Theoretical study on hydrogen interaction with calcium decorated silicon carbide nanotube

• Main Author: Gueriba, Jessiel S.
• Format: text
• Language: English
• Published: Animo Repository 2015
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4837
• Institution: De La Salle University

Hydrogen storage poses limitations in maximizing the use of hydrogen as an energy source for industrial applications. The search and realization of lightweight materials which can store significant amount of hydrogen in its condensed form, at ambient conditions, is still a continuing challenge for researchers today. A first principles study on the viability of calcium decorated silicon carbide nanotube (SiCNT) as a hydrogen storage material was conducted. Silicon carbide strongly enabled Ca decoration, evident on calciums large binding energy of -2.83 eV on the hollow site of the nanotube. Calciums low cohesive energy and strong binding with SiCNT may prevent the metal decoration to form clusters with other adsorbates. Bader charge analysis also revealed that there is a charge transfer of 1.45e from Ca to SiCNT resulting to calcium's cationic state that may induce charge polarization to a nearby molecule such as hydrogen. Hydrogen molecule was then allowed to interact with the metal adsorbate where it indeed exhibits charge polarization, induced by the electric field emanating from calciums cationic state. This resulted to a significant binding energy of -0.22 eV. Multiple hydrogen was placed on the remaining adsorption sites near the calcium adatom with and without van der Waals correction. Results show that one Ca adatom can hold up to 6 hydrogen molecules without van der Waals correction while it can hold up to 7 hydrogen molecules with van der Waals correction with a much enhanced binding energy. Results reveal that Ca on SiCNT can be a promising candidate for a hydrogen storage material.