Engineering Localized Alkalinity and Oxygen Enrichment for Efficient Acidic O2‐to‐H2O2 Electroreduction via Carbon‐Based Triphase Interfaces

Abstract The sustainable production of hydrogen peroxide (H 2 O 2 ) via the two‐electron oxygen reduction reaction (2e⁻ ORR) on carbon‐based catalysts offers a compelling alternative to the energy‐intensive anthraquinone process. However, the slow kinetics of the 2e⁻ ORR in acidic media limits its efficiency. Herein, a novel strategy is introduced to overcome this limitation by engineering a needle‐shaped hydrophobic carbon felt embedded with hard carbon as a natural air diffusion electrode (ADE). In situ and ex situ characterization show this design creates an oxygen‐enriched, locally alkaline microenvironment at the triphase interface, which accelerates 2e⁻ ORR kinetics by confining oxygen enrichment within the hard carbon layer. Quantitatively, this oxygen‐enriched hydrothermal carbon electrocatalyst achieves a remarkable H 2 O 2 selectivity of 95.47% at near‐zero overpotential and a high production rate of 487.82 mg L −1 h −1 at 200 mA cm −2 . Furthermore, density functional theory calculations reveal that the carboxyl and ether functional groups in hydrothermal hard carbon optimize O 2 * and OOH * adsorption, promoting the desired 2e⁻ pathway. Importantly, this ADE design not only exhibits exceptional performance and long‐term stability but also demonstrates a significantly reduced global warming potential compared to conventional methods, highlighting its potential to revolutionize industrial‐scale H 2 O 2 electrosynthesis by replacing commercial carbon black‐based cathodes.