Fabrication of MoS2 decorated reduced graphene oxide sheets from solid Mo-precursor for electrocatalytic hydrogen evolution reaction

Abstract

Contemporary research on electrochemistry revolves around fabricating cost effective catalysts using non-precious compounds for environmentally benign energy storage and production. Aiming at the engineering of such a proficient catalyst we report a novel synthesis of molybdenum disulfide (MoS2) particle decorated on reduced graphene oxide (rGO) sheets. We used low cost precursors like graphene oxide (GO), sodium dodecyl sulfate (SDS) thioacetamide (Tha) and an inexpensive Keggin compound, ammonium phosphomolybdate (APM) powder, in aqueous medium using simple hydrothermal procedures at the different stage of the synthesis. The as-prepared MoS2/rGO exhibits high catalytic ability for hydrogen evolution electrochemical reaction with ∼140 mV overpotential for a current density of 10 mA cm−2 for a catalyst loading of 0.1 mg cm−2 and a Tafel slope of 50 mV dec−1 measured in glassy carbon electrode. The low charge transfer resistance value Rct 26.56 Ω, is manifested in the enhanced HER performance due to faster electron transfer. In-house reduction of APM to MoS2 on in situ reduced rGO by Tha in aqueous medium, produced the effective 2D catalyst. This is the first report of one-pot synthesis of an in situ produced electrocatalyst i.e. MoS2 onto rGO from aqueous SDS solution using solid phase dispersion of the simplest Keggin compound.