Photochemically Induced Co-oxidation of Aqueous Manganese and Cobalt and the Formation of Cobalt-Incorporated Manganese Oxides

• DOI: 10.1021/acs.est.4c14332
• Publication Date: 2025-05-21T12:18:29Z
• Authors: Zhenwei Gao; Gwan Yeong Jung; Ping-I Chou; Olaf J. Borkiewicz; Matthew Newville; Rohan Mishra; Young-Shin Jun

Manganese (Mn) oxides, widely found in aquatic and terrestrial environments, play crucial roles natural ecosystems environmental processes. Previously, it was believed that naturally abundant Mn oxides originated through biotically mediated However, we have revealed the significance of photochemically induced abiotic oxidation Mn2+(aq) to Mn(IV) oxides. This study further elucidates co-oxidation aqueous Mn2+ cobalt (Co2+), which leads predominant formation Mn(IV)-Co(III) oxide nanosheets. Both pair distribution function analysis X-ray absorption spectra provide evidence Co2+ is mainly oxidized Co(III) within plane structure, where forms double-edge-sharing arrangements. Additionally, initial concentration greatly influences extent Co incorporation final Mn-Co states. Increased correlates with a higher oxygen vacancies structures, reduces their band gap significantly reactivity governing ability participate pollutant degradation redox transformations. advances our understanding mechanism Co-incorporated environment provides insights into occurrence applications