Date of Award
Spring 5-1-2017
Track
Chemistry
Degree Type
Thesis
Degree Name
Master of Science in Chemical Sciences (MSCB)
Department
Chemistry
Committee Chair/First Advisor
Dr. Abbott Lyon
Committee Member
Dr. Mitchell
Committee Member
Dr. Van Dyke
Abstract
The study of dissociating methanol on vanadium surfaces was investigated in order to provide insight into reaction pathways for methane dissociation and partial oxidation into other feedstock chemicals. The construction of a custom-designed ultrahigh vacuum chamber was done to permit surface analysis to a greater extent than was previously available in the lab. Prior to experimentation, the clean vanadium surface was characterized through use of X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. This surface characterization revealed significant oxidation of the vanadium surface from atmospheric oxygen, water and carbon dioxide. The direct dissociation and partial oxidation of methane on a vanadium surface was studied experimentally with preliminary experimentation being conducted involving the direct dissociation of methanol on vanadium. This interaction between methanol and the vanadium surface was analyzed through a combination of reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD). At surface temperatures of 100 K, it was found that methanol adsorbs onto the vanadium surface dissociatively. While RAIRS experiments suggest that methanol and products desorb from the surface at 185 K, TPD suggests that some species remain until at least 225 K. At dosages of 10 L and greater, methanol adsorption induces oxidation of the vanadium surface as illustrated by the formation of features corresponding to V-O-V vibrations in the RAIRS.