Cathodic Hydrogen Peroxide Electrosynthesis Using Anthraquinone Modified Carbon Nitride on Gas Diffusion Electrode

Electrochemical synthesis of hydrogen peroxide from oxygen and water can be a cost-effective and energy-efficient alternative to the traditional approach which requires high energy input and expensive noble metal catalysts and has a large CO2 footprint. The availability of selective electrocatalysts and performance validation of a device represent current research needs toward this goal. Herein, we report an efficient electrocatalytic system for hydrogen peroxide production based on anthraquinone molecular catalysts which are tethered onto carbon nitride (C3N4) conductive supports. Anthraquinone enables highly selective synthesis of hydrogen peroxide via two-electron oxygen reduction. The optimal electrolyte pH was identified to both facilitate H2O2 electrochemical synthesis and minimize H2O2 decomposition. The anthraquinone-functionalized C3N4 supports were then adapted into a gas diffusion cathode configuration to greatly enhance the mass transport of oxygen reactants. The device fabricated in this study achieved an optimal H2O2 production rate of 60.1 mmol gcatalyst–1 h–1 at a maximum Faradaic efficiency of 42.2%.