Advances in Nickel-Based Catalysts for Alkaline Water Electrolysis: Comprehensive Review of Current Research Direction for HER and OER Applications.

Nickel-based catalysts are among the most promising materials for electrocatalytic water splitting, particularly for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. Their abundance, cost-effectiveness, and tunable electrochemical properties make them attractive alternatives to precious metal catalysts. This review provides a comprehensive analysis of the advancements in nickel-based catalysts, including pure nickel, alloys, oxides, hydroxides, and spinels, emphasizing their synthesis methods, structural properties, and electrocatalytic performance.