Influences of a new templating agent on the synthesis of coral-like TiO 2 nanoparticles and their photocatalytic activity

Satwant Kaur Shahi,Sofia Sandhu,Vasundhara Singh,Navneet Kaur,J.S Shahi

doi:10.1016/j.jsamd.2017.07.006

Abstract

Abstract We report a low cost and environmentally-friendly solvent system to synthesize TiO2 nanoparticles using an acidic deep eutectic solvent, choline chloride/p-toluene sulphonic acid as a templating and hydrolyzing agent via sol–gel method. The effect of varying concentration of the deep eutectic solvent (DES) on the important physico-chemical characteristics of as-synthesized TiO2 such as phase, morphology, particle size, surface area and band gap energy was studied. A detailed characterization of the obtained nanomaterials has been performed using various techniques, including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, Raman and Ultraviolet–visible absorption spectroscopy. The spherical TiO2 nanoparticles were found to be biphasic with two phases: anatase and rutile having crystallite sizes in the range of 5.6–6.8 nm. These nanoparticles assembled together to form a coral-like morphology. The effect of calcination temperature on the synthesized products was studied by heating at 750 °C. The photocatalytic activity of the prepared TiO2 materials was evaluated by the photo-discoloration of an aqueous methyl orange dye solution (20 ppm) under UV light irradiation. The results indicate that the photocatalytic efficiency of an anatase–rutile mixture in the optimal sample DES-3 is higher (98% within 3 h) than a commercially available Degussa P-25 (87% within 3 h).

Highlights

Titanium dioxide has attracted vast attention because of its widespread technological applications in photocatalysis, photovoltaics, gas sensors, self-cleaning surfaces, white pigments, catalyst supports, lithium ion batteries, memory devices and so on [ 1-5]
2.1 Reagents and Chemicals All chemicals used in this work, tetra butyl titanate (TBT) ((Ti(OCH2CH2CH2CH3)4, 97%)), choline chloride ((CH3)3N(Cl)CH2CH2OH, 99%)), para toluene sulphonic acid (CH3C6H4SO3H, 98.5%), ethanol, Degussa P-25 (99.5%) and methyl orange were of analytical purity grade, supplied by Sigma-Aldrich and were used as received without any further purification. 2.2 Preparation of acidic deep eutectic solvents (DES)
X-ray diffraction (XRD) patterns showed the variation between anatase (101) and rutile (110) phases with change in concentration of acidic DES

Summary

Introduction

Titanium dioxide has attracted vast attention because of its widespread technological applications in photocatalysis, photovoltaics, gas sensors, self-cleaning surfaces, white pigments, catalyst supports, lithium ion batteries, memory devices and so on [ 1-5]. TiO2 can exist in three distinct phases: anatase, rutile and brookite. It is well known that the performance of TiO2 in various applications and its physico-chemical properties are strongly influenced by its particle size, phase, morphology and surface area [12, 13]. It is desirable to develop nanostructures via various synthetic routes that allow for controlling the phase structure, size and morphology of TiO2 in good yield on the nanoscale. Controllable synthesis of TiO2 has gained much attention and variety of structures have been reported [14,15,16,17,18,19]. Various methods have been explored to synthesize TiO2 nanomaterials such as sol-gel, precipitation, hydrothermal, microwave assisted, chemical vapour deposition and sonochemical method

Methods

Results

Conclusion