Highly efficient electroreduction of oxygen to hydrogen peroxide on carbon catalyst via electrode-electrolyte interface engineering

Abstract

Electrosynthesis of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (ORR) represents a green alternative route to the conventional energy-intensive anthraquinone process. Nevertheless, the catalytic efficiency of the state-of-the-art electrocatalysts still has large space to improve. Herein, we demonstrate that the electrocatalytic performance of acetylene black can be tailored by regulating the electrode–electrolyte interfacial structure using ionic liquid (IL) and surfactant. The present research disclosed that the catalytic activity is closely related to alkyl chain length of the IL cation. The presence of the IL can increase the electrocatalytic selectivity of H2O2 from 48 % to 90 %. Moreover, the selectivity of H2O2 can even be further improved up to 99 % by adding cationic surfactant in the electrolyte due to the facilitated desorption of HO2– at the electrode interface, and this high selectivity can be well maintained for 100 h. This work emphasizes the importance of rational design and regulation of the cathode-electrolyte interface for improving the ORR activity, shedding light on the potential practical application of electrosynthesis of hydrogen peroxide.