Enhanced hydrogen evolution and symmetric supercapacitor performance of a Ru-doped multiphase WS₂ electrode

It is well known that the electrochemical energy generation and storage performance of two-dimensional layered transition metal dichalcogenides (for example, MoS₂ and WS₂) strongly depend on the phase and properties of the electrode material. In this work, we report that 2H/1T phase coupling induced by Ru doping leads to improved electrochemical symmetric supercapacitor and hydrogen evolution reaction (HER) performance of a WS₂ nanosheet electrode. XRD and Raman studies indicate that a 2H/1T multiphase emerges in WS₂ nanosheets for the sample with 10 at% Ru (2H/1T-WS₂-10) and other samples retain the parent 2H phase at a low Ru doping level. The 2H/1T-WS₂-10 electrode with excellent catalytic activity delivers a 113 mV overpotential at a 10 mA cm⁻² current density in 0.5 M H₂SO₄ electrolyte. Furthermore, the same electrode exhibits superior symmetric supercapacitor performance with high specific capacitance (664 F g⁻¹@1 A g⁻¹) and energy density (92 W h kg⁻¹@1 A g⁻¹) in 1 M Na₂SO₄ electrolyte. This work opens the way for the multifunctional use of doped WS₂ for electrochemical energy conversion and storage applications.