Co,Fe-ions intercalated Ni(OH)2 network-like nanosheet arrays as highly efficient non-noble catalyst for electro-oxidation of urea

Developing a highly active, low-cost, and durable nanostructured catalytic material is of significant interest in fuel cell applications owing to its efficient energy conversion, ease of preparation and operation, and reduced emission of pollutants. In this work, various ratio (0.01, 0.03, and 0.05 mmol) of cobalt (Co), and iron (Fe) doped nickel hydroxide (Ni(OH)₂) nanosheet arrays were grown on Ni foam surface (Co–Ni(OH)₂ and Fe–Ni(OH)₂) via a simple one-step process. The Co–Ni(OH)₂ and Fe–Ni(OH)₂ nanosheet array on Ni foam electrodes were explored as potential candidate towards electro-oxidation of urea. Notably, 0.03 mmol Co doped Ni(OH)₂/Ni foam electrode displayed lowest-onset oxidation potential (0.21 V) and enhanced electro-oxidation of urea (59.7 mA) owing to its large amount of electrocatalytic active sites, densely assembled nanosheet array structures with porous surfaces, and electronic diffusion channels, which might promote interface electrochemical reaction. In addition, synergistic effect between Co metal with Ni(OH)₂ has also promotes enhanced electro-oxidation of urea in contrast to Fe–Ni(OH)₂ nanosheet array, Ni(OH)₂, and Ni foam electrodes. Chronoamperometric i-t curve of Co–Ni(OH)₂/Ni foam electrode obviously exhibited higher catalytic current, highly stable and durable properties in contrast to Fe–Ni(OH)₂ nanosheet arrays. As-fabricated Co–Ni(OH)₂/Ni foam can be explored as a new type of potential low-cost catalyst for electro-oxidation of urea, which reveals promising use in future fuel cell energy applications.