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Title: Structure Sensitivity of Methanol Electrooxidation on Transition Metals

Abstract

We have investigated the structure sensitivity of methanol electrooxidation on eight transition metals (Au, Ag, Cu, Pt, Pd, Ir, Rh, and Ni) using periodic, self-consistent density functional theory (DFTGGA). Using the adsorption energies of 16 intermediates on two different facets of these eight face-centeredcubic transition metals, combined with a simple electrochemical model, we address the differences in the reaction mechanism between the (111) and (100) facets of these metals. We investigate two separate mechanisms for methanol electrooxidation: one going through a CO* intermediate (the indirect pathway) and another that oxidizes methanol directly to CO2 without CO* as an intermediate (the direct pathway). A comparison of our results for the (111) and (100) surfaces explains the origin of methanol electrooxidation’s experimentally-established structure sensitivity on Pt surfaces. For most metals studied, on both the (111) and (100) facets, we predict that the indirect mechanism has a higher onset potential than the direct mechanism. Ni(111), Au(100), and Au(111) are the cases where the direct and indirect mechanisms have the same onset potential. For the direct mechanism, Rh, Ir, and Ni show a lower onset potential on the (111) facet, whereas Pt, Cu, Ag, and Au possess lower onset potential on the (100) facet.more » Pd(100) and Pd(111) have the same onset potential for the direct mechanism. These results can be rationalized by the stronger binding energy of adsorbates on the (100) facet versus the (111) facet. Using linear scaling relations, we establish reactivity descriptors for the (100) surface similar to those recently developed for the (111) surface; the free energies of adsorbed CO* and OH* can describe methanol electrooxidation trends on various metal surfaces reasonably well.« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1001521
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 131; Journal Issue: 40; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
10 SYNTHETIC FUELS; ADSORPTION; BINDING ENERGY; FCC LATTICES; FUNCTIONALS; METHANOL; ORIGIN; REACTION KINETICS; SENSITIVITY; TRANSITION ELEMENTS; Environmental Molecular Sciences Laboratory

Citation Formats

Ferrin, Peter A, and Mavrikakis, Manos. Structure Sensitivity of Methanol Electrooxidation on Transition Metals. United States: N. p., 2009. Web. doi:10.1021/ja904010u.
Ferrin, Peter A, & Mavrikakis, Manos. Structure Sensitivity of Methanol Electrooxidation on Transition Metals. United States. https://doi.org/10.1021/ja904010u
Ferrin, Peter A, and Mavrikakis, Manos. 2009. "Structure Sensitivity of Methanol Electrooxidation on Transition Metals". United States. https://doi.org/10.1021/ja904010u.
@article{osti_1001521,
title = {Structure Sensitivity of Methanol Electrooxidation on Transition Metals},
author = {Ferrin, Peter A and Mavrikakis, Manos},
abstractNote = {We have investigated the structure sensitivity of methanol electrooxidation on eight transition metals (Au, Ag, Cu, Pt, Pd, Ir, Rh, and Ni) using periodic, self-consistent density functional theory (DFTGGA). Using the adsorption energies of 16 intermediates on two different facets of these eight face-centeredcubic transition metals, combined with a simple electrochemical model, we address the differences in the reaction mechanism between the (111) and (100) facets of these metals. We investigate two separate mechanisms for methanol electrooxidation: one going through a CO* intermediate (the indirect pathway) and another that oxidizes methanol directly to CO2 without CO* as an intermediate (the direct pathway). A comparison of our results for the (111) and (100) surfaces explains the origin of methanol electrooxidation’s experimentally-established structure sensitivity on Pt surfaces. For most metals studied, on both the (111) and (100) facets, we predict that the indirect mechanism has a higher onset potential than the direct mechanism. Ni(111), Au(100), and Au(111) are the cases where the direct and indirect mechanisms have the same onset potential. For the direct mechanism, Rh, Ir, and Ni show a lower onset potential on the (111) facet, whereas Pt, Cu, Ag, and Au possess lower onset potential on the (100) facet. Pd(100) and Pd(111) have the same onset potential for the direct mechanism. These results can be rationalized by the stronger binding energy of adsorbates on the (100) facet versus the (111) facet. Using linear scaling relations, we establish reactivity descriptors for the (100) surface similar to those recently developed for the (111) surface; the free energies of adsorbed CO* and OH* can describe methanol electrooxidation trends on various metal surfaces reasonably well.},
doi = {10.1021/ja904010u},
url = {https://www.osti.gov/biblio/1001521}, journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 40,
volume = 131,
place = {United States},
year = {Wed Oct 14 00:00:00 EDT 2009},
month = {Wed Oct 14 00:00:00 EDT 2009}
}