Optimization of H2O2 production in a small-scale off-grid buffer layer flow cell equipped with Cobalt@N-doped graphitic carbon core-shell nanohybrid electrocatalyst

Electrochemical oxygen reduction (ORR) to hydrogen peroxide (H2O2) is emerging as a sustainable approach for the production of 'green' H2O2 requiring only oxygen and electricity compared to the energy intensive anthraquinone process. High 2e selectivity is required in order to boost faradaic and energy efficiency (FE) of the process. Upon correct tuning of their properties, nitrogen-doped carbon materials are excellent candidates as electrocatalyst for H2O2 electrosynthesis due to their chemical and electrochemical resistance and 2e selectivity. Furthermore, careful cell design and parameter optimization are mandatory for an industrial scale up of the process. In this study, a Cobalt@N-doped graphitic carbon core-shell nanohybrid (CS(Co)-N-GC) electrocatalyst was studied in a buffer layer complete cell equipped with a proton exchange membrane in order to determine the effect of flow rate and potential on process selectivity and energy efficiency. After optimization, the cell was able to produce 0.5 wt% H2O2 with an average FE higher than 40%, an energy consumption lower than 8 kWh/kgH2O2 and a production rate of 1.2 g/h gcat @ 0.3 V vs RHE with the possibility to produce up to 1 wt% H2O2. (c) 2022 Elsevier Ltd. All rights reserved.