Date of Publication

4-2019

Document Type

Master's Thesis

Degree Name

Master of Science in Physics

Subject Categories

Biological and Chemical Physics

College

College of Science

Department/Unit

Physics

Thesis Adviser

Nelson B. Arboleda, Jr.

Defense Panel Chair

Michelle T. Natividad

Defense Panel Member

Christopher T. Que
Raymund B. Bolalin

Abstract/Summary

The most commonly used catalysts in FT synthesis are transition metals, which involves iron, cobalt, and ruthenium. On the other hand, osmium (Os) belongs to group 8 elements together with iron and ruthenium a hexagonal close-packed crystal structure like cobalt and ruthenium, with greater lattice parameters. This study focused on the initiation stage of the FT synthesis where carbon monoxide (CO) is adsorbed on the metal surface. This study determined adsorption energy of CO/Os system for each adsorption site on both surfaces of osmium, the dissociation energy of the oxygen, their corresponding density of states and charge difference profiles with the use of Density Functional theory implemented by VASP. The results showed that the density of states of osmium exhibits symmetry between the spin up and spin down states. Presence of states in the Fermi level was also observed, indicating that osmium is a non-magnetic metal. The calculated adsorption energy on the most preferred site for each surface was -2.04 eV and -2.07 eV respectively, while the calculated dissociation energy was -8.44 eV and -9.31 eV for Os (0001) and Os 1121 respectively. Osmium (0001) was a better surface for FT synthesis compared to Os 1121

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG007353

Keywords

Carbon monoxide—Absorption and adsorption; Fischer-Tropsch process; Osmium

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Embargo Period

7-27-2022

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