Ghadge, Shrinath Dattatray
(2021)
A Fundamental Study of Electrocatalysts for Acid Mediated Electrochemical- Photoelectrochemical Water Splitting and Hydrogen Fuel Cell.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Rapid depletion of fossil fuels juxtaposed with deleterious effects of greenhouse gas emissions on global warming have provided a tremendous impetus to develop alternative environmentally-friendly energy sources. Therefore, the development of highly efficient technology for clean energy production is the foremost research priority worldwide. However, the large-scale commercialization of innovative technologies such as proton exchange membrane water electrolyzers (PEMWE) and fuel cell (PEMFC) is majorly thwarted by lack of high-performance electrocatalysts for catalyzing the energy-intensive electrochemical oxygen and hydrogen evolution reaction (OER-HER) of PEMWE and oxygen reduction and hydrogen oxidation reaction (ORR-HOR) of PEMFC. Therefore, identification, development, and engineering of novel reduced platinum group metal (PGM) containing as well as PGM-free electrocatalysts (ECs) for oxygen and hydrogen electrocatalysis as well as the development of photoanodes are of paramount importance in fostering commercialization of PEMWE, PEMFC as well as solar-energy driven photoelectrochemical (PEC) water-splitting devices. Accordingly, the present work focuses on the synthesis and fundamental study of OER, ORR, HER, HOR ECs, and photoanodes for PEC water splitting.
Accordingly, employing thermodynamics and kinetics based density functional theory (DFT), the as-synthesized reduced PGM based (Mn,Ir)O2:F thin films/nanorods and (Sn,Ir)O2:F nanotubes (NTs) and PGM-free (Mn, Nb)O2:F NTs and Cu1.5Mn1.5O4 including Cu1.5Mn1.5O4:F display remarkably higher electrochemical performance than benchmark IrO2 and many PGM/PGM-free ECs for OER in PEMWE. Furthermore, as-synthesized PGM-free Co and S containing Ni2P [(Ni0.95Co0.05)2P:S] system exhibits excellent HER performance comparable to benchmark Pt/C for PEMWE.
Similarly, for PEMFC, a PGM-free spinel Cu1.5Mn1.5O4, Cu1.5Mn1.5O4:F and ultra-low PGM based Pt doped titanium silicide [(Ti1-xPtx)5Si3] ECs are engineered for ORR and HOR, respectively. These studies provide fundamental insight into influence of ordered-disordered structures and rearrangement of oxidation state of active species and their combined synergistic effects on the electrochemical performance (ORR) for PEMFC. In the PEC water splitting area, in order to enhance the optoelectronic properties and PEC performance, as-developed (W0.98Mo0.02)O3-(Sn0.95Nb0.05)O2:N bilayer photoanode reveals an excellent performance with promising solar-to-hydrogen efficiency (STH) for PEC water splitting. This dissertation provides a detailed account of the fundamental study conducted into the materials identification, synthesis, development, and physicochemical- electrochemical characterizations ably supported by DFT studies.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
3 September 2021 |
| Date Type: |
Publication |
| Defense Date: |
1 March 2021 |
| Approval Date: |
3 September 2021 |
| Submission Date: |
19 April 2021 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
540 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Chemical and Petroleum Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Electrocatalysts, Hydrogen, Fuel cell, Proton exchange membrane water electrolyzer, Density functional theory, clean energy |
| Date Deposited: |
03 Sep 2022 05:00 |
| Last Modified: |
03 Sep 2023 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/40655 |
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