Tailoring Mesoporous Titania Features by Ultrasound-Assisted Sol-Gel Technique: Effect of Surfactant/Titania Precursor Weight Ratio.

Elvira Mahu,Valeria Harabagiu,Cristina Giorgiana Coromelci,Doina Lutic,Maria Ignat,Iuliean Vasile Asaftei,Liviu Sacarescu

doi:10.3390/nano11051263

Elvira Mahu, Valeria Harabagiu + Show 5 more

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https://doi.org/10.3390/nano11051263

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Abstract

A mesoporous titania structure has been prepared using the ultrasound-assisted sol-gel technique in order to find out a way to tailor its structure. The TiO2 obtained was compared to the same version of titania but synthesized by a conventional sol-gel method with the objective of understanding the effect of ultrasound in the synthesis process. All synthesis experiments were focused on the preparation of a titania photocatalyst. Thus, the anatase photocatalytic active phase of titania was proven by X-ray diffraction. Additionally, the ultrasonation treatment proved to increase the crystallinity of titania samples, being one of the requirements to having good photocatalytic activity for titania. The influence of surfactant/titania precursor weight ratio on the structural (XRD), textural (N2-sorption measurements), morphological (TEM), surface chemistry (FTIR) and optical properties (UVDR) was investigated. It was observed that the crystallite size, specific surface area, band gap energy and even photocatalytic activity was affected by the synergism occurring between cavitation effect and the surfactant/titania precursor weight ratio. The study yielded interesting great results that could be considered for further application of ultrasound to tailor mesoporous titania features via sol-gel soft template synthesis, against conventional sol-gel process.

Highlights

In the past decade, an important semiconductor with huge potential for applications in various areas of nanotechnology has caught researcher’s attention
According to X-ray diffraction (XRD) patterns, all three samples exhibited a dominant anatase-phase of TiO2, proven by the diffraction peaks displayed in Figure 1, which are associated with the planes indexed as [101], [004], [200], [105], [211], [204], and [116], each corresponding to 2θ = 25.4, 38, 48, 54, 54.8, 62.5, and 68.8, respectively [23]
Mesoporous titania was prepared by hydrolysis-condensation of an organic titanium salt, titanium (IV) isopropoxide (TTIP), by simple conventional stirring

Summary

Introduction

An important semiconductor with huge potential for applications in various areas of nanotechnology has caught researcher’s attention. Because of its great photocatalytic properties, increasing attention has recently been focused on the simultaneous achievement of high specific surface area and the formation of crystalline mesoporous TiO2 frameworks. Many researchers are still focused on mesoporous TiO2 photocatalyst because its textural properties promote the diffusion of reactants to the reactive sites, enhancing the photocatalytic activity [5,6,7]. This evolution has demonstrated that mesoporosity of TiO2 nanoparticles plays an important role in environmental protection. The most common applied process is a solution-based one that is used for making inorganic networks of various nanomaterials through sol-gelation [9]

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