Sol Gel Process Of Cobalt Nanopracticles Preparation As Effective Catalyst For CNT Growth Performance

• Main Author: Zulkapli, Nor Najihah
• Format: Thesis
• Language: English; English
• Published: 2016
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/18201/1/Sol%20Gel%20Process%20Of%20Cobalt%20Nanopracticles%20Preparation%20As%20Effective%20Catalyst%20For%20CNT%20Growth%20Performance%2024%20Pages.pdf; http://eprints.utem.edu.my/id/eprint/18201/2/Sol%20Gel%20Process%20Of%20Cobalt%20Nanoparticles%20Preparation%20As%20Effective%20Catalyst%20For%20CNT%20Growth%20Performance.pdf; http://eprints.utem.edu.my/id/eprint/18201/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=100101

Carbon nanotube (CNT) is a well known structure that has extraordinary properties and widely used in many application. The presence of metal catalyst is needed for CNT growth by CVD technique. The properties of as-grown CNT is depends on the properties of metal catalyst. The aim of this project was to produce cobalt (Co) catalyst by spin coating process for carbon nanotube (CNT) growth. It was targeting to study the catalyst thin film formation by using solution process, analyze the catalyst nanoparticles transformation from the deposited thin film and confirm the structural properties of as-grown CNT by Raman spectroscopy. This project was divided into two major parts. The first part was catalyst preparation and the second part was CNT growth. The Co catalyst was prepared by spin coating and heat treatment process. The spin speed of spin coating was varied from 6500 rpm to 8000 rpm with 500 rpm interval and spinning duration of 60 s. The post-heat treatment temperature was varied from 450 ⁰C to 600 ⁰C with interval of 50 ⁰C and heating duration of 10 minutes. The Co catalyst nanoparticles formed after heat treatment process then being used for CNT growth by alcohol catalytic CVD (ACCVD) technique. The CVD processing temperature was varied in range of 650-750 ⁰C with 25 ⁰C interval. The CVD processing time was fixed for 15 minutes. The Co catalyst and its nanoparticles were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) while the structural properties of the as-grown CNT was studied by Raman spectroscopy. The thickness of Co catalyst thin film was decreasing by the increasing of spin speed. Based on four varied value of spin speed; 6500, 7000, 7500 and 8000 rpm, the optimum spin speed with smallest thickness of Co catalyst thin film, 12.1 nm, was at 8000 rpm. Besides, the average size of Co nanoparticle was increased by the increasing of post-heat treatment temperature. The optimum temperature was found at 450 ⁰C with 10.64 nm average size of Co nanoparticles. The Co catalyst thin film was confirmed by XRD and XPS analysis to have CoO compound structure while the Co catalyst nanoparticles was in Co3O4 structure. Then, 700 ⁰C was found to be the optimum CVD processing temperature for the CNT grown on spin coated Co catalyst nanoparticles with the highest IG/ID ratio of 6.398. Additionally, the presence of SWCNT structure was confirmed by the presence of RBM peak in range of 100-400 cm-1 Raman shift measured by Raman spectroscopy. The measured SWCNT tube diameters were less than 1.5 nm. Hence, it can be concluded that the thickness of Co catalyst thin film can be controlled by controlling the spin speed of spin coating. Optimum post-heat and CVD processing temperature is crucial for Co catalyst nanoparticles formation and obtaining good quality of CNT. The as-grown CNT in this project has high potential in electronic device application due to the smaller SWCNT tube diameter and good quality.