Nickel Vacancies Boost Reconstruction in Nickel Hydroxide Electrocatalyst

Because the reconstruction of catalysts is generally observed during oxidation reactions, understanding the intrinsic structure-related reconstruction ability of electrocatalysts is highly desirable but challenging. Herein, a controllable hydrolysis strategy is developed to obtain nickel hydroxide electrocatalysts with controllable nickel vacancy (VNi) concentrations, as confirmed by advanced spectroscopic characterization. Electrochemical measurements show that the reconstruction can be promoted with the increase of VNi concentration to generate true active components, thereby boosting activities for both oxygen evolution reaction (OER) and urea oxidation reaction (UOR). Density functional theory calculations confirm that the increased VNi concentration yields decreased formation energies of the true active components during reactions. This work provides fundamental understanding of the reconstruction ability of electrocatalysts in anodic oxidation reactions from the view of intrinsic defects.