Widtsoe Presidential Endowed Chair in Chemistry
B.S., University of North Carolina, 1978
Ph.D., University of Texas, 1983
Postdoctoral Associate, Massachusetts Institute of Technology, 1983-84
Phone: (801) 585-6256
Office: B423 TBBC
Activities & Awards
- Allen J. Bard Award, The Electrochemical Society, 2015
- Utah Governor's Medal for Science and Technology, 2014
- Fellow of the American Chemical Society, 2012
- Fellow of the American Association for the Advancement of Science, 2011
- Fellow of the American Academy of Arts & Sciences, 2011
- Carl Wagner Award, The Electrochemical Society, 2010
- American Chemical Society Utah Award, 2008
- W.W. Epstein Outstanding Educator Award, U of Utah, 2007
- David Grahame Award, The Electrochemical Society, 2005
- President, Society of Electroanalytical Chemistry, 2003-2005
- Associate Editor, Journal of the American Chemical Society
- ACS Analytical Division Award in Electrochemistry, 2004
- University of Utah Distinguished Research Award, 2004
- Students Choice Teaching Award, Associated Students of the U of Utah, 2003
- Faraday Medal, Royal Society of Chemistry, Electrochemical Section, London, 2002
- Chair, Gordon Research Conference on Electrochemistry, 2002
- Charles N. Reilley Award, The Society of Electroanalytical Chemistry, 2000
My colleagues and I are engaged in both experimental and theoretical aspects of electrochemistry, with diverse connections to analytical, biological, physical, and materials chemistry. Please see our group website for fuller project descriptions and links to recent publications.
Transport in Thin Layer Batteries. We are studying ion transport in batteries in which the anode and cathode is separated by a ultra-thin electrolyte layer (10s of nanometers wide). At this length scale, the electrical double layers that form at both the anode and cathode begin to overlap which results in changes in the molecular transport (diffusion and migration) of ions. We investigate this phenomenon both theoretical, using finite element simulations, and experimental, using nanometer-scale electrochemical cells.
Nanopore Analysis of DNA. The protein pore αHL has emerged as a powerful tool with which DNA can be analysed. While ssDNA can pass through the smallest constriction in αHL (1.4 nm), dsDNA, which has a nominal diameter of 2.0 nm, cannot. However, it is possible to capture dsDNA inside the α-HL vestibule and unzip it into its constituent single-stranded components. We have recently discovered that structural modifications in DNA in a duplex can also be detected from the magnitude to which ion flow is attenuated during dsDNA residence inside the protein pore. We are currently exploring uses of this sensing zone for identifying and discriminating damage sites in dsDNA.
Nanopore Physics. Ion transport in confined geometries is significantly different from bulk solutions. For example, ion current rectification (ICR) in nanopores is a phenomenon that arises due to the asymmetric charge distribution of the nanopores. Our group has discovered a number of interesting ion transport and fluid phenomena in nanopore systems, including negative differential electrolyte resistance in which a fluid bistability results in a decrease in current with increasing applied voltage.
Nanoparticle Analysis. We have developed an understanding of the dynamics of particles travelling through pores, the forces involved, and the various ionic contributions to the shape of the resistive pulse. This understanding has enabled us to develop a multipass resistive pulse method, where we switch the pressure/voltage to repeatedly pass individual nanoparticles back and forth through the orifice of a conical nanopore/nanopipette. This leads to a precisely determined mean blocking current equating to sub-nanometer particle size resolution. We are currently exploring controlled delivery of single particles & molecules to electrochemical interfaces.
Nanobubbles. Gas nanobubbles formed at solid/liquid interfaces have received significant attention during the past decade due to their remarkable properties. We have developed an electrochemical approach for investigating the formation and properties of single nanobubbles of H2, N2, CO2, or O2 using Pt disk electrodes radii between 5 and 50 nm. The nanobubble experiments reveal the nucleation mechanism of single nanobubble at the interface, as well as provide insight into the structure and chemical dynamics of electrochemical three-phase solid/liquid/gas boundaries.
Modeling Experimental Systems. For the systems investigated in the our group, the experimentally measured quantity is most typically the current, or a statistical measure derived from it, whereas our interest usually lies in the underlying physical and chemical phenomena. Interpretation of our data is typically underpinned by a theoretical model of the system, which may be an analytical expression or a numerical calculation, relating the measured quantity to one or more physical quantities. Typical problems include, for instance, relating electron-transfer rates with the local electrostatic potential distribution, computing the forces of a nanoparticle and its resulting velocity, or studying the effect of ion transport in confined spaces on the discharge rate of a 3D battery.
- Robert P. Johnson, Aaron M. Fleming, Rukshan T. Perera, Cynthia J. Burrows, Henry S. White, “The Dynamics of a DNA Mismatch Site Held in Confinement Discriminate Epigenetic Modifications to Cytosine,” J. Am. Chem. Soc., 2017, 139, 2750–2756.
- Yun Yu, Vignesh Sundaresan, Sabyasachi Bandyopadhyay, Yulun Zhang, Martin A. Edwards, Kim McKelvey, Henry S. White, and Katherine A. Willets, “Three-Dimensional Super-Resolution Imaging of Single Nanoparticles Delivered by Pipettes,” ACS Nano, 2017, 11, 10529–10538.
- Donald Robinson, Yuwen Liu, Martin Edwards, Nicholas Vitti, Stephen Oja, Bo Zhang, Henry S. White, "Collision Dynamics During the Electrooxidation of Individual Silver Nanoparticles," J. Am. Chem. Soc., 2017, 139,16923–1693.
- H. Ren, S. R. German, M. A. Edwards, Q. Chen, and H. S. White “Electrochemical Generation of Individual O2 Nanobubbles via H2O2 Oxidation,” J. Phys. Chem. Lett., 2017, 8, 2450-2454.
- Ruperto G. Mariano, Kim McKelvey, Henry S. White, Matthew W. Kanan, “Selective Increase in CO2 Electroreduction Activity at Grain Boundary Surface Terminations,” Science, 2017, 358, 1187.
- K. McKelvey, A. A. Talin, B. Dunn, and H. S. White, ”Microscale 2.5D Batteries,” Journal of The Electrochemical Society, 2017, 164, A2500-2503.
- H. S. White, K. McKelvey, “Redox Cycling in Nanogap Electrochemical Cells,” Current Opinion in Electrochemistry, 2018, 7, 48-53.
- Cherie S. Tan, Aaron M. Fleming , Hang Ren , Cynthia J. Burrows, and Henry S. White, “γ-Hemolysin Nanopore Is Sensitive to Guanine-to-Inosine Substitutions in Double-Stranded DNA at the Single-Molecule Level,” J. Am. Chem. Soc., 2018, 140, 14224–14234.
- Martin Edwards, Donald Robinson, Hang Ren, Cameron Cheyne, Cherie Tan, and Henry S. White, “Nanoscale electrochemical kinetics & dynamics: the challenges and opportunities of single-entity measurements,” Faraday Discuss., 2018, 210, 9-28.
- Álvaro Moreno Soto, Sean R. German, Hang Ren, Devaraj van der Meer, Detlef Lohse, Martin A. Edwards, and Henry S. White, “Critical Nuclei Size, Rate, and Activation Energy of H2 Gas Nucleation,” Langmuir, 2018, 34, 7309–7318.
- Hang Ren, Cameron G. Cheyne, Aaron M. Fleming, Cythia J. Burrows, and Henry S. White. “Single-Molecule Titration in a Protein Nanoreactor Reveals the Protonation/Deprotonation Mechanism of a C:C Mismatch in DNA,” J. Am. Chem. Soc., 2018, 140, 5153-5160.
- Donald Robinson, Martin A. Edwards, Hang Ren, and Henry S. White, “Effects of Instrumental Filters on Electrochemical Measurement of Single‐Nanoparticle Collision Dynamics,” ChemElectroChem,2018,5, 3059-3067.
- Kim McKelvey, Donald A. Robinson, Nicholas J. Vitti, Martin A. Edwards, Henry S. White, “Single Ag nanoparticle collisions within a dual-electrode micro-gap cell,” Faraday Discuss., 2018, 210, 189-200.
- Sean R. German, Martin A. Edwards, Hang Ren, Henry S. White, “Critical Nuclei Size, Rate, and Activation Energy of H2 Gas Nucleation,” J. Am. Chem. Soc., 2018, 140, 4047–4053.
- Xianchan Li, Lin Ren, Johan Dunevall, Daixin Ye, Henry S. White, Martin A. Edwards, and Andrew G. Ewing, “On the Nanopore Opening at Flat and Nano-Tip Conical Electrodes during Vesicle Impact Electrochemical Cytometry,” ACS Nano, 2018, 12, 3010–3019.