Mohd Shahril Amin Bistamam

Aligned carbon nanotube from catalytic chemical vapor deposition technique for energy storage device: a review

Carbon nanomaterial especially carbon nanotube (CNT) possesses remarkably significant achievements towards the development of sustainable energy storage applications. This article reviews aligned CNTs grown from chemical vapor deposition (CVD) technique as electrode material in batteries and electrochemical capacitors. As compared to the entangled CNTs, aligned or well-organized CNTs have advantages in specific surface area and ion accessibility in which more electrolyte ions can access to CNT surfaces for better charge storage performance. CVD known as the most popular technique to produce CNTs enables the use of various substrates and CNT can grow in a variety of forms, such as powder, films, aligned or entangled. Also, CVD is a simple and economic technique, and has good controllability of direction and CNT dimension. High purity of as-grown CNTs is also another beauty of the CVD technique. The current trend and performance of devices utilizing CNTs as electrode material is also extensively discussed.

Extraction of cellulose nanofiber from waste papers and application to reinforcement in biodegradable composites

Cellulose nanofibers have shown great potential to improve mechanical and physical properties in polymer-based composites. We aimed to extract the cellulose nanofibers from waste newspaper as a high-yield cellulosic source. First the newspaper was treated chemically and physically in order to extract individualized cellulose nanofibers from their cellulosic matrix. Then acid hydrolysis and mechanical treatments resulted in the cellulose nanofibers of diameter between 10 and 40 nm. The reinforcing effect of obtained cellulose nanofibers from waste newspaper was investigated by composing with a starch-based dispersion-type biodegradable resin CP-300, Miyoshi Oil & Fat Co. Ltd, Japan. Commercially available cellulose nanofiber-reinforced composites were used as comparison to newspaper cellulose nanofiber-reinforced composites. The tensile test results show significant enhancement in mechanical properties of reinforced composites for both composites. However, commercially available cellulose nanofiber-reinforced composites showed greater enhancement than newspaper cellulose nanofiber-reinforced composites.

Control of Cobalt Catalyst Thin Film Thickness by Varying Spin Speed in Spin Coating towards Carbon Nanotube Growth

Cobalt (Co) catalyst thin film is an active metal catalyst that can be very helpful to grow carbon nanotubes (CNTs). The catalyst thin films were prepared on silicon wafers by spin coating the solution of cobalt acetate tetrahydrate and ethanol. The effects of different spin speed parameter during the spin coating process were investigated. The findings showed that the optimum thickness of the Co catalyst thin films, i.e., 12.1 nm, was obtained at the highest spin speed of 8000 rpm. The uniformity of the thin films was also found to increase with increasing spin speed. The study also demonstrated that single-walled carbon nanotubes could be grown from Co catalyst particles after the catalytic chemical vapor deposition of ethanol. The particle and thickness analysis, as performed by means of FESEM while the existence of CNTs, was performed by Raman spectroscopy.

An overview of selected catalytic chemical vapor deposition parameter for aligned carbon nanotube growth

Aligned carbon nanotube (A-CNT) has been extensively studied due to their high potential in many applications. Despite the fact that catalyst preparation is the key role to grow A-CNTs, the parameter of catalytic chemical vapor deposition (C-CVD) also influences A-CNT growth and its morphologies. This review focused to critically synthesize the published data in scientific report on A-CNT for better understanding the C-CVD parameter governing vertically A-CNT growth. The review will mainly discuss the influence of C-CVD processing temperature, C-CVD processing time, and carbon feedstock in A-CNT growth and its effects on A-CNT morphologies. Challenges and future perspectives in the synthesis of aligned carbon nanotubes have also been discussed.

Electrochemical Performance of Multi Walled Carbon Nanotube and Graphene Composite Films Using Electrophoretic Deposition Technique

This study aims to investigate multi-walled carbon nanotube and graphene composite thin films fabricated using cathodic electrophoretic deposition in aqueous solution. The deposition mechanism and films microstructure were investigated using the cyclic voltammetry (CV) and field emission scanning electron microscope. The depositions yield varied by the deposition time and deposition voltage. The composite films were studied for its application in the electrochemical capacitor. The electrochemical performance showed the capacitive behavior of the films in 6 M potassium hydroxide electrolyte. CV scans were verified from 0 to 1 V at different scan rates. The specific capacitance of 29 Fg-1 was achieved at the scan rate of 1 mVs-1.

Surface Interaction Between Carbon Patches and Catalyst Nanoparticle as the Key Factor in Aligned Carbon Nanotube Growth Using Alcohol Catalytic CVD

Aligned carbon nanotubes (ACNTs) have very unique properties that made them applicable as electrode material for energy storage devices. ACNTs were grown directly on substrates by catalytic chemical vapor deposition (CVD). Cobalt, thermally-oxidized aluminum and ethanol were used as catalyst, catalyst-support and carbon feedstock, respectively. Optimum catalytic and reaction conditions were investigated by varying the CVD processing temperature and time. CVD processing temperature of 725∘C and processing time at 10min showed the optimum CNT alignment with thickness of above 2μm. Other than the effect of catalyst particle diameter, formation of amorphous carbon at the top of CNTs observed by SEM is suggested as another factor that influences the growth mechanism of ACNTs. The CVD processing parameter and the interaction between small carbon patches are supposed to be built after dehydrogenation of the first carbonaceous molecules and the catalyst nanoparticle surface considered as the hidden factors behind the growth results.

Cyclic Voltammetry Analysis of Carbon Based Electrochemical Capacitor in Aqueous Electrolytes

In this study, a mixture of activated carbon (AC) and graphene (G) was coated onto the stainless steel (SS) mesh to produce an electrode for the electrochemical capacitor (EC). Different materials, such as carbon nanotube (CNT) mixed with G, were also used in this experiment to compare the electrochemical properties of both electrodes. The electrochemical properties of the electrode were determined by using cyclic voltammetry (CV). The CV curves of the AC/G electrodes showed good capacitive behaviour, and the highest capacitance values obtained for AC/G and CNT/G electrodes in 1M H2SO4 at 1 mVs-1 were 13 Fg-1 and 4.34 Fg-1, respectively. Meanwhile, the highest capacitance values obtained in 6M KOH at 1 mVs-1 were 14 Fg-1 and 12.07 Fg-1 for AC/G and CNT/G electrodes, respectively.

Fabrication of Activated Carbon Filled Epoxidized Natural Rubber Composite Using Solvent Casting Method

Despite the rapid increase in the utilization of reinforced nanomaterials composites, micromaterials may also have the potential to be utilized as filler in polymer composites. In this study, the activated carbon (AC) filled epoxidized natural rubber (ENR) composite was fabricated using the solvent casting method. AC was used as the filler at different filler addition in range from 0 to 7 parts per hundred rubbers (phr). The intention was to investigate the effect of AC filled ENR on mechanical properties and interaction between AC and ENR matrix. Overall, the result shows high improvement in mechanical properties. At 7 phr, the tensile strength was 7.0 MPa compared to 2.6 MPa for 0 phr, which indicates the increase by almost 2 times. The elongation also increases for all phr, which indicates the good filler effect.