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Volume 47S Number 1

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Research articles

ScienceAsia 47S (2021): 69-75 |doi: 10.2306/scienceasia1513-1874.2021.S014

Enhanced visible light response of TiO2 nanoparticles by natural dyes

Voranuch Somsongkula,b,*, Prae Chirawatkulc, Chanapa Kongmarkd,*

ABSTRACT:     The visible light responding TiO2 nanoparticles have been achieved through green synthesis method. In this experiment, three types of natural dyes including Turmeric extract, Bergamot fruit extract, and Siamese neem leave extract were used as stabilizing agents. TiO2 nanoparticles were synthesized by solution-based one-step and two-step methods. The results of X-ray diffraction (XRD) and Ti K-edge X-ray absorption near edge structure (XANES) spectroscopy affirmed that anatase TiO2 nanoparticles were obtained from all samples with the average crystallite sizes of 58 nm. Moreover, UV-Visible absorption spectra revealed that the natural dyes play an important role in improving the visible light absorption ability of TiO2 and decreasing the band gap energy of TiO2 from 3.1 eV to 2.3 eV. The absorption edge energies of the two-step samples were lower than those of the one-step samples. The infrared spectra of the two-step TiO2 displayed complex vibration features which were related to the carbonyl (C=O) and hydroxyl (O-H) groups of natural dyes. The presence of these functional groups was obviously responsible for the optical response of TiO2 nanoparticles in the visible wavelength region.

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a Department of Industrial Chemistry, Faculty of Applied Science, King Mongkut?s University of Technology North Bangkok, Bangkok 10800 Thailand
b Integrated Chemistry Research Center for Sustainable Technology (ICRT), King Mongkut?s University of Technology North Bangkok, Bangkok 10800 Thailand
c Synchrotron Light Research Institute (Public Organization), Suranaree University of Technology, Nakhon Ratchasima 30000 Thailand
d Specialized center of Rubber and Polymer Materials in agriculture and industry (RPM), Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900 Thailand

* Corresponding author, E-mail: voranuch.s@sci.kmutnb.ac.th, chanapa.k@ku.th

Received 11 Nov 2020, Accepted 10 Jun 2021