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Greg M. Swain

Professor

 
Professor (b. 1962). B.A., 1985, University of Texas at Dallas; Ph.D., 1991, University of Kansas; Postdoctoral Research Fellow, 1991-92, Space Power Institute and the Department of Chemical Engineering, Auburn University; JSPS Postdoctoral Research Fellow, 1992-93, Tohoku University, Japan; Assistant Professor of Chemistry, 1994-98, Utah State University; Associate Professor of Chemistry and Associate Department Head, 1998-2000, Utah State University. Analytical Chemistry and Materials Science; electroanalytical chemistry; electrochemical reaction mechanisms; new electrode materials; spectroscopic and microscopic probes of solid-liquid interfaces; flow injection analysis and separation science coupled with electrochemical detection; spectroelectrochemistry.

Our research is focused on understanding how the physicochemical properties of advanced carbon electrodes influence the heterogeneous electron transfer kinetics and reaction mechanisms of various aqueous and non-aqueous redox analytes. Currently, much of our effort is with electrically conducting microcrys­tal­line and nano­crystalline diamond thin films, and applying these materials in various electro­chemical technologies. The diamond films are deposited in our laboratory using microwave-assisted chemical vapor deposition. In addition to a variety of electrochemical methods of analysis, some of the tools routinely used for character­ization include Raman, FT-IR and UV-Vis spectro­scopies, scanning electron ­microscopy, in situ scanning probe microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy.

Structure-Reactivity. Research is being conducted to understand how the electrochemical properties of diamond (both microcrystalline and nanocrys­tal­line films) are influenced by the doping type and level, the surface termination (H,O, and F), the non-diamond carbon impurity content, the morphological defects and grain boundaries, and the primary crystallographic orientation. A variety of aqueous and non-aqueous solution redox analytes are used to probe the responsiveness.

Electrocatalysis. Diamond is being investigated as an advanced electrocatalyst support material, possibly for fuel cells. The factors that influence the nucleation, growth, and adhesion of metal catalyst nanoparticles (e.g., Pt) on the diamond electrode surface are being investigated. Pt/diamond and Pt/Ru/diamond composite electrodes are being prepared and evaluated for their catalytic performance using the oxygen reduction and methanol oxidation reactions. Diamond provides a thermally stable and corrosion resistant support/host, that is superior to commonly used sp2 carbon supports.

Spectroelectrochemistry. Three types of optically transparent diamond electrodes (OTE’s) are being developed for use in transmission spectro­electrochemical measurements: free­standing polished discs (UV/Vis/IR), films deposited on quartz (UV/Vis), and films deposited on Si (IR). The OTE’s are being used for chemical analysis (e.g. explosives) in the UV-Vis and for protein (e.g. cytochrome c) structure-function studies in the IR region of the electromagnetic spectrum. Long optical path length thin layer spectroelectrochemical measurements are also being used to study molecular adsorption on diamond electrodes.

Electroanalysis. Diamond possesses some excellent properties for electroanalysis (low background signal, excellent stability, resistance to fouling, good responsiveness without pretreatment). These electrodes are currently being used for electrochemical detection coupled with electrophoretic separations (both capillary column and microchip). Diamond offers performance advantages in terms of dynamic range, limit of detection, response precision, and response stability. Some of the analytes presently under study include amino acids, chlorinated phenols, pesticides, catecholamine neurotransmitters and their metabolites, and aliphatic polyamines (e.g., cadaverine).

Representative Publications:

  1. Fabrication and Evaluation of Platinum/Diamond Composite Electrodes for Electrocatalysis: Preliminary Studies of the Oxygen Reduction Reaction, J. Wang, and G. M. Swain, J. Electrochem. Soc., 150, E24 (2003).
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  2. Characterization and Electrochemical Responsiveness of Boron-Doped Nanocrystalline Diamond Thin-Film Electrodes, Y. Show, M. A. Witek, P. Sonthalia, and G. M. Swain, Chem. Mater., 15, 879 (2003).
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  3. Confocal Raman Imaging Study of an Optically Transparent Boron-Doped Diamond Electrode, M. Mermoux, B. Marcus, G. M. Swain, and J. E. Butler, J. Phys. Chem., 106, 10816 (2002).
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  4. Optical and Electrochemical Properties of Optically Transparent, Boron-Doped Diamond Thin Films Deposited on Quartz, J. Stotter, J. Zak, Z. Behler, Y. Show, and G. M. Swain, Anal. Chem., 74, 5924 (2002).
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  5. Direct Electrochemistry of Cytochrome c at Nanocrystalline Boron-Doped Diamond, S. Haymond, G. T. Babcock, and G. M. Swain, J. Amer. Chem. Soc., 124, 10634 (2002).




This page last updated August 6, 2003.