CoN₁ O₂ Single-Atom Catalyst for Efficient Peroxymonosulfate Activation and Selective Cobalt(IV)=O Generation

Area of Science:

• Environmental Chemistry
• Catalysis
• Materials Science

Background:

• High-valent metal-oxo (HVMO) species are effective in advanced oxidation processes (AOPs) for degrading persistent water pollutants.
• Generating high-valent cobalt-oxo (CoIV=O) species is challenging due to cobalt's electronic configuration, hindering peroxymonosulfate (PMS) activation.

Purpose of the Study:

• To develop a strategy for enhancing CoIV=O generation using isolated cobalt sites with a specific N1O2 coordination on Mn3O4.
• To investigate the catalytic activity of the engineered CoN1O2/Mn3O4 for PMS activation and sulfamethoxazole (SMX) degradation.

Main Methods:

• Synthesis of isolated Co sites with N1O2 coordination on Mn3O4.
• Evaluation of PMS activation and SMX degradation using the synthesized catalyst.
• Comparison of catalytic performance against CoO3, CoN4, and commercial cobalt oxides.

Main Results:

• The asymmetric N1O2 configuration promotes PMS adsorption, dissociation, and CoIV=O generation by facilitating electronic delocalization at Co sites.
• CoN1O2/Mn3O4 exhibited significantly higher activity in PMS activation and SMX degradation compared to control catalysts.
• CoIV=O species were confirmed to oxidize SMX via oxygen atom transfer, producing less toxic byproducts.

Conclusions:

• The N1O2 coordination strategy effectively overcomes the challenge of CoIV=O generation, leading to highly active environmental catalysts.
• This work provides molecular-level insights into PMS activation mechanisms and guides the design of novel catalysts for water remediation.