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ZnO nanoparticles (NPs) have been synthesized on porous silica microparticles, namely sand microparticles using the sol-gel technique. The ZnO NPs grown on the multifaceted surface of porous silica microparticles were applied as photocatalyst for the degradation of methylene blue (MB) in aqueous solution. The enhanced rate constant observed was due to two reasons. Firstly, the multifaceted surface of the sand substrate provided fixed space for growth space which prevented agglomeration of the ZnO NPs photocatalyst, thus maintaining a large surface area. Secondly, the presence of nanopores on the sand surface provided adsorption sites for MB molecules to be in the vicinity of the photocatalyst. The photocatalytic activity was significantly enhanced where photodegradation efficiency of supported ZnO NPs reached 71.7% compared to 48.2% for unsupported ZnO NPs under UV light irradiation within 150 min. The values of k increased from 4.3 9 10 -3 min -1 to 8.6 9 10 -3 min -1 for unsupported and supported ZnO NPs, respectively.

Abstract. In this work, we have synthesized carbon nanotubes (CNT) using different biohydrocarbon precursors namely palm, olive, coconut, corn and sesame oils. Prior to the synthesis process, thermogravimetric analysis (TGA) characterization was performed on the carbon precursors to facilitate the optimization procedures of CNT and reach maximum yield and higher quality CNT.The CNT arrays were deposited on a silicon substrate by thermal catalytic decomposition of the precursor using 5.33 wt% ferrocene. The synthesis was carried out at 750 °C for 60 min under argon ambient. The samples were characterized using field emission scanning electron microscopy, microRaman spectroscopy and TGA analysis. The difference in oil density resulted in different quality and Nano HybridsOnline -08-22 ISSN: 2234-9871, Vol. 2, pp 43-63 doi:10.4028/www.scientific.net/NH.2.43 © 2012 This is an open access article under the CC-BY 4.0 license (https://creativecommons.org/licenses/by/4.0/) tube diameter of CNT produced. Among all, the CNT synthesized from coconut oil can be considered as the best bio-hydrocarbon precursor for higher quality (I D /I G ~0.62) and good purity (81.95 %) CNT.

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In this study we report the effect of various synthesis temperatures of 600 - 1000°C for the synthesis of carbon nanotubes (CNT). Bio-hydrocarbon precursor namely palm oil was utilized as a starting material by thermal vapor deposition method. Ferrocene at 5.33 wt% was directly mixed with palm oil precursor for 30 mins synthesis time. The prepared CNT was collected from the furnace wall and then characterized by field emission scanning electron microscopy, scanning transmission electron microscopy, fourier transform infrared spectroscopy and thermogravimetric analysis. The density, diameter and the purities of the CNT were found to be highly dependent on the temperature changes. The synthesis temperature of 800°C was considered to be the optimum temperature for higher quality and quantity of CNT production.