Engineering composition and structure of binder-free MoS 2 anchored to carbon cloth for enhanced hydrogen evolution performance

Molybdenum disulphide (MoS 2 ) has received enormous attention as an alternative to noble metal based electrocatalysts for efficient H 2 production through water splitting. However, the limited number of active sites and low inherent electrical conductivity hinder the performance of bulk MoS 2 for electrocatalytic applications. Using hydrothermal synthesis, binder-free electrodes consisting of nano-crystalline MoS 2 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 MoS 2 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 MoS 2 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 MoS 2 based catalysts for optimised HER performance. • HER performance of supported MoS 2 electrocatalysts strongly depends on growth conditions. • Optimal electrocatalytic performance is found at an intermediate growth temperature. • Lowest overpotential (98 ± 3 mV) corresponds to the lowest CTR (7.9 Ω ). • η 10 , CTR and Tafel slope depend on the interplay of composition, phase morphology and crystallinity.