Synthesis of Titania/Silica Nanocomposite for Enhanced Photodegradation of Methylene Blue and Methyl Orange Dyes under UV and Mercury Lights

Ruchi Nandanwar,1

Jyoti Bamne,2

Nitu Singh,2

P. K. Sharma,2

Purnima Singh,1

Ahmad Umar3,4 

Fozia Z. Haque5*Email

1Department of Physics, Sarojini Naidu Govt. Girls Autonomous P.G. College, Bhopal-462016, Madhya Pradesh, India

2Department of Applied Physics, Barkatullah University Institute of Technology (BUIT), Bhopal-462003, Madhya Pradesh, India

3 Department of Chemistry, Faculty of Science and Arts, Najran University, Najran-11001, Kingdom of Saudi Arabia

4 Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, Najran-11001, Kingdom of Saudi Arabia

5Optical Nanomaterials Lab., Department of Physics, Maulana Azad National Institute of Technology (M.A.N.I.T.), Bhopal 462003, Madhya Pradesh, India

Abstract

A special sol-gel method is used to successfully synthesize spherical TiO2/SiO2 nanoparticles from titanium tetra-isopropoxide and tetraethoxysilane precursors. The prepared samples were dried at 110 °C and calcined at 300 °C, 500 °C and 800 °C. The formed titanium oxide is in a tetragonal structure with significant pure anatase and rutile phase. The estimated particle size of spherical nanostructure was ~18.40 nm through transmission electron microscopy (TEM) and showed a larger Brunauer Emmett Teller (BET) surface area of 310 m2/gm for the sample calcined at 300 oC. The TiO2 cores are enclosed within SiO2 particles with an average crystallite size of 10-20 nm. In atomic force microscopy (AFM) images, the same sample displayed the well-structured and macro-pore free morphology. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of Ti-O-Ti, Si-O-Si and Ti-O-Si metal oxide bond to raise anatase structure of TiO2. The ultraviolet visible spectroscopy (UV-Vis) of as synthesized samples revels the visible absorption region. Photoluminescence spectroscopy (PL) shows a decrease in emission intensity and the emission band splits into sharp peaks to signify the decrease in recombination rate. These properties predict the materials to photo-degrade organic dyes. The material’s photocatalytic activity was evaluated for degradation of methylene blue and methyl orange dyes. It is found that the sample calcined at 300 °C exhibits a better photodegradation for methylene blue (MB, 80-85%) than methyl orange (MO, 70-75%) under mercury light within 2 hours.

Synthesis of Titania/Silica Nanocomposite for Enhanced Photodegradation of Methylene Blue and Methyl Orange Dyes under UV and Mercury Lights