Engineering composition and structure of binder-free MoS2 anchored to carbon cloth for enhanced hydrogen evolution performance

Molybdenum disulphide (MoS2) has received enormous attention as an alternative to noble metal based electrocatalysts for efficient H production through water splitting. However, the limited number of active sites and low inherent electrical conductivity hinder the performance of bulk MoS2 for electrocatalytic applications. Using hydrothermal synthesis, binder-free electrodes consisting of nano-crystalline MoS2 anchored to carbon cloth (CC) have been produced, for which synthesis temperature has been shown to have a significant impact on electrocatalytic behaviour. Increasing synthesis temperature is found to reduce MoS2 sub-stoichiometry, reduce oxide content and increase crystallinity. Optimal performance is achieved for electrodes produced at intermediate synthesis temperatures (230 °C) which show an overpotential of 98 ± 3 mV to reach a current density of 10 mA cm−2 and a Tafel slope of 108 ± 5 mV dec−1. Samples grown under these conditions possess the best combination of active site concentration, morphology and proportion of metallic 1T MoS2 for an enhanced Hydrogen Evolution Reaction (HER) activity. These results reflect the need to consider the interplay of elemental composition, phase composition and structure in engineering HER catalysts and provides an effective route to tune the electrocatalytic activity of layered MoS2 based catalysts for optimised HER performance.