Year: 2017
Type: dissertation
Abstract: Mass transport parameters are determined for the oxygen reduction reaction (ORR) at the electrochemical interface of a platinum microdisk electrode and five different series of polymer electrolyte membranes.The series included proton exchange polyfluorosulfonic acid (PFSA) based membranes (Nafion 117, Nafion 211), films cast from PFSA dispersions (DE2020), anion exchange quaternary ammonium based membranes (FAA-3), and films cast from hexamethyl-p-terphenyl polymethylbenzimidazole (HMT-PMBI) dispersions.The membranes differ in chemical structure, morphology, and water content controlled by relative humidity.The series of materials were investigated over a range of temperatures (50-70 °C) and relative humidities (30-98% RH) using a solid state electrochemical cell.Cyclic voltammetry yielded the potentials where ORR is mass transport limited, as well as the electrochemically active surface area of the platinum microdisk electrode.Chronoamperometry was performed at mass transport limiting potentials, where fitting the current transients to analytical models (Cottrell/Shoup-Szabo) allowed for the calculation of oxygen diffusion coefficient (D b ), solubility (c b ), and permeability (D b *c b ) for the applied environmental conditions.A numerical model is also presented which highlights constraints in using the analytical models to determine mass transport parameters when the inherently-assumed infinite electrolyte thickness is not present. DedicationTo my parents, Dave and Doreen Novitski for the support and guidance they have given me and the sacrifices they have made to ensure the best opportunity for their kids.To Emily for her endless encouragement and enthusiasm toward
Source: Summit (Simon Fraser University)
Author: David Novitski
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2743394878