Accelerating Hydrogen Evolution by Anodic Electrosynthesis of Value-Added Chemicals in Water over Non-Precious Metal Electrocatalysts.

Integrating electrolytic hydrogen production from water with thermodynamically more favorable aqueous organic oxidation reactions is highly desired, because it can enhance the energy conversion efficiency in relation to traditional water electrolysis, and produce value-added chemicals instead of oxygen at the anode. In this Minireview, we introduce some key considerations for anodic auxiliary electrosynthesis and outline three types of electrocatalytic organic reactions including biomass derivative, alcohol and amine oxidation reactions, which can boost cathodic hydrogen generation. Furthermore, frequently used noble-metal-free electrocatalysts are classified into nickel-based, cobalt-based, other transition-metal-based and bimetallic electrocatalysts. The preparation methods of these catalysts and their performance towards electrochemical oxidation reactions are also discussed in detail. We specifically highlight the importance of redox active sites on the surface of the electrocatalysts, which act as electron mediators to promote oxidation reactions. Finally, the current challenges and future developments in this emerging field are also discussed.