|Multiple Reaction Pathways for the Oxygen Evolution Reaction May Contribute to IrO2 (110)'s High Activity
|Year of Publication
|Ha M-A, Larsen RE
|Journal of The Electrochemical Society
|DFT modeling, Iridium oxide, Oxygen evolution
Density functional theory calculations in conjunction with statistical mechanical arguments are performed on the rutile IrO2 (110) facet in order to characterize multiple reaction pathways on the surface at the highest active limit (the stoichiometric surface with all metal sites available) and at the lowest active limit (the oxygen-terminated surface). Alternative pathways to the oxygen evolution reaction (OER) are found, with multiple pathways determined at each step of the four proton-coupled electron transfer reaction. Of particular interest is the detailed characterization of a co-adsorption pathway utilizing neighboring, adsorbed O, OH species in order to evolve oxygen; activation energies of this pathway are <0.5 eV and therefore easily surmountable at the high operating potentials of OER. We also determined that surface Ir atoms can potentially participate in deprotonating an OOH* intermediate; the activation energy to this is 0.67 eV on the oxygen-terminated surface. These theoretical findings explain in part the high activity present in iridium oxide catalysts and also provide insight into the mechanistic pathways available on metal oxide catalysts, which may require the concerted interaction of nearest neighbor co-adsorbates to produce chemicals of interest.
Multiple Reaction Pathways for the Oxygen Evolution Reaction May Contribute to IrO2 (110)'s High Activity
Submitted by nnguyen2 on Fri, 05/13/2022 - 09:34