U.S. Department of EnergyOffice of Scientific and Technical Information
Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications
Abstract
I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu2+ adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlledmore »
- Authors:
-
- Iowa State Univ., Ames, IA (United States)
- Publication Date:
- Research Org.:
- Ames Lab., Ames, IA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 837271
- Report Number(s):
- IS-T 2397
TRN: US200506%%92
- DOE Contract Number:
- W-7405-Eng-82
- Resource Type:
- Thesis/Dissertation
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); PBD: 19 Dec 2004
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; ADSORPTION; CAPACITY; CATALYSIS; CATALYSTS; ELECTRON MICROSCOPY; FUNCTIONALS; MORPHOLOGY; REACTION KINETICS; SHAPE; SILICA; SORPTION; SUBSTRATES; ZEOLITES
Citation Formats
Huh, Seong. Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications. United States: N. p., 2004.
Web. doi:10.2172/837271.
Huh, Seong. Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications. United States. https://doi.org/10.2172/837271
Huh, Seong. 2004.
"Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications". United States. https://doi.org/10.2172/837271. https://www.osti.gov/servlets/purl/837271.
@article{osti_837271,
title = {Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications},
author = {Huh, Seong},
abstractNote = {I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu2+ adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is capable of activating two different substrates in aldol reaction, Henry reaction and cyanosilylation. One catalytic group activates the nucleophile, another organic group simultaneously activates the electrophile to enhance the total reaction rate. I systematically vaned the amount of two organic groups and performed the three model reactions to compare rate enhancements.},
doi = {10.2172/837271},
url = {https://www.osti.gov/biblio/837271},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Dec 19 00:00:00 EST 2004},
month = {Sun Dec 19 00:00:00 EST 2004}
}