Ambient pressure XPS studies on electrochemical reactions
Abstract/Contents
- Abstract
- Capable of converting electricity into chemicals and chemicals into energy, heterogeneous electrocatalysis is a promising field in the development of clean, renewable energy. At the present time, further development in catalyst design and optimization is necessary to achieve the efficiencies necessary for electrocatalysis to be cost effective. In order to achieve rational catalytic design, it is paramount to understand the fundamental principles governing each electrocatalytic process, and that requires the utilization of spectroscopic techniques capable of probing the system in operando, i.e. as the chemical reaction is taking place. Among the many in operando techniques, Ambient Pressure X-ray Photoelectron Spectroscopy stands out for the interrogation of electrocatalytic processes due to its ability to probe a catalyst in a surface- and chemically-sensitive manner. This thesis shows the design of an APXPS-compatible electrochemical cell and its use to investigate three key electrochemical processes pertinent to the field of renewable energy. First, we investigated the oxygen reduction reaction (ORR), the rate-limiting step for the electrochemical combination of hydrogen and oxygen in a fuel cell device, on both pure platinum and platinum alloy catalysts. Second, we researched the electrolysis of water through the oxygen evolution reaction (OER) on an iridium oxide catalyst. Third, we investigated the electrochemical production of hydrogen from protons through the hydrogen evolution reaction (HER) on amorphous molybdenum nanoparticles. We conclude that APXPS electrochemistry is a powerful tool for understanding electrocatalytic processes, allowing for the elucidation of reaction mechanisms through intermediates that can only be observed in operando, such as the identification of non-hydrated hydroxide on platinum during ORR or the identification of the oxidation state of iridium oxide during OER. Furthermore, APXPS electrochemistry allows us to follow the activation processes undergone by catalysts under realistic reaction conditions, such as the dealloying process of Pt-Y nanoparticles or the transformation of MoSx into a predominantly MoS2 phase. This powerful technique can be extended to even more catalytic systems, and we believe that in the near future it will become a standard characterization tool for heterogeneous catalysis.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2014 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Sanchez Casalongue, Hernan |
|---|---|
| Associated with | Stanford University, Department of Chemistry. |
| Primary advisor | Nilsson, Anders, 1956- |
| Thesis advisor | Nilsson, Anders, 1956- |
| Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Thesis advisor | Jaramillo, Thomas Francisco |
| Advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Advisor | Jaramillo, Thomas Francisco |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Hernan Sanchez Casalongue. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Hernan Guido Sanchez Casalongue
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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