Recent Progress on Strategies for Electrochemical Hydrogen Production Coupling with Oxidation of Inorganic Chemicals

Electrochemical water splitting to produce H-2 has drawn much attention for inherent advantages. However,the sluggish reaction kinetics of anodic oxygen evolution reaction (OER) and high energy consumption greatly limited its application. In contrast to OER, the electrooxidation of some inorganic chemicals is more thermodynamically and kinetically favorable. Therefore,coupling hydrogen evolution reaction (HER)with inorganic alterna. tives oxidization shows great potential to enhance the efficiency of H-2 production. It can obviously lower the anodic overpotential compared with OER. Simultaneously,some pollutants can be removed or some valuable chemicals can be produced on the anode. In this review,we will summarize the recent progress on the strategy of H-2 production coupling with the electrooxidation of inorganic chemicals. Firstly,some representative inorganic alternatives are introduced and discussed,including nitrogenous N2H4 and NO and sulfureted H2S and SO2, which can assist to produce H-2 at very low cell voltage and radically avoid the generation of O-2. And then introducing electrochemical neutralization energy to further decrease the cell voltage of electrochemical H-2 production or even achieve H-2 production together with electricity output are further discussed. Finally,the remaining challenges and perspectives are also provided for future development.