Abstract

Low Cell Voltage Electrosynthesis of Hydrogen Peroxide

Kai Wang, Associate Professor, Tsinghua University

Electrochemical oxygen reduction reaction (ORR) via a selective 2e- pathway offers a great opportunity for the synthesis of hydrogen peroxide as an alternative of traditional anthraquinone route. Unfortunately, the cell voltage of hydrogen peroxide electrosynthesis on neutral condition still requires improvement to meet the industrial demands, where high productivity and low input energy are desired. In this report, crucial impacts of reactor component on the relationship of cell voltage and current density and the over-potentials of each part of a flow cell reactor for hydrogen peroxide electrosynthesis are introduced, which indicate that the cathodic solution overpotential has a great contribution to the cell voltage. When applying thin cathodic solution channel, the hydrogen peroxide can be synthesized at 2.28 V cell voltage with 300 mA/cm² current density and 97.1% Faraday efficiency, corresponding to an energy consumption of 3.70 kWh/kg H₂O₂, which is much lower than the literature results. The produced hydrogen peroxide can be directly used for synthesizing high purity 2,2'-dibenzothiazole disulfide, showing the potential industrial value of hydrogen peroxide electrosynthesis technology. The authors acknowledge the support from National Natural Science Foundation of China (No. 22178194) and for this work.