Nanoscale Engineering of Cobalt Corrole-MWCNT Nanoconjugates: Substituent-Driven Selectivity for Sustainable Electrosynthesis of Hydrogen Peroxide

To efficiently produce H 2 O 2 through the two-electron reduction of oxygen, we have developed a low-cost, nanoscale electrocatalyst composed of nanoconjugates formed between multiwalled carbon nanotubes (MWCNTs) and three cobalt corroles with varying substituents: nonfunctionalized (Co1), hydroxyl-functionalized (−OH, Co2), and carboxyl-functionalized (−COOH, Co3). These cobalt corrole–MWCNT nanoconjugates, synthesized via noncovalent π-π interactions, are denoted as Co1@MWCNT, Co2@MWCNT, and Co3@MWCNT, respectively. The nanostructured morphology and uniform dispersion of the corrole species on the MWCNT surface are critical to their performance and are thoroughly analyzed by various techniques. Electrochemical evaluation reveals that these nanoconjugates promote the selective two-electron oxygen reduction, enabling efficient HO 2 – production. Among the three nanoconjugates, Co2@MWCNT exhibits the highest efficiency, achieving a HO 2 – yield of 81%. Its superior nanoscale interface and electron transport characteristics also contribute to enhanced durability and operational stability in alkaline media. These features make Co2@MWCNT a highly promising nanocatalyst for practical and scalable H 2 O 2 electrosynthesis. Additionally, in-depth electrochemical studies provide insight into the reaction kinetics, long-term durability, and potential for scale-up, reinforcing the importance of nanoscale design in advancing green electrosynthesis technologies.