Tuning Local Proton Concentration and *OOH Intermediate Generation for Efficient Acidic H ₂ O ₂ Electrosynthesis at Ampere‐Level Current Density

Abstract Electrocatalytic oxygen reduction is a sustainable method for on‐site H 2 O 2 synthesis. The H 2 O 2 in acidic media has wide downstream applications, but acidic H 2 O 2 electrosynthesis suffers from poor efficiency due to high proton concentration and unfavourable *OOH (key intermediate) generation. Herein, acidic H 2 O 2 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 H 2 O 2 electrosynthesis with Faradaic efficiency of 95.6% and H 2 O 2 yield of 606.6 mg cm −2 h −1 at 1.0 A cm −2 and 0.05 M H 2 SO 4 , 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 H 2 O 2 electrosynthesis. The energy barrier for *OOH generation was significantly reduced and oxygen mass transfer was boosted. Their synergistic effects promoted acidic H 2 O 2 electrosynthesis. This work provides new insights into the mechanism for regulating H 2 O 2 electrosynthesis.