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.