Wafer scale and substrate-agnostic growth of MoS2 nanowalls for efficient electrocatalytic hydrogen generation in acidic and alkaline media

Abstract

Emerging as a promising alternative to expensive platinum-based catalysts for electrocatalytic hydrogen evolution reaction (HER), molybdenum disulfide (MoS2) stands out for its favourable thermodynamic properties. However, the catalytic activity of MoS2 is mostly confined to its edges while the basal plane remains inactive, limiting practical applicability. Fabrication of stable MoS2 structures with enhanced active sites on a given surface area still remains a complex task. Here we introduce a substrate-agnostic, metal-organic chemical vapour deposition (MOCVD) method for large-area 3D dendritic nanostructures of 2D MoS2, termed as “MoS2 nanowalls”. Using scanning and transmission electron microscopy (SEM/TEM), we elucidate the growth mechanism of the MoS2 nanowalls and their branched dendritic structure. Even subjected to extreme pH environments (0 and 14) during the HER, the grown MoS2 nanowalls show remarkable stability even after >170 hours of continuous operation and exhibit excellent catalytic activity with 10 mAcm−2 current density achievable by applying low overpotentials (309±2 mV at pH = 0 and 272±2 mV at pH = 14). The presented large-area growth method for inexpensive MoS2 nanowall based catalyst can pave the way for practical applications of water electrolysis cells operating at low voltages (≤1.5 V).

Keywords

• Hydrogen evolution reaction
• 2D materials
• Metal-organic chemical vapour deposition
• Transition metal dichalcogenides
• MoS2