Colloidal design of active, selective, and stable catalysts for methane utilization

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Due to recent advances in locating and extracting natural gas resources, scientists in academia and industry are looking for new processes to take advantage of methane as a chemical precursor and fuel. However, there remain significant challenges in methane utilization; these are related to the strength of methane's carbon-hydrogen bonds, which makes this molecule difficult to activate and utilize. Without a catalyst, methane activation necessitates very high temperatures (~1000 oC), which lead to high energy costs, advanced infrastructure, toxic by-products, and poor product selectivity. Our work focuses on developing catalysts with well-defined structural properties to understand what makes materials active, selective, and stable for methane transformations. To understand which specific nanostructures are best for methane activation, size- and composition- controlled Pt/Pd nanocrystals were designed and studied to reveal the effect of catalyst structure on methane activation. Here, we discuss the effect of these unexplored parameters on methane activation rates, resistance to common catalytic poisons, and changes in oxidation state -- each of which has an important role in contributing to low-temperature activity. Perhaps the greatest challenge in methane activation is selective product formation. In this area, we studied how tuning catalyst support can help selectively produce valuable products (synthesis gas) rather than typical combustion products (carbon dioxide and water). Additionally, we started looking at even more unique nanostructures, involving both organic and inorganic components, for selective methane transformations. The high temperatures needed to activate methane require stable catalysts. By taking advantage of modular colloidal catalyst assembly, we demonstrated synthetic approaches to tune, and measure, the spatial properties of nanocrystal active sites. We found that in many conditions, the spatial properties of active sites determined catalyst stability. In Pd/Al2O3 materials we observed that closer nanocrystals are more stable, in a distant-dependent degradation process. However, in Pd/SiO2 materials we found the opposite - that stability properties are largely distant-independent. Overall, by developing colloidal approaches to catalyst synthesis, we created well-defined catalysts with precisely-controlled sizes, compositions, and spatial properties, which have helped us uncover important design rules for active, selective, and stable methane transformations


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


Author Goodman, Emmett Daniel
Degree supervisor Cargnello, Matteo
Thesis advisor Cargnello, Matteo
Thesis advisor Abild-Pedersen, Frank
Thesis advisor Bent, Stacey
Degree committee member Abild-Pedersen, Frank
Degree committee member Bent, Stacey
Associated with Stanford University, Department of Chemical Engineering


Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Emmett Daniel McGrenra Goodman
Note Submitted to the Department of Chemical Engineering
Thesis Thesis Ph.D. Stanford University 2020
Location electronic resource

Access conditions

© 2020 by Emmett Daniel Goodman
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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