Electrochemical production of H2O2 with 100% current efficiency and strong stability by adjusting the interfacial side reactions of air-breathing cathodes

Abstract

The catalyst selectivity, oxygen mass transfer, and electron transfer at the cathode interface are three important factors for efficient H2O2 production in electrocatalytic oxygen reduction reaction (ORR). In this work, we optimize the superhydrophobic carbon black-graphite dual-layer air-breathing cathode and improve its long-term operational stability by simplifying the electrode structure, adjusting the catalytic interface, and optimizing the matrix current collector material. The results showed calcination method can significantly increase the hydrophobicity of the catalytic layer (CL) and form a long-term stable solid–liquid-gas three-phase interface, thereby improving the H2O2 production and long-term operation stability of the cathode. The H2O2 yield of the calcined stainless steel mesh matrix cathode was 571 ± 7 mg L-1h−1 under single-chamber condition at 20 mA cm -2, which was 40% higher than that of the uncalcined cathode. In addition, using titanium mesh as the matrix, the H2O2 yields reached 320 ± 2, 630 ± 1 mg L-1h−1 at 10 and 20 mA cm -2, respectively, and the current efficiencies reached 100% and 99%, respectively. Our optimization of the hydrophobic air-breathing cathode provides new insights into the efficient production of H2O2 and new insights into the practical application and scale-up of future cathodes.