Ezra L. Clark

Assistant Professor

Penn State University

Electrocatalysis enables chemical transformations to be directly driven by renewable electricity, providing a viable route toward reducing the environmental impact of the chemical industry. The implementation of electrocatalytic technologies relies on the development of earth-abundant electrocatalysts with high intrinsic activity. Intrinsic activity is the ratio of the steady state surface coverage of reaction intermediates and their surface lifetimes. Unfortunately, no method currently exists for measuring either of these critical parameters. However, these parameters are routinely measured in thermal catalytic science using steady state isotopic transient kinetic analysis (SSITKA). SSITKA measurements are performed by reaching steady state in a catalytic reactor and then rapidly changing the isotopic composition of the reacting species. The catalyst surface is covered by reaction intermediates derived from the initial reactant at the moment of this isotopic switch. The steady state surface coverage of these intermediates is measured by quantifying the total number of product molecules evolved from the catalyst surface with the initial reactant isotopic composition after the switch has been performed. Additionally, the surface lifetimes of these species are quantified by fitting the decaying rate of formation of the corresponding product to an exponential function. While SSITKA has been performed for thermal catalytic systems for decades, it has never been performed for electrocatalytic systems due to the significant challenges of rapidly and quantitatively sampling electrochemical reaction products from the electrolyte. The first half of this presentation will describe our efforts to perform electrochemical SSITKA (eSSITKA) for the first time. The second half of this presentation will describe our efforts to develop superior electrocatalysts based on intermetallic alloying. The exceptionally strong heteronuclear bonds characteristic of these alloys enables systematic and independent control over surface reactivity and near-surface electric field strength under applied bias.

Dr. Ezra Clark received his BS in Chemical Engineering from the University of Louisville and his PhD in Chemical and Biomolecular Engineering from the University of California Berkeley. As part of our ongoing graduate student professional development series, Ezra will spend part of his talk discussing the transition from Graduate Student to Faculty Member and how to navigate that successfully.