Carbon Coating for Improved Hydrothermal Stability of Silica Supports

A large number of industrial chemicals produced today come from petroleum-based feedstocks. With these feedstocks dwindling, it is necessary to develop alternative ways to produce these chemicals from biorenewable feedstocks. The move from the current petroleum-based chemical industry to a biorenewable chemical industry will build on a current platform chemical approach, where a small number of key chemical intermediates produced from biorenewable sources will serve as the platform to produce a broad range of chemical products. Since carbon is necessary to produce these chemicals, biomass, with its short formation time, must become the feedstock for the chemical industry. Since the new feedstock is in aqueous phase the catalyst supports used currently in the petroleum-based chemical industry, such as silica and alumina, will not work because they are not hydrothermally stable. Silica and alumina are used as catalyst supports because they are mechanically stable, have large surface areas, and synthesis methods are well established but they tend to react with water and lose their integrity during aqueous phase reactions at elevated temperatures. Mesoporous carbons are an attractive alternative to mesoporous oxides because they are thermally and chemically stable except in the presence of oxygen. The problem with these mesoporous carbons is they lack mechanical strength and their pore structure cannot be as easily tailored as that of the oxide supports. The central objective of this work was to integrate the benefits of both the mesoporous oxides (mechanical stability) and the mesoporous carbons (thermal and chemical stability) to produce hydrothermally stable catalyst supports. The approach used to combine the benefits of these supports was to deposit a thin layer of carbon within the pores of a mesoporous silica. By doing this, the mechanical stability of the mesoporous silica was retained and the support became thermally and chemically stable due to the thin layer of carbon on the silica support. The characterization techniques used to analyze the carbon-coated silica supports were FTIR, DRIFT, TGA, TEM, STEM, EFTEM, HRTEM, nitrogen adsorption surface area analysis, and hydrothermal treatments. This study successfully showed carbon from different precursors could be bound to the surface of Stober spheres, a model silica support, and to the surface and within the pores of SBA-15, a mesoporous silica.

Name thesis:degree_name

Nanoscience and Microsystems

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nanoscience and Microsystems

Year

2011

Author dc:creator

• Staker, Amanda Lynn

Contributors dc:contributor

• Datye, Abhaya
• Evans, Deborah
• Guo, Hua

• Carbon
• Supported Catalyst
• Hydrothermal Stability

Language dc:language

English

Identifier

https://digitalrepository.unm.edu/nsms_etds/28

OAI identifier oai:identifier

oai:digitalrepository.unm.edu:nsms_etds-1027