One-step electrodeposition of Ni-Mo electrode with column-pyramid hierarchical structure for highly-efficient hydrogen evolution

Abstract

The construction of transition metal alloys with 3D structure facilitates their catalytic activity towards hydrogen evolution reaction. Although this can be achieved by the wet chemical and template strategies, the uncertainty of reaction process inevitably results in the difficulty of the repeatability of product synthesis. Herein, we present the rationally designed 3D Ni-Mo with a typical hierarchical structure on Ni foam by combing ‘hydrogen bubble template’ and ‘tip effect’ via one-step electrodeposition. This 3D Ni-Mo/NF has both regular columnar structures of micron level and widespread pyramidal-like nanoparticles, which only needs an overpotential of 53 mV and 161 mV to afford 10 mA cm−2 and 100 mA cm−2 for HER in 1 M KOH, respectively. In addition, a small Tafel slope (42.6 mV dec-1), and long-term operational stability are achieved on the catalyst. The excellent performance can be traced to the amorphous and hierarchical structure with favorable active sites. Furthermore, the network structure of the nickel foam substrate can promote the diffusion and infiltration of electrolyte. Impressively, this electrode exhibits super hydrophilic, which facilitates the detachment of bubbles. The free-standing 3D catalysts in this study can be synthesized in a facile and viable way, indicating their promising tactic for scaled-up water electrolysis.

Keywords

• 3D NiMo catalyst
• Hydrogen bubble template
• Hierarchical structure
• Bubble precipitation
• Hydrogen evolution