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In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm2 (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

The objective of this research work is to determine the effect of ionic liquids on the vapor liquid equilibrium behaviour of methanol and ethyl acetate binary system at atmospheric pressure. The ionic liquids used in the experiments are: 1-ethyl-3-methylimidazolium Chloride [EMIM][Cl], 1-ethyl-1-methylpyrrolidinium Bromide [EMPyrr][Br]. Vapour-liquid equilibrium (VLE) experiments were conducted with Othmer still experimental setup and the VLE data sets were tested for thermodynamic consistency. The average deviations of experimental results were within the experimental toleration limits and satisfied the Gibbs-Duhem equation. The results showed that the addition of ionic liquids (ILs) caused salting-out effect of methanol from the system. For the same concentrations of the ionic liquids, [EMIM][Cl] is observed to be more effective than the [EMPyrr][Br] in breaking the azeotropes and in increasing the salting effect. For the 15% concentration of [EMPyrr][Br] the azeotrope was completely disappeared.

In this study, titanium dioxide nanotubes (TNT) were synthesis according to different concentration of sodium hydroxide (NaOH). The main purpose of this study was to investigate the effect of the high concentration NaOH towards formation of TiO 2 nanotubes structure. TNT was synthesized via hydrothermal method that was performed in a Teflon line stainless steel autoclave by using different concentration of NaOH (6 M to 12 M). The hydrothermal time and temperature is placed constantly for 24 hours and 110 o C respectively. The characterization of TNT was performed by Field Emission Transmission Electron Microscopy (FESEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray (EDX) analysis for better understanding of its nanotubes structure and the chemical bonding present. Based on characterization analysis, the formation of nanotubes was in systematic arrangement and makes it easier for loading of noble catalyst. Furthermore, the replacement of sodium content by hydrogen ion, H + also seem to be increasing after the acid washing treatment. The investigation result proven that the best concentration of NaOH for TiO 2 nanotubes formation was 10 M (TNT-10). Keywords: TiO 2 nanotubes, hydrothermal reaction, concentration of sodium hydroxide AbstrakMelalui kajian ini, nanotiub titanium dioksida disintesiskan mengikut kepekatan sodium hidrosida (NaOH) yang berbeza. Tujuan utama kajian ini adalah untuk mengkaji kesan kepekatan NaOH yang tinggi terhadap pembentukan struktur nanotiub. Nanotiub titanium dioksida (TNT) dihasilkan dengan menggunakan kaedah hidrotermal menggunakan turus teflon autoklaf keluli anti karat dengan mempelbagaikan kepekatan NaOH (6 M hingga 12 M). Tempoh dan suhu proses hidrotermal masing-masing dibiarkan sekata selama 24 jam dan 110 o C. Pencirian TNT dijalankan dengan menggunakan Mikroskopi Elektron Pengimbasan Pancaran Medan (FESEM), Pembelauan Sinar X (XRD), Spektroskopi Inframerah Transformasi Fourier (FTIR) dan Tenaga Serakan Sinar X (EDX) bagi memahami dengan lebih mendalam mengenai struktur nano dan juga ikatan kimia yang wujud. Berdasarkan analisis yang dijalankan, didapati nanotiub berada dalam keadaan yang sistematik dan memudahkan penempatan pemangkin adi. Tambahan pula, penggantian kandungan sodium oleh H + juga meningkat selepas proses pembasuhan menggunakan asid. Keputusan ujikaji menunjukkan kepekatan 10 M (TNT-10) adalah yang terbaik bagi menghasilkan nanotiub TiO 2 .Kata kunci: nanotiub TiO 2 , tindak balas hidrotermal, kepekatan sodium hidroksida ISSN -2506 Masturah & Siti Kartom: INFLUENCE OF HIGHLY CONCENTRATED SODIUM HYDROXIDE (NaOH) TOWARDS FORMATION OF HIGHLY ORDERED TIO 2 NANOTUBES (TNT) STRUCTURE 1406 IntroductionSince the discovery of carbon nanotubes (CNT) in 1990s, researchers are eager to find and develop more nanotubular structures with different types of materials that can be used for variable purpose. Due to over corrosive of carbon based materials, it seems to be less interesting for catalytic application and...

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