Morphological and Structural Studies of Titanate and Titania Nanostructured Materials Obtained after Heat Treatments of Hydrothermally Produced Layered Titanate

Mohd Hasmizam Razali,Abdul Rahman Mohamed,Srimala Sreekantan,Ahmad-Fauzi Mohd Noor

doi:10.1155/2012/962073

Mohd Hasmizam Razali, Abdul Rahman Mohamed + Show 2 more

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https://doi.org/10.1155/2012/962073

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Abstract

Different types of titanate and titania nanostructured materials have been successfully synthesised and characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and raman spectroscopy. Elemental analysis was determined by energy dispersive X-ray spectroscopy (EDX) analyzer while thermogravimetric-differential scanning calorimetry (TG-DSC) was used to determine thermal stability. In this study, we found that nanotubes were formed during the washing treatment stage with HCl and distilled water. When the pH of the washing solution was 12, sodium titanate nanotubes were obtained, while when the pH of the washing solution was 7, hydrogen titanate nanotubes were obtained. Sodium titanate nanotubes were thermally stable up to 500°C; however, at 700°C, the nanotubes structure transform to solid nanorods. Meanwhile, hydrogen titanate nanotubes decomposed to produce titania nanotubes after heat treatment at 300°C for 2 hours. At 500°C, the tubular structure broke to small segments due to destruction of the nanotube. Further heat treatment at 700°C, led to the destruction and collapse of the nanotubes structure produce titania nanoparticles.

Highlights

After years of evolutionary research on titanate and titania nanostructured material production, many technologies based on “bottom up” processes such as the sol-gel method [1,2,3], chemical vapour deposition [4], template method [5], anodic anodization method [6], and hydrothermal method [7] have been developed
Elemental analysis was determined by energy dispersive X-ray spectroscopy (EDX) analyzer while thermogravimetric-differential scanning calorimetry (TG-DSC) was used to determine thermal stability
The layered-like structure of Na2Ti3O7 was shown in the field emission scanning electron microscopy (FESEM) micrograph (Figure 1) containing Na, Ti, and O as indicated by EDX (Figure S5)

Summary

Introduction

After years of evolutionary research on titanate and titania nanostructured material production, many technologies based on “bottom up” processes such as the sol-gel method [1,2,3], chemical vapour deposition [4], template method [5], anodic anodization method [6], and hydrothermal method [7] have been developed. The hydrothermal method, based on wet chemistry method, is a versatile heterogeneous chemical reaction in the presence of a solvent, aqueous or nonaqueous, conducted in steel pressure vessels called autoclaves with or without Teflon liners under controlled temperature and pressure [8]. Even though the hydrothermal method has caught the interest of researchers to synthesize nanostructured titanate It is possible to grow nanostructured metal oxides by dissolution and crystallization, thereby creating a distinctive difference in their characteristics at the nanoscale level [8].

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