|
Activities & Awards
Grahame Award of the Electrochemical Society, 2005
ACS Analytical Division Award in Electrochemistry, 2004
University of Utah, Distinguished Research Award, 2004
Faraday Medal, Royal Society of Chemistry,
London, 2002
Reilley Award of the Society of Electroanalytical Chemistry, 2000
Shell Chair of Chemical Engineering and Materials Science, University
of Minnesota, 1992
Associate Editor, Journal of the American Chemical Society President, Society of Electroanalytical Chemistry, 2003-05
Research Interests
My colleagues and I are engaged in both experimental and theoretical aspects of electrochemistry, with diverse connections to analytical, biological, physical, and materials chemistry. Much of our current research is focused on electrochemistry in microscale and nanoscale domains.
Electrochemistry in Nanoscale Domains.
Methods of electrode fabrication are being developed that allow voltammetric analyses of very small numbers of molecules. We have also recently developed the "nanopore electrode", a Pt disk electrode embedded at the bottom of a conical shaped pore, the circular orifice of the pore having nanometer dimensions. The steady-state flux of molecules to this electrode is limited by transport through the orifice, a very useful characteristic in studying transport in nanometer-diameter pores. Chemical modification of the pore walls introduces chemical-selective transport for sensing applications.
|
|
Coulomb Transport in Ultrathin-Layer Electrochemical Cells.
Investigations of electrochemical cells comprising two electrodes separated by ultra-thin (~10 nm) layers of electrolyte have demonstrated that overlap of the electrical double layers results in molecular transport being driven by the surface charge of the electrodes, a phenomenon we refer to as "coulomb transport." The influence of coulomb transport on the characteristics of nanometer-scale electrochemical cells is being investigated for applications in batteries and chemical sensors.
Iontophoretic Transport Through Skin. Electric field-induced molecular transport through human skin is currently being investigated as a means of drug administration. Human skin is a very complex, heterogeneous membrane, and molecular transport through it is poorly characterized. Our current effort focuses on developing experimental methods to determine the physiological structures in skin that act as molecular transport pathways. Scanning electrochemical microscopy has been developed in our laboratory to visualize molecular transport in biological membranes.
Magnetic Field Effects on Electrochemical Reactions . Measurements are made using ultramicroelectrodes to enhance the Lorentzian and gradient forces that developed at the electrode/electrolyte interface during electron-transfer processes. Solution-phase ion-trapping and focusing techniques for analytical applications are also being developed.
Selected Publications
- B. Zhang, Y. Zhang, and H. S. White, "The Nanopore Electrode," Anal. Chem. , in press.
J. J. Watkins, B. Zhang, and Henry S. White, "Electrochemistry at Nanometer-Scale Electrodes," J. Chem. Ed ., in press.
- M. R. Newton, K. A. Morey, Y. Zhang, R. Snow, M. Diwekar, J. Shi, and H. S. White, "Anisotropic Diffusion in Face-Centered Cubic Opals," Nano Letters 2004 , 4, 875.
- C. J. Boxley and H. S. White, "Studies of the Relationship Between the Rate of Al 2 O 3 Film Dissolution and the Pitting Potential of Aluminum in Aqueous Chloride Solution" J. Electrochem. Soc. 2004 , 151 , B265.
- S. Lee, Y. Zhang, Henry S. White, C. C. Harrell and C. R. Martin "Electrophoretic Capture and Detection of Nanoparticles at the Opening of a Membrane Pore using Scanning Electrochemical Microscopy," Anal. Chem. , in press.
- J. J. Watkins and H. S. White, "The Role of the Electrical Double-Layer and Ion Pairing on the Electrochemical Oxidation of Hexachloroiridate(III) at Pt Electrodes of Nanometer Dimensions," Langmuir 2004 , 20, 5474.
- J. J. Watkins, J. Chen, H. S. White, E. Maisonhaute and C. Amatore, "Zeptomole Voltammetric Detection and Electron-Transfer Rate Measurements Using Platinum Electrodes of Nanometer Dimensions," Anal. Chem . 2003 , 75, 3962.
- K.M. Grant, J.W. Hemmert, and H.S. White, "Magnetic Field Controlled Microfluidic Transport," J. Am. Chem. Soc. 2002 124 , 462.
|
