Towards first-principles electrochemistry

This doctoral dissertation presents a comprehensive computational approach to describe quantum mechanical systems embedded in complex ionic media, primarily focusing on the first-principles representation of catalytic electrodes under electrochemical conditions. The accurate electrostatic description of electrified metal-solution interfaces represents a persistent challenge for ab-initio simulations and an essential requisite for predicting the electrical response of electrochemical convertors-i.e., the correspondence between the macroscopic voltage and the microscopic interfacial charge distribution. The approach consists of controlling the electrode voltage via its conjugate extensive variable, namely, the charge of the system. As a preliminary to the study of electrified interfaces in ionic media, we analyze charged slabs in vacuum subject to periodic boundary conditions. We show that the corrective potential (defined as the difference between the exact open-boundary potential and the periodic potential obtained from a Fourier transform) varies smoothly over space, allowing for its determination on a coarse mesh using optimized electrostatic solvers. Because this scheme takes into account exact open boundary conditions, its performance is considerably superior to that of conventional corrective methods. Extending this computational scheme, we present an efficient approach to model electrochemical systems under realistic conditions, based on a first-principles description of the interface region and on a continuum representation of the ionic solvent.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Dabo, Ismaila

Advisor dc:contributor.advisor

• Nicola Marzari.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/44320

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/44320