(205d) Impact of Intrinsic Surface Strain on Electrocatalytic Processes

Authors: 
Greeley, J., Purdue University
Zeng, Z., Purdue University
Wang, C., Johns Hopkins University
Wang, L., Johns Hopkins University
Advances in the theoretical understanding of interfacial electrochemistry have, over the past decade, permitted the extension of periodic Density Functional Theory studies, which have traditionally been applied to probe chemistry at gas/solid interfaces, to electrochemical systems where potential-dependent reactions occur at liquid/solid interfaces. Indeed, such techniques have been employed to study a surprisingly wide range of chemical processes, from electrochemical oxygen reduction to carbon dioxide reduction to water splitting. These advances have, in turn, opened new possibilities for correlating fundamental surface properties of electrocatalysts with corresponding reactivity trends.

In this talk, I will briefly review the theory of how surface strain, a ubiquitous phenomenon in both traditional heterogeneous catalysis and electrocatalysis, impacts surface catalytic reactions and how this phenomenon has been exploited, in particular, to design and optimize oxygen reduction reaction electrocatalysts. I will argue that, in all such catalysts developed to date, strain effects have been convoluted with other phenomena such as alloying, substrate, and coordination effects. I will then discuss a class of quasi-two dimensional transition metal electrocatalysts, recently developed in our team, that avoids these complications and exhibits an essentially pure strain effect. The resulting structures function as highly active ORR electrocatalysts in alkaline conditions. Finally, if time permits, I will discuss how such principles may be extended to the analysis of other electrocatalytic chemistries, such as electroreduction of nitrogen-containing oxides on precious metal surfaces.

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