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One-dimensional-like titania/4 '-pentyl-4-biphenylcarbonitrile composite synthesized under magnetic field and its structure-photocatalytic activity relationship

Abu Bakar, Nur I. and Chandren, Sheela and Attan, Nursyafreena and Wai, L. Leaw and Nur, Hadi (2018) One-dimensional-like titania/4 '-pentyl-4-biphenylcarbonitrile composite synthesized under magnetic field and its structure-photocatalytic activity relationship. Frontiers in Chemistry, 6 . pp. 1-13. ISSN 2296-2646

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Official URL: http://dx.doi.org/10.3389/fchem.2018.00370

Abstract

The demonstration of the structure-properties relationship of shape-dependent photocatalysts remains a challenge today. Herein, one-dimensional (1-D)-like titania (TiO2), as a model photocatalyst, has been synthesized under a strong magnetic field in the presence of a magnetically responsive liquid crystal as the structure-aligning agent to demonstrate the relationship between a well-aligned structure and its photocatalytic properties. The importance of the 1-D-like TiO2 and its relationship with the electronic structures that affect the electron-hole recombination and the photocatalytic activity need to be clarified. The synthesis of 1-D-like TiO2 with liquid crystal as the structure-aligning agent was carried out using the sol-gel method under a magnetic field (0.3 T). The mixture of liquid crystal, 4'-pentyl-4-biphenylcarbonitrile (5CB), tetra-n-butyl orthotitanate (TBOT), 2-propanol, and water, was subjected to slow hydrolysis under a magnetic field. The TiO2-5CB took a well-aligned whiskerlike shape when the reaction mixture was placed under the magnetic field, while irregularly shaped TiO2-5CB particles were formed when no magnetic field was applied. It shows that the strong interaction between 5CB and TBOT during the hydrolysis process under a magnetic field controls the shape of titania. The intensity of the emission peaks in the photoluminescence spectrum of 1-D-like TiO2-5CB was lowered compared with the TiO2-5CB synthesized without the magnetic field, suggesting the occurrence of electron transfer from 5CB to the 1-D-like TiO2-5CB during ultraviolet irradiation. Apart from that, direct current electrical conductivity and Hall effect studies showed that the 1-D-like TiO2 composite enhanced electron mobility. Thus, the recombination of electrons and holes was delayed due to the increase in electron mobility; hence, the photocatalytic activity of the 1-D-like TiO2 composite in the oxidation of styrene in the presence of aqueous hydrogen peroxide under UV irradiation was enhanced. This suggests that the 1-D-like shape of TiO2 composite plays an important role in its photocatalytic activity.

Item Type:Article
Uncontrolled Keywords:electron mobility, liquid crystal, magnetic field, one-dimensional-like titania composite, photocatalytic activity
Subjects:Q Science > QD Chemistry
Divisions:Science
ID Code:84517
Deposited By: Yanti Mohd Shah
Deposited On:11 Jan 2020 15:31
Last Modified:11 Jan 2020 15:31

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