CoN₁O₂ Single‐Atom Catalyst for Efficient Peroxymonosulfate Activation and Selective Cobalt(IV)=O Generation

Abstract

High‐valent metal‐oxo (HVMO) species are powerful non‐radical reactive species that enhance advanced oxidation processes (AOPs) due to their long half‐lives and high selectivity towards recalcitrant water pollutants with electron‐donating groups. However, high‐valent cobalt‐oxo (CoIV=O) generation is challenging in peroxymonosulfate (PMS)‐based AOPs because the high 3d‐orbital occupancy of cobalt would disfavor its binding with a terminal oxygen ligand. Herein, we propose a strategy to construct isolated Co sites with unique N1O2 coordination on the Mn3O4 surface. The asymmetric N1O2 configuration is able to accept electrons from the Co 3d‐orbital, resulting in significant electronic delocalization at Co sites for promoted PMS adsorption, dissociation and subsequent generation of CoIV=O species. CoN1O2/Mn3O4 exhibits high intrinsic activity in PMS activation and sulfamethoxazole (SMX) degradation, highly outperforming its counterpart with a CoO3 configuration, carbon‐based single‐atom catalysts with CoN4 configuration, and commercial cobalt oxides. CoIV=O species effectively oxidize the target contaminants via oxygen atom transfer to produce low‐toxicity intermediates. These findings could advance the mechanistic understanding of PMS activation at the molecular level and guide the rational design of efficient environmental catalysts.

Constructing Hollow Multishelled Microreactors with a Nanoconfined Microenvironment for Ofloxacin Degradation through Peroxymonosulfate Activation: Evolution of High-Valence Cobalt-Oxo Species

“…During PMS activation, the emerging Raman peak at 571 cm −1 was attributed to Co(IV)�O. 53 Thus, the presence of Co(IV)�O in the TS-Co/HM−PMS system was confirmed. In addition, methyl phenyl sulfone (PMSO 2 ), a sulfone product, could be generated only after O transfer between PMSO and Co(IV)�O.…”

Atomically Dispersed N/O-Coordinated Cobalt Catalyst Enables Aerobic Oxygenation of Olefins under Ambient Conditions

“…Importantly, the Co K edge position of Co 1 /NOC appeared in a higher energy region than that for Co 1 /NC, implying that the Co atom in Co 1 /NOC is more positively charged than that of Co 1 /NC (Figure c). These differences suggest that O-coordination has a stronger electron-withdrawing ability than N-coordination with Co. ,,, …”

“…Importantly, the Co K edge position of Co 1 /NOC appeared in a higher energy region than that for Co 1 /NC, implying that the Co atom in Co 1 /NOC is more positively charged than that of Co 1 /NC (Figure 2c). These differences suggest that O-coordination has a stronger electron-withdrawing ability than N-coordination with Co. 30,40,42,43 The Fourier-transformed EXAFS spectrum of Co 1 /NOC showed a prominent peak at 1.50 Å (Figure 2d (Figure S8d), indicating that they can be attributed to the contribution from backscattering between Co and light atoms. In addition, the intensity maximum of Co foil appears at 6.95 Å −1 , 2.20 Å (Figure S8c), which is not observed in the Co 1 / NOC and Co 1 /NC (Figure S8a,b).…”

Continuous On-Site H2O2 Electrosynthesis via Two-Electron Oxygen Reduction Enabled by an Oxygen-Doped Single-Cobalt Atom Catalyst with Nitrogen Coordination

“…Carbon-supported Co SACs were thought to be efficient 2e – ORR catalytic sites, when being coordinated with nitrogen or oxygen coordination. ,,,, Inspired by successfully implanting atomic dispersion cobalt on carbon nitride and metal oxide supports using cobalt acetylacetonate precursors, − a facile thermal decomposition of Vulcan XC-72 CB in the presence of Co­(acac) 2 and urea is proposed for synthesizing the Co-N/O-C. The synthetic process is schematically shown in Figure S5.…”