Synthesis of Stable and Efficient Electrocatalysts for Hydrogen Evolution: Hierarchical NiMo-Based Hollow Nanotubes

Abstract

Large-scale development of low-cost, efficient, and stable powder electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solutions is a key step toward commercial hydrogen production. Herein, a hierarchical NiMo-MoO3-x hollow nanotube (NiMo-MoO3-x-HNT) with bifunctional groups as an efficient HER electrocatalyst was strategically invented using an MoO3 nanorod (MoO3-NR) as the precursor. The synthesis mechanism of the NiMo-MoO3-x-HNT is established based on in-depth investigations using diffraction, spectral, and microscopy results. Experimental results suggest that the NiMo-MoO3-x-HNT exhibits excellent electrocatalytic HER performance in 1 M KOH, with a low overpotential of 26.5 mV@10.0 mA cm-2 and a small Tafel slope of 32.6 mV dec-1. These values are comparable to those of cutting-edge electrocatalysts based on platinum-group metals. Moreover, it exhibits an almost unaffected cyclic stability over 50,000 cycles and robust durability over 98 h. This remarkable performance is attributed to its bifunctional groups and the porous hierarchical hollow nanotubular morphology. In summary, this study proposes a novel, efficient, and cost-effective strategy for the development of noble metal-free, high-performance HER electrocatalysts.