Preparation of fluorine-doped α-Ni hydroxides as alkaline water electrolysis catalysts via the liquid phase deposition method†

A room-temperature liquid phase process was utilized to prepare α-Ni(OH)₂ thin films with high crystallinity for use as oxygen evolution reaction catalysts under strongly alkaline conditions. It was discovered that the catalytic activity of the prepared catalyst is sensitive to pH during the liquid phase process. Specifically, under optimized reaction conditions, we found that the synthesized α-Ni(OH)₂ thin film showed relatively high catalytic activity and high stability across potential scans. Our structural analyses revealed that the fluorine incorporation within the framework of α-Ni(OH)₂ was the origin of the high catalytic activity. And also, the catalytic activity depending on the sample preparation conditions was discussed through the ex situ and in situ measurements of the electrode surface. This work provides insights into the potential of the solution process for preparing high crystal materials with high reproducibility as an electrode preparation procedure.