Minireview of Coupled Electrochemical Hydrogen Production and Organic-Oxidation for Low Energy Consumption

Hydrogen production from electrochemical water splitting has attracted great attention due to its supply to green energy. However, commercial alkaline water electrolysis is energy intensive due to inert and large overpotentials of anodic oxygen evolution reaction (OER). Electro-oxidation of organics is an attractive alternative to the OER. With electro-oxidation of special organic substrates on an active anode, decreased cell voltage of H2 evolution can be achieved along with the production of value-added products. In this review, we summarize the latest progress on coupled H2 production with organic electro-oxidation systems. Different organic compounds containing oxygen (alcoholic hydroxyl, aldehydes, ketone), nitrogen, sulfides, and olefin/alkane groups have been selectively oxidized into high value-added products on the anodes, thereby promoting H2 evolution on the cathodes. Some complicated coupling reactions, such as the formation of C–C and C–N, are also introduced in the coupling systems. In addition, the challenges and prospects for the future development of this research field are highlighted.