Ultra-small ReS2 nanoparticles hybridized with rGO as cathode and anode catalysts towards hydrogen evolution reaction and methanol electro-oxidation for DMFC in acidic and alkaline media

Abstract

Cost-effective non-noble metal electrocatalysts are of crucial significance to the successful use of direct methanol fuel cells (DMFCs) and hydrogen generation. Rhenium sulfide (ReS2) is a semiconducting transition metal dichalcogenide with very week interconnect between its layers. Herein, we report ReS2/reduced graphene oxide nanocomposite (ReS2/rGO) for advanced dual-applications towards methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER) in acidic and alkaline medium. For MOR, ReS2/rGO catalyst displays 198 μA cm–2 in alkaline and 38 μA cm–2 in acidic media. Also, the ReS2/rGO reveals a maximum power density of 38.6 mW cm−2 and 14.5 mW cm−2 at 60 °C in alkaline and acidic media, respectively. For HER, the Tafel slope of 67 mV dec–1 and 92 mV dec–1 and overpotential of 148 mV and 296 mV at the current density of 100 mA cm−2 obtain in acidic and alkaline media, respectively. Also, ReS2/rGO shows the double-layer capacitance of 1200 μF cm-2 and charge transfer resistance of 99 Ω. These excellent performances are assigned to the separated thin layers of ReS2 that increase specific surface area and edge sites of the catalyst and the presence of rGO, which increases the conductivity of catalyst.