Self-powered hydrogen peroxide electrosynthesis via zinc-air batteries with Co/N co-doped carbon nanofiber electrocatalyst

The synthesis of hydrogen peroxide (H₂O₂) via the two-electron oxygen reduction reaction (2e⁻ ORR) is a promising alternative to the conventional anthraquinone process. Herein, we report an integrated system for catalyzing the oxygen reduction reaction (ORR) in zinc-air batteries (ZABs) using a Co/N co-doped carbon nanofiber electrocatalyst (CoNC@CNF-900/OPT) fabricated via electrospinning. The optimized CoNC@CNF-900/OPT achieved a half-wave potential (E_1/2) of 0.786 V and an H₂O₂ selectivity of 62.5 % at 0.3 V vs. RHE. In an H-type electrolytic cell, the catalyst exhibited an H₂O₂ production rate of 1791 mmol g_cat⁻¹ h⁻¹. When employed as the cathode in ZABs, the system delivered a peak power density of 179 mW cm⁻² and maintained 93.5 % initial activity after 24 h of operation at 20 mA cm⁻². Furthermore, in a flow-state ZAB configuration, the catalyst delivered an integrated performance with a peak power density of 99.31 mW cm⁻² and an H₂O₂ yield of 33.55 mmol g_cat⁻¹ h⁻¹. This work highlights the potential of ZABs for in situ H₂O₂ production, thereby providing a technological foundation for developing multifunctional devices that integrate energy supply and chemical synthesis.