Tuning Local Proton Concentration and *OOH Intermediate Generation for Efficient Acidic H₂O₂ Electrosynthesis at...

Electrocatalytic oxygen reduction is a sustainable method for on-site H₂O₂ synthesis. The H₂O₂ in acidic media has wide downstream applications, but acidic H₂O₂ electrosynthesis suffers from poor efficiency due to high proton concentration and unfavourable *OOH (key intermediate) generation. Herein, acidic H₂O₂ electrosynthesis was enhanced by regulating local proton availability and *OOH generation via fluorine-doped on inner and outer walls of carbon nanotubes (F-CNTs). It was efficient and stable for H₂O₂ electrosynthesis with Faradaic efficiency of 95.6% and H₂O₂ yield of 606.6 mg cm^-2 h^-1 at 1.0 A cm^-2 and 0.05 M H₂SO₄, outperforming the state-of-the-art electrocatalysts. The F-doping regulated the electronic structure of CNTs with elevated p-band center, and F-doping on its inner and outer walls also enhanced nanoconfinement effect and superhydrophobicity, respectively. As a result, a local alkaline microenvironment was created on F-CNTs surface during acidic H₂O₂ electrosynthesis. The energy barrier for *OOH generation was significantly reduced and oxygen mass transfer was boosted. Their synergistic effects promoted acidic H₂O₂ electrosynthesis. This work provides new insights into the mechanism for regulating H₂O₂ electrosynthesis.