Boosting electrochemical oxygen reduction to hydrogen peroxide coupled with organic oxidation

Abstract

Abstract The electrochemical oxygen reduction reaction (ORR) to produce hydrogen peroxide (H 2 O 2 ) is appealing due to its sustainability. However, its efficiency is compromised by the competing 4e − ORR pathway. In this work, we report a hierarchical carbon nanosheet array electrode with a single-atom Ni catalyst synthesized using organic molecule-intercalated layered double hydroxides as precursors. The electrode exhibits excellent 2e − ORR performance under alkaline conditions and achieves H 2 O 2 yield rates of 0.73 mol g cat −1 h −1 in the H-cell and 5.48 mol g cat −1 h −1 in the flow cell, outperforming most reported catalysts. The experimental results show that the Ni atoms selectively adsorb O 2 , while carbon nanosheets generate reactive hydrogen species, synergistically enhancing H 2 O 2 production. Furthermore, a coupling reaction system integrating the 2e − ORR with ethylene glycol oxidation significantly enhances H 2 O 2 yield rate to 7.30 mol g cat −1 h −1 while producing valuable glycolic acid. Moreover, we convert alkaline electrolyte containing H 2 O 2 directly into the downstream product sodium perborate to reduce the separation cost further. Techno-economic analysis validates the economic viability of this system.