2020 Virtual AIChE Annual Meeting

(372f) Mechanistic Understanding of Electrochemical Processes in Alkaline Environments

Authors

Schimmenti, R. - Presenter, University of Wisconsin-Madison
Murray, E. A., University of Wisconsin-Madison
Mavrikakis, M., University of Wisconsin - Madison
Alkaline fuel cells (FCs) have attracted attention for potential applications in efficient energy production. The higher stability of non-precious metals in alkaline environment offers the possibility to synthesize cheaper electrocatalysts, lowering the overall cost of FCs [1]. However, non-precious metal anodic electrocatalysts are considerably less active than more commonly used PGM-electrocatalysts. As a result, successful wide-scale development of high-performance alkaline precious metal-free FC remains a challenge.

Mechanistic understanding of electrocatalytic processes could greatly contribute to the design of improved electrocatalysts. At present, comprehensive mechanistic models capable of capturing the in situ nature of the catalytic active site in alkaline environment are still lacking for cases such as the oxygen reduction reaction (ORR) and the ammonia oxidation reaction (AOR).

In this contribution, we utilize electronic-structure calculations in the framework of coverage-cognizant DFT models to unravel complex reaction mechanisms for ORR and AOR in alkaline environment. We will focus on ORR on Au(100) and AOR on Pt(111), with two key questions in mind: i. “What is the origin of the remarkable activity of Au(100) for ORR in alkaline environment?”[2] and ii. “What is source of Pt deactivation in the AOR?”[3-6].

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[4] Matsui T., Suzuki S., Katayama Y., Yamauchi K., Okanishi T., Muroyama H., Eguchi K., Langmuir, 31, 11717–11723 (2015)

[5] Vidal-Iglesia F. J., Solla-Gullón J., Pérez J. M., Aldaz A., Electrochem. Commun., 8, 102–106 (2006)

[6] Herron J. A., Ferrin P., Mavrikakis M., J. Phys. Chem. C, 119, 14692–14701 (2015)