Protonation-enhanced H2O2 electrosynthesis: high-selectivity and high-yield with a noble-metal-free CTF/BHN composite

The development of non-noble metal catalysts with high activity and selectivity is critical for the electrocatalytic production of hydrogen peroxide (H 2 O 2 ). Herein, we report a composite catalyst (CTF/BHN) fabricated by chelating a basic bismuth salt (BHN) with a bipyridine-containing covalent triazine framework (CTF), forming strong Bi-bipyridine bonds at the interface. This catalyst exhibits exceptional H 2 O 2 selectivity (92–98 %) over a wide potential range (0.3–0.62 V vs. RHE). In H-type cell tests, it achieves a Faraday efficiency of 88.9 % at 20 mA cm −2 , with a high H 2 O 2 production rate of 1.65 mol g −1 h −1 , and maintains stable performance for 42 h. In-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and X-ray photoelectron spectroscopy (XPS) reveal that the superior performance stems from synergistic interfacial effects: electron transfer from BHN to CTF enhances charge transport, while polarized interfaces promote water dissociation and protonation of pyridine groups in CTF to form Py*H intermediates. Py*H acts as a proton relay, facilitating the protonation of adsorbed *O 2 to *OOH at Bi active sites. Concurrently, the enhanced interaction between *OOH and the catalyst surface (evidenced by the blue-shifted *OOH peak) stabilizes *OOH and suppresses its dissociation, thereby driving the 2e − ORR pathway for efficient H 2 O 2 generation.