Nitrogen vacancy-induced d-band center upshift in Co4N-600 nanozyme breaks the oxygen wall and facilitates CoIV=O formation for emerging contaminants degradation

Nitrogen vacancy incorporation into Co 4 N-600 upshifts the D-band center and facilitates the generation of Co IV =O. • The Co 4 N-600/PMS system yields a modified kinetic rate constant of 300.6 min⁻ 1 M⁻ 1 . • Rapid degradation of different types of pollutants within Co 4 N-600/PMS system. High‑valent cobalt-oxo species (Co IV =O) have been demonstrated to exhibit efficient degradation capability toward emerging contaminants (ECs). However, the 3d 7 electronic configuration of Co(II) sites in Co‑based catalysts severely restricts their binding affinity to the terminal oxygen of peroxymonosulfate (PMS), which is unfavorable for the generation of Co IV =O. Herein, we report a nitrogen vacancy (Nv)‑rich cobalt nitride nanozyme Co 4 N-600. The introduction of Nv markedly reduces the d‑electron occupancy of Co, upshifts the d‑band center, and promotes the formation efficiency of Co IV =O. Remarkably, employing 150 mg L −1 peroxymonosulfate (PMS) as the oxidant, the Co 4 N-600 nanozyme achieves complete degradation of 10 mg L −1 imidacloprid within 10 min at an ultralow catalyst loading of 1 mg L −1 , yielding an excellent modified kinetic rate constant of 300.6 min −1 M −1 . These findings establish d -band center engineering as an effective strategy for boosting the catalytic performance of nanozymes by promoting the generation of high-valent metal-oxo (HVMO) species. Download: Download high-res image (179KB) Download: Download full-size image