Advancing Nanoelectrochemical Measurements

Professor Martin Edwards, University of Arkansas

Nanoelectrochemical tools, such as electrochemical microscopes, nanopore sensing, and nanoelectrodes, can address questions that are inaccessible to macroscale techniques. They allow one to measure faster processes and shorter-lived species, assess spatial heterogeneity of electrode surfaces, and by measuring individual nanoscale entities (e.g., nanoparticles), assess heterogeneity in a population. This has led to a deeper understanding of both electrochemical processes (e.g., electrocatalysis) and physical processes (e.g., nucleation).

Yet despite these advances, key experiments from the macroscale electroanalytical toolbox are presently inaccessible or infeasible at the nanoscale. For example, it is not feasible to characterize individual nanoentities or nanoscale regions with multiple solutions with a statistically relevant throughput. Yet, changing the solution composition is a powerful and commonly applied strategy with numerous applications. For example, one might decipher a reaction mechanism by measuring at different pHs, adding reaction intermediates, or inhibitors. Alternatively, one might electrodeposit an electrocatalyst and then characterize it in a different solution, studying how deposition parameters influence activity. Or more simply, one might wish to perform a background measurement and then measure at different analyte concentrations to deliver background subtracted current-concentration responses. This talk will describe our efforts to address this limitation through development of a species-switching scanning electrochemical microscope capable of measuring single nanoscale regions and entities under multiple solution conditions. 

Biography

Martin Edwards joined the University of Arkansas, Fayetteville, as an assistant professor of analytical chemistry in 2020. His group’s research combines physical/analytical techniques with mathematical modeling to understand and manipulate diverse micro- and nanoscale physical and chemical phenomena. Using an approach that combines physical and analytical measurements with modeling (mathematical/statistical/numerical), he has tackled problems and answered questions in areas ranging from single-molecule bioanalytical measurements, through next-generation energy-storage technologies, nucleation, and electrocatalysis. A constant thread throughout his research is the development of novel instrumentation, experiments, and the frameworks for interpreting them. His work frequently involves the development or modification of scanned probe microscopes. He is the co-inventor of the scanning electrochemical cell microscope, which is now used in >50 labs worldwide. He was the 2020 recipient of the Royce Murray Young Investigator award from the Society of Electroanalytical Chemistry (SEAC). His works have been supported by an NSF CAREER award, a Society of Analytical Chemists of Pittsburgh Starter Grant, and by the US Army Engineer Research and Development Center.

Prof. Edwards has a highly interdisciplinary background, which began with a Master's of Mathematics (MMath, 2003), followed by an MSc (Mathematical Biology and Biophysical Chemistry, 2004) and PhD (Development of Electrochemical Probe Microscopy and Related Techniques, supervisors Patrick R. Unwin and Anna L. Whitworth 2009), all from the University of Warwick (UK). Subsequently, he performed postdoctoral studies at the Catalan Institute for Bioengineering (IBEC), Barcelona (Electrical Scanning Probe Microscopy for Microbiology; supervisors Profs Gabriel Gomila and Antonio Juárez) and The University of North Carolina at Chapel Hill (Development of Electrochemical Techniques for Neuroscience Applications, Prof. R. Mark Wightman). From 2014-2020 he was a research professor in the group of Henry White in the Department of Chemistry at the University of Utah.