Graduation Year

2012

Document Type

Thesis

Degree

M.S.C.H.

Degree Granting Department

Chemical Engineering

Major Professor

John N. Kuhn

Keywords

Colloid Chemistry, Ethylene Hydrogenation, Heterogeneous Catalysis, Noble Metal, Size Dependence, Sulfur Tolerance

Abstract

A large concern of the fossil fuel and renewable energy industries is the sulfur poisoning of catalysts. In the case of noble metals, such as platinum, it is seen that there is a size trend associated with the level of activity in the presence of sulfur. Smaller nanoparticles could be more tolerant due to sulfur surface vacancies. On the other hand, larger particles could have less deactivation because the sulfur is more attracted to the smaller particles and the sulfur molecules bind stronger to these smaller particles.

The size effect of sulfur deactivation was investigated by testing four sizes of nanoparticles, ranging from 2 - 7 nm with and without sulfur by running an ethylene hydrogenation reaction. The synthesized particles were characterized by mass spectrometry, X - ray diffraction, and transmission electron microscopy. The 7 nm catalyst resulted in being the most sulfur tolerant due to the sulfur particles binding strongly to the smaller particles.

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