(Physical and Analytical Electrochemistry Division David C. Grahame Award) My 54 Years of Doing Electrochemistry and What Is New

Abstract

I am very honored to be selected to receive the David C. Graham Award from the Electrochemical Society, an award that has been bestowed on so many outstanding electrochemists over the years including many of my mentors. This symposium is also close to my 70th birthday and may then be near the end of attending ECS meetings. My talk will start with an acknowledgement that awards like this do not happen without the students, post docs and colleagues that have worked for me and with me over my 54 years of doing electrochemistry that started with science fairs in high school and is ending at the University of Wyoming. Ironically the first papers that I read when arriving in graduate school at Caltech were David Graham’s pioneering work on double layers at mercury electrodes that were very relevant to part of my PhD work on double layer effects on electron transfer kinetics at mercury electrodes. My post doc at Bell Labs introduced me to solid state science and semiconductor photoelectrochemistry as applied to solar energy conversion. These topics continued to interest me for the rest of my career in photoelectrochemistry but I was always interested in learning new things and attacking interesting problems and I will briefly review some of this work. These include research in the areas of UHV surface science, both developing and applying scanning probe microscopies, growth and applications of 2D materials (long before they became a trend) and even photoelectrochemical processes on the surface of Mars where we explained the photoelectrochemical origin of the high concentrations of perchlorate on the surface of Mars.The rest of the talk will be concerned with an entirely new area for me, covalent organic framework (COF) materials applied to membranes applications, that has been a focus for the last few years. In this new project, a collaboration with colleagues at the University of Wyoming, involves developing two dimensional COFs with controllable sized hexagonal pores that we can functionalize with a wide variety of functional groups. We have been exploring applications of membranes constructed from these 2D-COFs for ion sieving based on size and charge, organic solvent separation and their antifouling abilities. Specifically, we have designed and tested a membrane constructed for a 2D-COF with pores that are lined with carboxylate groups that demonstrates a very specific size cut off for the conduction of a series of increasing sized tetraalkylammonium cations when paired with a polymeric anion that will not pass through the membrane. The stucture of this family of 2D-COFs is shown in the Figure. We have also demonstrated very high fluxes for organic solvent nanofiltration that is related to their polarity, size and hydrogen bonding properties. A future focus will be on developing a membrane that excludes small ions that will be useful in desalinization systems. Figure 1