ATOMISTIC MODELING OF AN ELECTROCHEMICAL INTERFACE

Open Access
Author:
Glasspool, Michael Victor
Graduate Program:
Chemical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
May 24, 2011
Committee Members:
  • Michael John Janik, Thesis Advisor
  • Janna Kay Maranas, Thesis Advisor
Keywords:
  • Electrochemical Interfaces
Abstract:
Electrochemical interfaces are present in a variety of applications. Despite their prevalence, the electrode/electrolyte interface is not well understood from a molecular standpoint. Variations in the electrolyte structure near an electrode surface give rise to fluctuations in the electric field which can affect surface reaction kinetics. One device affected by such phenomena is the proton exchange membrane fuel cell (PEMFC). The cathode half of a PEMFC, at which the oxygen reduction reaction takes place, accounts for nearly 70% of the total performance losses during typical operation. Characterizing the interfacial structure at a PEMFC cathode can give insight into what causes these performance losses. In this study, we develop a new method to analyze an electrochemical system. Molecular dynamics simulations can be used to describe systems with atomistic detail, and explain macroscopic phenomena. Using the Central Force Model to describe liquid water, and Electrode Charge Dynamics to account for electronic polarizability in a platinum electrode, we will simulate the electrochemical interface in a manner than can produce a more accurate characterization of the interfacial structure. We use sulfuric acid in the electrolyte to approximate the behavior of the Nafion ® membrane used in PEM fuel cells. We describe sulfuric acid in a reactive manner by incorporating the acid into the Central Force Model.