Electrocatalytic Hydrogenation and Oxidation in Aqueous Conditions†

Water molecule contains one oxygen and two hydrogen atoms, making it a potential oxygen and hydrogen source. Electrocatalytic organic reduction and oxidation using water as oxygen and/or hydrogen donors provide an environmentally friendly and sustainable strategy to replace traditional chemical‐driven stoichiometric reactions that use sacrificial reagents. Furthermore, the development of electrochemical synthesis provides a potential application for low tension photoelectricity, which is not cost‐effective during boosted voltage and application. In the last decade, electrocatalytic redox reactions of organic molecules in aqueous media had shown progress owing to the development of electrode materials and water‐splitting technology. This paper highlights several electrocatalytic systems and corresponding mechanisms for both hydrogenation and oxidative transformation of representative compounds. The activation process of protons and water on the working electrode surface has received special focus. Furthermore, paired electrolysis using water as the oxygen and hydrogen source has been demonstrated. This paired system combines hydrogenation and oxidation half‐reactions in one cell using water as the hydrogen and oxygen source, resulting in high atomic and electron utilization rates.