THEORETICAL PREDICTIONS OF POTENTIALS FOR INTERMEDIATE STEPS IN METHANOL AND ETHANOL ELECTROCHEMICAL OXIDATION ON Pt(111)

The elementary steps of methanol and ethanol electrochemical oxidation on Pt(111) were investigated using quantum mechanics theory. The reversible potential for each electron-transfer step and the reaction energy for non-electron transfer steps were calculated in bulk solution using Interface 1.0. This density functional theory (DFT) code uses modified Poisson-Boltzmann theory (MPB) and the dielectric continuum model to model the solvent, and allows adding or subtracting electronic charge to the solute or the surface with considering electrolyte response. Adsorption energies for reaction intermediates were calculated and used along with reversible potentials in bulk solution to predict surface reaction reversible potentials using linear Gibbs energy relationship model (LGER). This theory is capable of predicting approximate reversible potentials of redox reactions at solid-liquid interfaces by perturbing reversible potentials in bulk solution by internal energies of adsorption. Results were analyzed and compared with available experimental data and oxidation mechanisms were proposed. The accuracy of LGER was tested by comparing reversible potential of CO reduction to formyl on Pt(111) with the one obtained by a more accurate method, the Gibbs energy curve crossing procedure. The results confirm the reliability of LGER in predicting reversible potentials for surface reactions. The Gibbs energy curve crossing procedure was also applied in predicting the cyclic voltammogram of underpotential deposited hydrogen Hupd on Pt (111). The predicted CV showed good agreement with experiment.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

Case Western Reserve University School of Graduate Studies

Year dc:date

2013

Author dc:creator

• ASIRI, HALEEMA AIED

Contributors dc:contributor

• Anderson, Alfred
• Burda, Clemens

• Chemistry
• Energy

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=case1364831283

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1364831283