yet a unified framework linking SACs structure to HVMOs formation and performance is lacking. This review systematically summarizes research progress on regulating HVMOs generation through multi-scale engineering strategies and on their application in environmental catalysis. Firstly, a comprehensive regulatory framework linking structural design, electronic modulation and reaction pathways has been established across atomicscale (first-shell coordination, distal coordination, and dual-atom site cooperative), nanoscale (space confinement and local electric field effect) and macroscale (carbon-based, porous, and metal oxide supports) dimensions, which elucidates the mechanisms of action for multi-level strategies in enhancing the selectivity and efficiency of HVMOs generation. Furthermore, the structure-function relationship between the electronic structural characteristics of HVMOs and their oxidation behavior is elucidated. A systematic review of HVMOs identification and mechanism validation is presented by integrating chemical probes, isotope labelling, and in situ spectroscopic techniques. The application progress of HVMOs in the mineralization and polymerization of organic pollutants is introduced. Ultimately, key challenges and opportunities in dynamic mechanisms, practical application, and resource conversion are discussed, offering guidance for precise catalytic water treatment.