@article {ZONG2022120722, title = {High-valent cobalt-oxo species triggers hydroxyl radical for collaborative environmental decontamination}, journal = {Applied Catalysis B: Environmental}, volume = {300}, year = {2022}, pages = {120722}, abstract = {The overlooked role of high-valent cobalt-oxo species (Co(IV)) in the Co(II)/peroxymonosulfate (PMS) process was uncovered recently using methyl phenyl sulfoxide (PMSO) as the probe. Herein, we further interestingly found that Co(IV) could trigger hydroxyl radical ({\textbullet}OH) formation, resulting in the oxidized products distribution of PMSO heavily relied on the relative concentration of PMSO. More significantly, the generation of a series of 18O-labeled hydroxylated products (i.e., hydroxylated methyl phenyl sulfone, nitrobenzene and 4-nitrobenzoic acid) in H218O conclusively verified that {\textbullet}OH was triggered by Co(IV) species. Density functional theory calculation demonstrated that Co(IV) initiated {\textbullet}OH formation via oxo ligand protonation-induced valence tautomerization. Moreover, the oxidative contribution of Co(IV) and {\textbullet}OH on organic degradation was specifically dependent on the type and concentration of the substrate. This study provided deeper insights into the evolution pathway of {\textbullet}OH mediated by Co(IV) species and enriched the understandings on the collaborative oxidation mechanism in Co(IV)-involved processes.}, keywords = {High-valent cobalt-oxo species, Hydroxyl radical, O-isotope labeling, Substrate and concentration-dependent oxidation}, issn = {0926-3373}, doi = {http://doi.org/10.1016/j.apcatb.2021.120722}, url = {http://www.sciencedirect.com/science/article/pii/S092633732100847X}, author = {Zong, Yang and Hua Zhang and Xiaomeng Zhang and Liu, Wen and Xu, Longqian and Wu, Deli} }