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ORCID
N/A
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Chemistry
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2015
Month Degree Awarded
February
Abstract
Density functional theory calculations were performed to study the dissociative chemisorption of methane over Pt(111) with the idea of finding the minimum energy path for the reaction and its dependence on surface coverage. Two approaches were used to evaluate this problem; first, we used different sizes of supercells (2x2, 3x3, 4x4) in order to decrease surface coverage in the absence of pre-adsorbed H and CH3 fragments to calculate the energy barriers of dissociation. The second approach uses a 4x4 unit cell and surface coverage is simulated by adding pre-absorbed H and CH3 fragments. Results for both approaches show that in general the height of the dissociation barriers increases as the surface coverage increases, although, the first approach yields slightly lower barriers due to the fact that all repeatable images of the incident molecule are approaching the surface simultaneously. Using the reaction path formulation we were able to compute the potential energy surface for CH4 dissociation. Our results suggest that excitation of the symmetric stretch and bend modes will likely increase the probability for reaction.
DOI
https://doi.org/10.7275/6465160
First Advisor
Bret Jackson
Second Advisor
Ricardo Metz
Recommended Citation
Colon-Diaz, Inara, "Catalytic Methane Dissociative Chemisorption over Pt(111): Surface Coverage Effects and Reaction Path Description" (2015). Masters Theses. 143.
https://doi.org/10.7275/6465160
https://scholarworks.umass.edu/masters_theses_2/143