Nanostructured Cobalt-Based Electrocatalysts for Urea Oxidation: Mechanistic Insights, Nanoengineering Strategies, and Application Perspectives.

Electrochemical urea oxidation (UOR) enables energy-efficient hydrogen production coupled with wastewater remediation, representing a promising sustainable technology. Nanostructured cobalt-based catalysts have emerged as leading UOR candidates due to their tunable electronic structures, high intrinsic activity, and excellent stability. This review critically analyzes cobalt's mechanistic role in nickel oxyhydroxides, focusing on how Co doping modulates electronic structures, optimizes reaction pathways, and breaks the scaling relations limiting pure Ni catalysts. We summarize diverse nanoengineering strategies that synergistically enhance active site exposure, charge transfer kinetics and anti-deactivation performance. Key challenges (catalyst poisoning, sluggish multielectron kinetics, byproduct formation) and emerging solutions are discussed. Finally, we outline prospects for integrating advanced Co-based UOR catalysts into large-scale electrolysis systems to accelerate commercialization.