Structure-activity relationships in CO2 electroreduction catalysis
Abstract/Contents
- Abstract
- Developing structure-activity relationships in CO2 electroreduction catalysts is critical to rationally synthesizing electrode materials with improved performance. While many studies have drawn correlations between the activity, selectivity, and stability of a CO2 electroreduction catalyst and catalyst particle size, shape, composition, roughness, comparatively less had been established about how bulk defects influence surface reactivity. We hypothesized that bulk defects could stabilize reactive surfaces that persist through electrolytic conditions and alter the reactivity of more ordered surfaces. In this dissertation, we detail our efforts to obtain the first direct evidence that CO2 electroreduction in enhanced at the surface terminations of grain boundaries (GBs) and dislocations. We used scanning electrochemical cell microscopy (SECCM) to show that the surface terminations of GBs engender regions of enhanced CO2 electroreduction activity that can be several µms wide. The magnitude of enhancements appeared to depend on local GB structure and ranged between 10%-300% relative to the adjacent grains. In contrast, the competing H2 evolution reaction was relatively insensitive to the presence of these defects. Mapping the lattice deformation of the regions surrounding these bulk defects using electron diffraction suggested that the local density of dislocation surface terminations, instead of local lattice strain, were correlated to the observed enhancements. Beyond electroanalytical SECCM studies, we demonstrated the utility of engineering bulk defects in CO2 electroreduction catalysts by showing that mechanical treatment enhances CO2 electroreduction by introducing new GBs and dislocations, while the H2 evolution reaction remains relatively unaffected. In addition, we report the development and validation of a scanning electron microscope (SEM)-based technique to rapidly and accurately characterize the grain orientation and defect structure of polycrystalline nanoparticles, relieving a bottleneck imposed by the inaccessibility of existing grain mapping techniques. These studies establish a new structure space for electrocatalyst design and motivate the exploration of GB and dislocation engineering to develop improved catalysts for electrochemical transformations.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Mariano, Ruperto G |
|---|---|
| Degree supervisor | Kanan, Matthew William, 1978- |
| Thesis advisor | Kanan, Matthew William, 1978- |
| Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Thesis advisor | Dai, Hongjie, 1966- |
| Degree committee member | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Degree committee member | Dai, Hongjie, 1966- |
| Associated with | Stanford University, Department of Chemistry. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Ruperto G Mariano. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis Ph.D. Stanford University 2020. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Ruperto G Mariano
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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