Ultra-high electrocatalytic activity of VS2 nanoflowers for efficient hydrogen evolution reaction

Abstract

It is a great challenge to explore cheap, abundant and eco-friendly electrocatalysts for hydrogen evolution reaction (HER). Here, we report the fabrication of VS₂ nanoflowers with 1T phase by a simple hydrothermal method and their electrocatalytic performance in the HER. We find that the VS₂ nanoflowers show comparable HER performance to Pt in acids, including an ultra-low onset potential of 32 mV, a Tafel slope of 34 mV dec⁻¹ which resembles that of Pt, and a small overpotential of 58 mV (54 mV for Pt) at a current density of 10 mA cm⁻². High stability and almost 100% faradaic efficiency indicate the practical application of VS₂ nanoflowers in the HER. Our first-principles calculations reveal that the thermoneutral Gibbs free energy of hydrogen adsorption on both the basal and edge sites of the 1T-VS₂ monolayer can be achieved under certain hydrogen coverage and the monolayer shows good conductivity, which contribute to the impressive catalytic performance of VS₂ nanoflowers. We expect that the VS₂ nanostructures may be applicable in electrocatalysis with high efficiency.