Mass-producible 2D-WS2 bulk modified screen printed electrodes towards the hydrogen evolution reaction

Abstract

A screen-printable ink that contained varying percentage mass incorporations of two dimensional tungsten disulphide (2D-WS₂) was produced and utilized to fabricate bespoke printed electrodes (2D-WS₂-SPEs). These WS₂-SPEs were then rigorously tested towards the Hydrogen Evolution Reaction (HER) within an acidic media. The mass incorporation of 2D-WS₂ into the 2D-WS₂-SPEs was found to critically affect the observed HER catalysis with the larger mass incorporations resulting in more beneficial catalysis. The optimal (largest possible mass of 2D-WS₂ incorporation) was the 2D-WS₂-SPE_40%, which displayed a HER onset potential, Tafel slope value and Turn over Frequency (ToF) of −214 mV (vs. RHE), 51.1 mV dec⁻¹ and 2.20 , respectively. These values significantly exceeded the HER catalysis of a bare/unmodified SPE, which had a HER onset and Tafel slope value of −459 mV (vs. RHE) and 118 mV dec⁻¹, respectively. Clearly, indicating a strong electrocatalytic response from the 2D-WS₂-SPEs. An investigation of the signal stability of the 2D-WS₂-SPEs was conducted by performing 1000 repeat cyclic voltammograms (CVs) using a 2D-WS₂-SPE_10% as a representative example. The 2D-WS₂-SPE_10% displayed remarkable stability with no variance in the HER onset potential of ca. −268 mV (vs. RHE) and a 44.4% increase in the achievable current over the duration of the 1000 CVs. The technique utilized to fabricate these 2D-WS₂-SPEs can be implemented for a plethora of different materials in order to produce large numbers of uniform and highly reproducible electrodes with bespoke electrochemical signal outputs.