Facile fabrication of nickel nanostructures on a copper-based template via a galvanic replacement reaction in a deep eutectic solvent

•Ni nanostructures are synthesized via a galvanic replacement reaction in ethaline without chemical reducing agents.•The evolution of the morphology and topography of the nickel nanostructures is investigated.•Well-defined nanoporous Ni films with high HER electrocatalytic activity are fabricated in ethaline using an NPC template.

We describe an unusual galvanic replacement process for facile synthesis of nickel nanostructures by using Cu as a sacrificial template in a deep eutectic solvent (DES), ethaline. This replacement process occurred through a galvanic exchange of [NiCl4]2 − ions in ethaline at 353 K with an immersed Cu substrate, which acted as both reactive template and reductant. The mechanism for this replacement reaction and the morphology and topography evolution process of the nickel nanostructures were investigated. This facile preparation method performed in ethaline provides a novel way to fabricate nickel nanostructures with particulate or porous architecture on a copper-based template.

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