Masters Theses

Abstract

"Nickel nanoparticles were synthesized by gamma-radiation and femtosecond laser ablation. Aqueous precursors were prepared by uniformly dispersing nickel chloride in a 2:1 ratio of water and isopropanol. Stabilizers employed were Sodium Dodecyl Sulfate (SDS) and Poly Vinyl Pyrrolidone (PVP). Gamma-ray radiolysis of aqueous nickel precursors was investigated as a reducing agent for nickel cations to form atomic seeds for nucleation on multi-walled carbon nanotubes (MWCNTs). 30-60kGy was the dosage used in increments of 10kGy, at a rate of 10kGy/hr. Isopropanol was added to consume the excess of oxidizing species produced by irradiation and form stable secondary radicals. The influence of an added substrate was studied by adding multi-walled carbon nanotubes. Post-irradiation analysis by STEM, TEM and XPS yielded nickel nanoparticle sizes in the range of 9-15nm, with characteristic XPS peaks confirming the reduction of divalent nickel ions to nickel atoms. The presence of MWCNTs is proposed to adsorb a single nanoparticle at an active site and nucleation proceeds from an adsorbed nanoparticle to form larger clusters. The difference in particle sizes is evident from the average particle size distributions with increasing doses of radiation. Suspensions of nickel nanoparticles were also synthesized by femtosecond laser ablation. Pure nickel foil was subjected to laser pyrolysis in water, causing the divalent nickel cations to enter the plasma phase and cool down as nickel atoms in the liquid phase. These nickel particles were transferred to acetone, post-synthesis in deionized (DI) water. Suspensions were investigated for particle size, geometry and stability by STEM and TEM. Nickel nanoparticles of highest frequency were formed in the 3-10nm range. EDX and XPS were used to confirm chemical compositions and oxidation states of nickel atoms thus obtained"--Abstract, Page iv.

Advisor(s)

Castaño, Carlos H.

Committee Member(s)

Al-Dahhan, Muthanna H.
Neogi, P. (Partho), 1951-

Department(s)

Chemical and Biochemical Engineering

Degree Name

M.S. in Chemical Engineering

Sponsor(s)

Missouri University of Science and Technology. Department of Chemistry
Missouri University of Science and Technology. Department of Nuclear Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2012

Pagination

x, 57 pages

Note about bibliography

Includes bibliographical references (pages 28-30).

Rights

© 2012 Vivek M. Rao, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Gamma rays
Nanoparticles -- Research
Femtosecond lasers
Laser pulses, Ultrashort
Laser ablation

Thesis Number

T 10068

Print OCLC #

847524613

Electronic OCLC #

847524706

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