Three-Dimensional Hierarchical Nanostructured Cu/Ni–Co Coating Electrode for Hydrogen Evolution Reaction in Alkaline Media

In this work,three-dimensional hierarchical nickel–cobalt alloy coating for hydrogen evolution cathode was fabricated by electrodeposition processes.The coatings’morphology evolves from sea cucumber-like nanostructure to caterpillar-like one with the increase of cobalt content.A large amount of nanometric‘‘steps,’’served as the active sites for hydrogen evolution reaction,were observed.According to Tafel polarization measurements,the exchange current density of the as-synthesized coating with hierarchical nanostructure was 21.9 times compared with that of flat nickel coating.In addition,the hierarchical coating also displayed good electrochemical stability from the galvanostatic test.