Electrocatalysis enables chemical transformations to be directly driven by renewable electricity, providing a viable route toward reducing the environmental impact of the chemical industry. This presentation will begin by drawing parallels between thermal and electrocatalytic processes, with the goal of identifying scenarios when the catalytic activity an earth-abundant material can be significantly enhanced by incorporation into an electrochemical device. Unfortunately, many electrocatalytic processes rely on the use of expensive and scarce Pt-group metals. Thus, there is a significant need to develop electrocatalytic materials with lower precious metal content. The second chapter of this presentation will explore the use of intermetallic materials to satisfy this need. Intermetallics are a type of alloy that forms between electronically dissimilar metals. This electronic dissimilarity results in the formation of strong heteronuclear bonds that significantly modify the electronic properties and surface reactivities of the constituent metals. An electrochemical method for preparing these alloys will be introduced that enhances the intrinsic activity of precious metal electrocatalysts by roughly an order of magnitude. Intrinsic activity is the ratio of the steady state surface coverage of reaction intermediates and their surface lifetimes. Thus, such intrinsic activity promotion can be achieved by either enhancing the steady state coverage of reaction intermediates, reducing their surface lifetimes, or some combination thereof. Unfortunately, no method currently exists for measuring either of these critical parameters. This knowledge gap is significantly hindering the development of superior electrocatalysts by obscuring the origins of electrocatalytic activity promotion. This presentation will conclude by introducing an electrochemical isotopic transient measurement that is able to directly quantify these critical activity parameters for the first time. This measurement is performed by reaching steady state in the electrocatalytic reactor and then rapidly changing the isotopic composition of the reacting species. The electrocatalyst surface is covered by reaction intermediates derived from the initial reactant at the moment of this isotopic switch.
Ezra L. Clark is the Thomas K. Hepler Early Career Professor of Chemical Engineering at the Pennsylvania State University. His research group focus on the development of electrocatalytic technologies for sustainable fuel and chemical production. Currently, his group is focused on the development of electrochemical isotopic transient measurements, the design of intermetallic electrocatalysts, and the exploration of thermo-electrocatalytic synergy. Ezra earned his undergraduate degree in Chemical Engineering from the University of Louisville and his doctoral degree in Chemical Engineering from the University of California at Berkeley. Before arriving at Penn State, he performed postdoctoral research at the Danish Technical University outside of Copenhagen, Denmark. He has received numerous recognitions at every stage of his career, including a Goldwater Scholarship, a National Science Foundation Graduate Research Fellowship, a Marie Skłodowska-Curie Postdoctoral Research Fellowship, and the Hepler endowed professorship. He is also the president-elect of the Pittsburgh-Cleveland Catalysis Society (PCCS).