Enhanced H2O2 production using 4,4′-diaminoazobenzene-, and 2-hydroxy-1,4-naphthoquinone-modified carbon as a gas diffusion electrode

Author

J. Lee, M. Park, H. J. Lee, K. M. Lee, C. Lee.

Journal

J. Electroanal. Chem.

Issue / Vol

vol. 1000, p. 119650

Date

(2026.01.01)

Year

2026

Carbonaceous electrodes demonstrate high selectivity for the two-electron oxygen reduction reaction (2e−ORR) and are cost-effective and scalable. Although capable of producing high concentrations of hydrogen peroxide (H₂O₂), their considerable electrode resistance results in substantial energy consumption. This study aims to enhance the 2e−ORR activity of pristine carbon by modifying carbon black (CB) surfaces with 4,4′-diaminoazobenzene (DAAB) and 2-hydroxy-1,4-naphthoquinone (HNQ)—organic molecules that incorporate azo and quinone groups, respectively—and integrating these into gas diffusion electrodes (GDEs). In undivided cells, DAAB/CB and HNQ/CB GDEs displayed Faradaic efficiencies (F.E.s) that were 1.26–1.85 and 1.14–1.75 times higher, respectively, than those of the unmodified CB GDE. Notably, the 0.5 wt% DAAB/CB and 4.0 wt% HNQ/CB GDEs consistently showed the highest F.E.s, surpassing those of other carbonaceous materials such as g-C₃N₄ and CNT. Moreover, the energy consumption decreased by 43.92% with the 0.5 wt% DAAB/CB GDE and by 45.91% with the 4.0 wt% HNQ/CB GDE when compared to the pristine CB GDE. In addition, the cycling stability test in the undivided cell confirmed that the modified CB GDEs maintained superior H₂O₂ production performance compared to the pristine CB over 10 consecutive cycles, demonstrating their excellent durability and reusability. Electrochemical analysis confirmed that these organic modifications significantly enhance 2e−ORR and reduce side reactions. These results validate the efficiency and benefits of this straightforward organic modification approach in improving the electrosynthesis of H₂O₂.