McPhail, David S.

Permanent URI for this collectionhttps://hdl.handle.net/10735.1/5847

David S. McPhail is a Professor of Chemistry and holds the Edith O’Donnell Distinguished Chair of Conservation Science. His appointment allows him to work closely with the Edith O'Donnell Institute of Art History and the Dallas-Fort Worth area’s major art museums in collaborative research projects in conservation science.

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    Amorphous Molybdenum Sulfide on Graphene-Carbon Nanotube Hybrids as Supercapacitor Electrode Materials
    (Royal Society of Chemistry, 2017-01-20) Pham, K. -C; McPhail, David S.; Wee, A. T. S.; Chua, D. H. C.; McPhail, David S.
    Herein, we report the application of amorphous molybdenum sulfide (MoSx, x ≈ 3) as the main active material for supercapacitor electrodes. MoSx was deposited at room temperature onto a high specific surface area electrode made of graphene-carbon nanotube hybrids directly grown on carbon paper (GCNT/CP), using an electrochemical deposition method. The MoSₓ/GCNT/CP electrode showed high specific capacitance. A gravimetric specific capacitance of 414 F g⁻¹ was demonstrated at a constant discharge rate of 0.67 A g⁻¹. The deposition of MoSₓ onto a conductive, high surface area support played a crucial role for a high specific capacitance. An up to 4.5-fold enhancement in specific capacitance was demonstrated when MoSₓ was deposited on GCNT/CP as compared to MoSₓ deposited on a simple carbon paper support. The MoSₓ/GCNT/CP electrode is suggested to be a novel candidate for supercapacitor applications.
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    Analysis and Imaging of Biocidal Agrochemicals using ToF-SIMS
    (Springer Nature, 2017-09-06) Converso, Valerio; Fearn, Sarah; Ware, Ecaterina; McPhail, David S.; Flemming, Anthony J.; Bundy, Jacob G.; 0000 0001 2442 1174 (McPhail, DS); McPhail, David S.
    ToF-SIMS has been increasingly widely used in recent years to look at biological matrices, in particular for biomedical research, although there is still a lot of development needed to maximise the value of this technique in the life sciences. The main issue for biological matrices is the complexity of the mass spectra and therefore the difficulty to specifically and precisely detect analytes in the biological sample. Here we evaluated the use of ToF-SIMS in the agrochemical field, which remains a largely unexplored area for this technique. We profiled a large number of biocidal active ingredients (herbicides, fungicides, and insecticides); we then selected fludioxonil, a halogenated fungicide, as a model compound for more detailed study, including the effect of co-occurring biomolecules on detection limits. There was a wide range of sensitivity of the ToF-SIMS for the different active ingredient compounds, but fludioxonil was readily detected in real-world samples (wheat seeds coated with a commercial formulation). Fludioxonil did not penetrate the seed to any great depth, but was largely restricted to a layer coating the seed surface. ToF-SIMS has clear potential as a tool for not only detecting biocides in biological samples, but also mapping their distribution.

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