Molecular Precursor Approaches to Scalable Molybdenum Disulfide Production for Water Electrolysis

UoM administered thesis: Phd

  • Authors:
  • Eliott Higgins

Abstract

The scalable synthesis of two-dimensional (2D) materials is a prerequisite for their commercial exploitation. Herein, this thesis reports two scalable methodologies for producing nanoscale molybdenum disulfide (MoS2) from the decomposition of a molecular precursor (tetrakis(N,N-diethyldithiocarbamato) molybdenum(IV)). The first method utilises a liquid-liquid interface to form a nanocrystalline thin film of MoS2 and is believed to be the first reported room temperature synthesis of transition metal dichalcogenides. The second method uses the precursor as an aerosol within a chemical vapour deposition process to generate a large area, homogeneous, edge-aligned film of MoS2. This methodology provides a one-step synthetic route to preparing prospective electrocatalysts and the film morphology was optimised to maximise the hydrogen evolution electrocatalytic performance. These same films were spontaneously decorated with nanoparticle gold (2.9 nm) in nanoscale loading amounts (0.044 μg cm-2) to further enhance the overall and intrinsic activity of these materials for hydrogen evolution catalysis. Both MoS2 and gold decorated MoS2 (AuNP@MoS2) electrodes were evaluated for their overall and intrinsic catalytic activity by DC and AC electrochemical techniques. Finally the sustainability and scalability of these electrodes was evaluated and it is shown that although the AuNP@MoS2 electrode is more sustainable than Pt based electrodes, to be considered as a future replacement material in an electrolyser the overpotential for hydrogen evolution for earth abundant catalysts needs to be within 70 mV of Pt.

Details

Original languageEnglish
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Award date31 Dec 2021