Electronic Tuning of Co, Ni‐Based Nanostructured (Hydr)oxides for Aqueous Electrocatalysis

Co, Ni‐based (hydr)oxides with stoichiometric or nonstoichiometric composites are playing significant roles in renewable energy technologies, such as electrocatalytic reactions for transforming earth abundant resources into value‐added chemicals. In the past several years, attributed to the development of novel synthesis strategies, characterization techniques, and theoretical calculations, the rational design and realization of a variety of Co, Ni‐based (hydr)oxides with exciting performances have been demonstrated. Particularly, the electrocatalytic reactivities of these Co, Ni‐based (hydr)oxides are highly dependent on their surface electronic structures, which can be well tuned by their nanostructures and compositions. This Review summarizes recent research advances in regulating electronic structures toward the optimization of electrochemical reactivity in aqueous solutions. These research works mainly focus on three important clean energy reactions: i) water oxidation, ii) oxygen reduction, and iii) carbon dioxide reduction, where the developments of advanced electrocatalysts can enable the production of value‐added chemicals or fuels. Furthermore, the electronic structure–property relationships behind the enhanced electrocatalytic properties of these Co, Ni‐based (hydr)oxides are also discussed. This Review covers recent research advances in regulating electronic structures toward the optimization of electrochemical reactivity in aqueous solutions, mainly focusing on three important clean energy reactions: i) water oxidation, ii) oxygen reduction, and iii) carbon dioxide reduction.