Proton-coupled electron transfer at SOFC electrodes.

Autor:	Williams NJ; Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA., Warburton RE; Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA., Seymour ID; Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom., Cohen AE; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA., Bazant MZ; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.; Department of Mathematics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA., Skinner SJ; Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
Jazyk:	angličtina
Zdroj:	The Journal of chemical physics [J Chem Phys] 2023 Jun 28; Vol. 158 (24).
DOI:	10.1063/5.0145247
Abstrakt:	Understanding the charge transfer processes at solid oxide fuel cell (SOFC) electrodes is critical to designing more efficient and robust materials. Activation losses at SOFC electrodes have been widely attributed to the ambipolar migration of charges at the mixed ionic-electronic conductor-gas interface. Empirical Butler-Volmer kinetics based on the transition state theory is often used to model the current-voltage relationship, where charged particles transfer classically over an energy barrier. However, the hydrogen oxidation/water electrolysis reaction H2(g) + O2- ⇌ H2O(g) + 2e- must be modeled through concerted electron and proton tunneling events, where we unify the theory of the electrostatic surface potential with proton-coupled electron transfer kinetics. We derive a framework for the reaction rate that depends on the electrostatic surface potential, adsorbate dipole moment, the electronic structure of the electron donor/acceptor, and vibronic states of the hydrogen species. This theory was used to study the current-voltage characteristics of the Ni/gadolinium-doped ceria electrode in H2/H2O(g), where we find excellent validation of this novel model. These results yield the first reported quantification of the solvent reorganization energy for an SOFC material and suggest that the three-phase boundary mechanism is the dominant pathway for charge transfer at cermet electrodes. (© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)
Databáze:	MEDLINE
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