Electrocatalysts for voltage reversal tolerant anodes in proton exchange membrane fuel cells and CO2 reduction to formate
department or school: Applied Science, Faculty of
department or school: Chemical and Biological Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Moore, Colin E.
issued: 2019-11-25T17:06:01Z
issued: 2019
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Catalyst durability in renewable energy systems (including CO₂ electroreduction and Hydrogen fuel cells) is vital to the overall lifetime of the systems. To protect hydrogen fuel cells during cell voltage reversal, oxygen evolution reaction (OER) catalysts (typically RuO₂ or IrO₂) are added to the anode of proton exchange membrane fuel cells (PEMFCs). In this thesis, the durability of these OER catalysts was investigated by measuring the mass changes of heat-treated IrOx powders (350, 450 and 550 °C) drop cast on an electrochemical quartz crystal microbalance (EQCM). IrOx catalysts showed difference in frequency response due to the differential uptake of water and formation of oxyhydroxide species during cyclic voltammetry (CV) experiments (1.2, 1.4 and 1.6 to 0.05 V vs. RHE) confirmed by XPS. Platinum on carbon catalyst (Pt/C) suffered from carbon corrosion during potential holds at 1.8 and 2.0 V. The addition of IrOx powders to Pt/C protected the layer against carbon corrosion creating a simulated reversal tolerant anode. Additionally, OER catalysts were ranked by OER activity and dissolved Ir³⁺ in the electrolyte after an ex situ accelerated stress test (AST) in a representative PEMFC anode environment. The ex situ results are compared with reversal times obtained in a single cell PEMFC subjected to anode accelerated stress test (AAST). Generally, catalysts with higher OER mass activity and Ir³⁺ dissolution had longer reversal times. Heat treatment of unsupported IrOx increased OER durability in the fuel cell anode environment. Catalyst instability strongly affects the viability of electroreduction of CO₂ (ERC) systems as well. To improve the durability and efficiency of ERC catalysts, five Bimetallic Sn-Pb catalyst compositions were electrodeposited (from fluoroborate or oxide media) on two carbon supports. Sn majority catalysts with 15 to 35% Pb generated stable faradaic efficiencies (FE) up to 95% during constant potential electrolysis whereas pure Sn experien…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/72401
note: ELECTROCATALYSTS FOR VOLTAGE REVERSAL TOLERANT ANODES IN PROTON EXCHANGE MEMBRANE FUEL CELLS AND CO2 REDUCTION TO FORMATE by Colin E. Moore B.Sc., The University of North Carolina at Chapel Hill, 2009 M.Sc., Eötvös Loránd University, Budapest, Hungary, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Chemical and Biological Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) November 2019 © Colin E. Moore, 2019 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: ELECTROCATALYSTS FOR VOLTAGE REVERSAL TOLERANT ANODES IN PROTON EXCHANGE MEMBRANE FUEL CELLS AND CO2 REDUCTION TO FORMATE submitted by Colin E. Moore in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical and Biological Engineering Examining Committee: Elöd Gyenge Supervisor Natalia Kremliakova Supervisory Committee Member David Wilkinson Supervisory Committee Member Saavas Hatzikiriakos University Examiner Michael Wolf University Examiner Additional Supervisory Committee Members: Kevin Smith Supervisory Committee Member Supervisory Committee Member iii Abstract Catalyst durability in renewable energy systems (including CO2 electroreduction and Hydrogen fuel cells) is vital to the overall lifetime of the systems. To protect hydrogen fuel cells during cell voltage reversal, oxygen evolution reaction (OER) catalysts (typically RuO2 or IrO2) are added to the anode of proton exchange membrane fuel cells (PEMFCs). In this thesis, the durability of these OER catalysts was investigated by measuring the mass changes of heat-treated IrOx powders (350, 450 and 550 °C) drop cast on an electrochemical quartz crystal microbalance (EQCM). IrOx catalysts showed difference in frequency response due to the differential uptake of water and formation of oxyhyd…
has type: Thesis/Dissertation
date issued: 2020-05
is shown at: 10.14288/1.0385882
language: eng
degree discipline: Chemical and Biological Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/72401