462588 Oxyhydroxides As a Platform for Confined Oxygen Electrochemistry

Tuesday, November 15, 2016: 9:30 AM
Franciscan C (Hilton San Francisco Union Square)
Andrew Doyle, Chemical Engineering, Stanford University, Stanford, CA, Michal Bajdich, Department of Chemical Engineering, SUNCAT Center for Interface Science and Catalysis, Stanford University and SLAC National Accelerator Laboratory, Stanford, CA and Aleksandra Vojvodic, SLAC National Accelerator Laboratory/Stanford University, Menlo Park, CA

Oxyhydroxides as a Platform for Confined Oxygen Electrochemistry
Authors: Andrew D. Doyle, Michal Bajdich, Aleksandra Vojvodic

As we move towards fossil-free electrification a number of strong renewable energy technologies have emerged. However, some promising candidates (notably solar and wind power) provide only intermittent energy generation, which cannot immediately meet the total demand on a national scale. One proposed solution is to stabilize these renewable sources by coupling to external energy storage, including regenerative fuel cells which convert energy between electricity and the chemical bonds in water, oxygen, and hydrogen.

Unfortunately, researchers have shown that the catalytic efficiency of regenerative fuel cell technology is fundamentally limited by energetic scaling between reaction intermediates [1], [2]. However, our recent results have demonstrated that nanoscale channels may circumvent this scaling, and in the process allow for higher efficiency devices [3].

Additionally, experimental work has shown that doped NiOOH and similarly-structured materials have promise as possible next-generation catalysts for oxygen electrochemistry (water oxidation and oxygen reduction), possibly due to their unique crystal structure [4], [5].

In this work we will present results from density functional theory (DFT) calculations to explore NiOOH as a natural template for sub-nanometer channel formation with particular emphasis on the activity of bulk-like sites towards the oxygen evolution reaction. We will discuss the energetics of binding between hydroxide layers (relative to the surface), the impact of iron doping, and the possibility that subsurface activity contributes to the measured activity.

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[2] V. Viswanathan, H. A. Hansen, J. Rossmeisl, and J. K. Nørskov, “Universality in Oxygen Reduction Electrocatalysis on Metal Surfaces,” ACS Catal., vol. 2, no. 8, pp. 1654–1660, Aug. 2012.

[3] A. D. Doyle, J. H. Montoya, and A. Vojvodic, “Improving Oxygen Electrochemistry through Nanoscopic Confinement,” ChemCatChem, vol. 94025, 2015.

[4] M. S. Burke, S. Zou, L. J. Enman, J. E. Kellon, C. a Gabor, E. Pledger, and S. W. Boettcher, “Revised Oxygen Evolution Reaction Activity Trends for First-Row Transition-Metal (Oxy)hydroxides in Alkaline Media,” 2015.

[5] K. Klingan, F. Ringleb, I. Zaharieva, J. Heidkamp, P. Chernev, D. Gonzalez-Flores, M. Risch, A. Fischer, and H. Dau, “Water oxidation by amorphous cobalt-based oxides: Volume activity and proton transfer to electrolyte bases,” ChemSusChem, vol. 7, no. 5, pp. 1301–1310, 2014.

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