Multi-level high hydrophilicity nanostructure electrocatalyst to promote H2 removal for efficient hydrogen evolution reaction

Abstract

For large-scale utilization of renewable energy, the production of green hydrogen as energy carrier is efficacious through water electrolysis. The development of low-cost electrocatalysts for the hydrogen evolution reaction (HER) is critical. Herein, the control synthesis of NF-Co₃O₄-Ni(OH)₂-Co(OH)₂ with multi-level nanostructure was proposed by the multi-step hydrothermal-electrodeposition strategy. With rational multi-layer structure design, the catalyst based on non-precious metals had larger specific surface area and exposure of more active sites, giving efficient HER catalytic activity. Upon optimization of synthesis process, the electrocatalyst displayed a Tafel slope of 84 mV·dec⁻¹ and overpotential of 42 mV at a current density of 10 mA·cm⁻² in 1.0 mol·L⁻¹ KOH solution, which was only slightly lower than that of commercial Pt/C@NF catalyst (corresponding value of 30 mV and 54 mV·dec⁻¹). In a 40-hour stability test, the fabricated catalyst was electrochemically stable, showing negligible performance degradation. Moreover, with the multi-level nanostructure, the electrode exhibited high hydrophilicity and aerophobia properties. This work has demonstrated that the rational design of multi-level nanostructures is an effective strategy to synthesize high-performance HER electrocatalyst with non-precious materials.