Integrating H2O2 generation from electrochemical oxygen reduction with the selective oxidation of organics in a dual-membrane reactor

Abstract The electrochemical reduction of oxygen to H2O2 is a sustainable substitution for the current anthraquinone process. However, the concentration, transportation, and storage of H2O2 increases not only the cost but also the risks in safety. Herein, we report a method of coupling electrochemical production of H2O2 with its in situ application in the selective oxidation of organics in a dual-membrane microflow electrolyzer, where the OOH− generated from 2e− reduction of O2 at cathode subsequently oxidizes organic substrates into value-added products under the catalysis of TS-1. When applied to phenol oxidation, the selectivity to target catechol and hydroquinone is as high as 94.68% with an overall Faradic efficiency (FE) up to 30.25% at a conversion of 10.61% under the optimized condition. Further study revealed that this method is also feasible for the coupling of various other organic oxidation reactions such as alcohol oxidation, styrene epoxidation and ammoximation with high selectivity and FE. Additionally, an overall FE of 132.79% was achieved in the paired oxidation of furfural to furoic acid, where furfural was oxidized both indirectly via H2O2 generated on cathode and directly on the anode.