2D nanosheet molybdenum disulphide (MoS₂) modified electrodes explored towards the hydrogen evolution reaction

Abstract

We explore the use of two-dimensional (2D) MoS2 nanosheets as an electrocatalyst for the Hydrogen Evolution Reaction (HER). Using four commonly employed commercially available carbon based electrode support materials, namely edge plane pyrolytic graphite (EPPG), glassy carbon (GC), boron-doped diamond (BDD) and screen-printed graphite electrodes (SPE), we critically evaluate the reported electrocatalytic performance of unmodified and MoS2 modified electrodes towards the HER. Surprisingly, current literature focuses almost exclusively on the use of GC as an underlying support electrode upon which HER materials are immobilised. 2D MoS2 nanosheet modified electrodes are found to exhibit a coverage dependant electrocatalytic effect towards the HER. Modification of the supporting electrode surface with an optimal mass of 2D MoS2 nanosheets results in a lowering of the HER onset potential by ca. 0.33, 0.57, 0.29 and 0.31 V at EPPG, GC, SPE and BDD electrodes compared to their unmodified counterparts respectively. The lowering of the HER onset potential is associated with each supporting electrode's individual electron transfer kinetics/properties and is thus distinct. The effect of MoS2 coverage is also explored. We reveal that its ability to catalyse the HER is dependent on the mass deposited until a critical mass of 2D MoS2 nanosheets is achieved, after which its electrocatalytic benefits and/or surface stability curtail. The active surface site density and turn over frequency for the 2D MoS2 nanosheets is determined, characterised and found to be dependent on both the coverage of 2D MoS2 nanosheets and the underlying/supporting substrate. This work is essential for those designing, fabricating and consequently electrochemically testing 2D nanosheet materials for the HER.

The Mediatorless Electroanalytical Sensing of Sulfide Utilizing Unmodified Graphitic Electrode Materials

“…This places the electrodes in the following order of reactivity: SPE > EPPGE > GCE > BDDE > BPPGE. It is noted that the value for the SPEs are consistent with those in previous literature [44][45][46]. As the peak-to-peak separations for these carbon based electrodes are similar when utilizing hexammineruthenium(III) chloride, ( Table 2) further benchmarking was undertaken using the Fe 2+ /Fe 3+ redox couple, since this is an inner-sphere probe that is known to be extremely sensitive to surface orientated functional groups, especially carbonyl groups.…”

Graphene Encapsulated Silicon Carbide Nanocomposites for High and Low Power Energy Storage Applications

“…With the ever-increasing ecological demand for the utilisation of renewable energy sources, such as solar and wind, the development of sustainable energy conversion and storage technologies are paramount [1][2][3]. One of the most successful (in terms of commercialisation) effective energy storage devices has been the lithium-ion battery (LIB).…”

Surfactant-exfoliated 2D molybdenum disulphide (2D-MoS2): the role of surfactant upon the hydrogen evolution reaction

“…However, the requirement of expensive platinum (Pt) as an catalytic electrode material in both electrolysers and fuel cells has severely limited the cost competitiveness of a hydrogen based energy economy. 3 In order to lower the production costs associated with H 2 (gas), research has recently focused on nding a cheaper more earth abundant electrode material to catalyse the Hydrogen Evolution Reaction (HER) (2H + + 2e À / H 2 ), 4 which is the focus of commercially available electrolysers. Studies such as Ji et al 5 have shown that 2D-MoS 2 can be used as an effective electrocatalyst towards the HER.…”

“…2(A). 3 For details on how the Tafel slopes displayed in Fig. 2(B) )) is subsequently followed by a decrease in current density and/or plateauing effect.…”