Vertically Grown MoS₂ Nanoplates on VN with an Enlarged Surface Area as an Efficient and Stable Electrocatalyst for HER

Abstract

Layered MoS2 has attracted increasing interests as a promising low-cost alternative to Pt-based electrocatalysts for the hydrogen evolution reaction (HER). As is known to all, insufficient active sites and poor conductivity of MoS2 impede the improvement of its catalytic efficiency. In this work, the vanadium nitride (VN) with an enlarged specific surface area (VN(CTAB), CTAB refers to hexadecyltrimethylammonium bromide) was prepared as a substrate, and MoS2 nanoplates were vertically grown on the obtained VN(CTAB) for the first time. The synthesized MoS2–VN(CTAB) as an electrocatalyst for HER performs a low onset overpotential (85 mV) and small Tafel slope (53.31 mV dec–1) as well as superior stability. Besides the benefits from higher conductivity (106 S m–1) and greater stability of VN(CTAB) beyond the traditional carbon-based substrates, the expanded interlayer spacing (1.00 nm) and extra defects along with the lower valence states of Mo and S due to the stronger electron interaction between VN(CTAB) and MoS2 also effectively contribute to the excellent catalytic performance of MoS2–VN(CTAB). This study shows a new method to design efficient and stable HER electrocatalysts by means of non-carbon substrates.