Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures

Cobalt is a ferromagnetic material while cobalt-gold bimetallic particles are expected to have modulated magnetic properties. Besides, gold nanostructure is also a good plasmonic material. However, cobalt is susceptible to oxidation in aqueous environment. The oxidised layer can harm the magnetic...

Full description

Saved in:

Bibliographic Details
Main Author:	Khe, Cheng Seong
Format:	Thesis
Language:	English
Published:	2013
Subjects:	TN1-997 Mining engineering Metallurgy
Online Access:	http://eprints.usm.my/43530/1/KHE%20CHENG%20SEONG24.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-usm-ep.43530
record_format	uketd_dc
spelling	my-usm-ep.435302019-04-12T05:26:16Z Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures 2013-05 Khe, Cheng Seong TN1-997 Mining engineering. Metallurgy Cobalt is a ferromagnetic material while cobalt-gold bimetallic particles are expected to have modulated magnetic properties. Besides, gold nanostructure is also a good plasmonic material. However, cobalt is susceptible to oxidation in aqueous environment. The oxidised layer can harm the magnetic properties. Therefore, in order to avoid oxidation of cobalt, this work was devoted to the synthesis of cobalt and cobalt-gold bimetallic hierarchical particles using polyol method cum galvanic replacement reaction. A number of synthesis conditions were experimented in order to investigate their impacts on the morphologies of the cobalt particles produced. The parameters studied including reaction time, sodium hydroxide, concentration of cobalt salt, reaction temperature, reducing agent and surfactants. Various morphologies were successfully prepared such as hierarchical microspheres, hierarchical polyhedral shape, hierarchical raspberry like, truncated hexagonal bipyramid, flower-like, elongated and quasi cubic-like particles. All of these hierarchical cobalt particles exhibited their own unique magnetic properties. Sample prepared from 1mmol cobalt chloride, 2 mmol of sodium hydroxide, 5 mmol of hydrazine hydrate and 3.0% (w/v) of sodium dodecyl sulfate has a mixture of quasi cubic and elongated particles. It has the highest coercivity of about 290 Oe. Cobaltgold bimetallic hierarchical particles were prepared by galvanic replacement reaction where cobalt acted as sacrificial template. Bimetallic particles with hollow hierarchical structure and arbitrary shapes were produced under different synthesis conditions. 2013-05 Thesis http://eprints.usm.my/43530/ http://eprints.usm.my/43530/1/KHE%20CHENG%20SEONG24.pdf application/pdf en public phd doctoral Universiti Sains Malaysia Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	TN1-997 Mining engineering Metallurgy
spellingShingle	TN1-997 Mining engineering Metallurgy Khe, Cheng Seong Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
description	Cobalt is a ferromagnetic material while cobalt-gold bimetallic particles are expected to have modulated magnetic properties. Besides, gold nanostructure is also a good plasmonic material. However, cobalt is susceptible to oxidation in aqueous environment. The oxidised layer can harm the magnetic properties. Therefore, in order to avoid oxidation of cobalt, this work was devoted to the synthesis of cobalt and cobalt-gold bimetallic hierarchical particles using polyol method cum galvanic replacement reaction. A number of synthesis conditions were experimented in order to investigate their impacts on the morphologies of the cobalt particles produced. The parameters studied including reaction time, sodium hydroxide, concentration of cobalt salt, reaction temperature, reducing agent and surfactants. Various morphologies were successfully prepared such as hierarchical microspheres, hierarchical polyhedral shape, hierarchical raspberry like, truncated hexagonal bipyramid, flower-like, elongated and quasi cubic-like particles. All of these hierarchical cobalt particles exhibited their own unique magnetic properties. Sample prepared from 1mmol cobalt chloride, 2 mmol of sodium hydroxide, 5 mmol of hydrazine hydrate and 3.0% (w/v) of sodium dodecyl sulfate has a mixture of quasi cubic and elongated particles. It has the highest coercivity of about 290 Oe. Cobaltgold bimetallic hierarchical particles were prepared by galvanic replacement reaction where cobalt acted as sacrificial template. Bimetallic particles with hollow hierarchical structure and arbitrary shapes were produced under different synthesis conditions.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Khe, Cheng Seong
author_facet	Khe, Cheng Seong
author_sort	Khe, Cheng Seong
title	Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
title_short	Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
title_full	Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
title_fullStr	Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
title_full_unstemmed	Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures
title_sort	role and correlation of synthesis, size and morphology to the magnetic properties of cobalt and cobalt/gold bimetallic hierarchical nanostructures
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral
publishDate	2013
url	http://eprints.usm.my/43530/1/KHE%20CHENG%20SEONG24.pdf
_version_	1747821234441158656

Role And Correlation Of Synthesis, Size And Morphology To The Magnetic Properties Of Cobalt And Cobalt/Gold Bimetallic Hierarchical Nanostructures

Similar Items