MoS2-based materials as alternative cathode catalyst for PEM electrolysis

Abstract

<p> Pt and Ir are the popular catalysts for electrochemical water splitting, but their low abundance on Earth&rsquo;s crust and high price render them unsustainable for future use. In the quest for alternative catalyst materials, a popular hydro-treating catalyst, molybdenum disulphide (MoS₂), has been found to be promising for hydrogen evolution reaction (HER). Two types of MoS₂-carbon composites, (i) physical mixture of MoS₂ and carbon black (Vulcan^&reg;) and (ii) MoS₂ supported on reduced graphene oxide (RGO), were examined. Among the MoS₂-based materials tested, 47 wt% MoS₂/Vulcan^&reg; gave the best performance in terms of current density at an encouraging level for practical application. The poor performance of bare MoS₂ was attributed to its poor electrical conductivity. No indication of performance deterioration was observed for 18 h of continuous operation at 2.0 V cell voltage with 47 wt% MoS₂/Vulcan^&reg;. MoS₂/RGO hybrids showed HER activity, which was considerably higher than that of bare MoS₂.</p>