Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides

Hollow titania (TiO2) materials have unique properties, such as multiple light reflection and diffraction, surface permeability, light-harvesting capability and their technological importance in the fields of medicine, pharmacy, materials science, water treatment, catalyst and photocatalyst. The res...

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Main Author:	Baharvand, Afrouz
Format:	Thesis
Language:	English
Published:	2015
Subjects:	QD Chemistry
Online Access:	http://eprints.utm.my/id/eprint/54849/1/AfrouzBaharvandPFS2015.pdf
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spelling	my-utm-ep.548492020-11-09T06:05:05Z Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides 2015-11 Baharvand, Afrouz QD Chemistry Hollow titania (TiO2) materials have unique properties, such as multiple light reflection and diffraction, surface permeability, light-harvesting capability and their technological importance in the fields of medicine, pharmacy, materials science, water treatment, catalyst and photocatalyst. The research described in this dissertation is a comprehensive account of an attempt to correlate structural and physicochemical properties of hollow TiO2 microspheres containing silver (Ag) and gold (Au) nanoparticles with their photocatalytic properties. It is hypothesized that hollow TiO2 microspheres containing Ag and Au nanoparticles can enhance light harvesting and also facilitates the charge separation, in the photodegradation of pesticides. The location of Ag and Au, whether inside or outside the hollow titania, may also affect the photocatalytic activity. The synthesis of hollow TiO2 microspheres containing Ag or Au nanoparticles was conducted by using fructose as the precursor via hydrothermal method. The fructose-derived carbonaceous spheres obtained were then used as the template for the synthesis of hollow crystalline TiO2 microspheres photocatalysts. These photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance ultraviolet–visible (DR UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, thermogravimetry (TG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and chemical analysis by X-ray fluoresence (XRF) spectroscopy. TiO2 photocatalyst obtained was in the crystalline anatase phase and spherical in shape, with cavity inside the spheres. The existence of Ag and Au was confirmed by XRD, XRF, EDX, TEM and HRTEM. DR UV–Vis spectra revealed that the hollow TiO2 containing noble metals have absorption spectrum in a longer wavelength in comparison to that of commercial TiO2. By employing pesticides, namely paraquat dichloride, diazinon, imazalil sulfate, atrazine, lindane and chlorpyrifos, as the target compounds, the photocatalytic activity investigation of the hollow TiO2 microspheres was carried out. The photodegradation of pesticides over hollow TiO2 microspheres containing Ag or Au nanoparticles was correlated with the type of pesticides in the following decreasing order: chlorpyrifos ? diazinon ? ?lindane ? imazalil sulphate ? paraquat dichloride ? atrazine. It was also observed that the location of Ag or Au, whether inside or outside the microspheres, is an important factor to achieve high photocatalytic activity for the decomposition of pesticides. The photocatalytic activity results revealed that the attachment of Ag nanoparticles outside the TiO2 microspheres was the most effective location in the photodegradation of these pesticides, with 84% degraded. Based on the above results, it is suggested that the location of the Ag or Au as electron scavengers on the hollow TiO2 microspheres plays an important role in the photocatalytic activities of these materials. 2015-11 Thesis http://eprints.utm.my/id/eprint/54849/ http://eprints.utm.my/id/eprint/54849/1/AfrouzBaharvandPFS2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:96102 phd doctoral Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Baharvand, Afrouz Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
description	Hollow titania (TiO2) materials have unique properties, such as multiple light reflection and diffraction, surface permeability, light-harvesting capability and their technological importance in the fields of medicine, pharmacy, materials science, water treatment, catalyst and photocatalyst. The research described in this dissertation is a comprehensive account of an attempt to correlate structural and physicochemical properties of hollow TiO2 microspheres containing silver (Ag) and gold (Au) nanoparticles with their photocatalytic properties. It is hypothesized that hollow TiO2 microspheres containing Ag and Au nanoparticles can enhance light harvesting and also facilitates the charge separation, in the photodegradation of pesticides. The location of Ag and Au, whether inside or outside the hollow titania, may also affect the photocatalytic activity. The synthesis of hollow TiO2 microspheres containing Ag or Au nanoparticles was conducted by using fructose as the precursor via hydrothermal method. The fructose-derived carbonaceous spheres obtained were then used as the template for the synthesis of hollow crystalline TiO2 microspheres photocatalysts. These photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance ultraviolet–visible (DR UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, thermogravimetry (TG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and chemical analysis by X-ray fluoresence (XRF) spectroscopy. TiO2 photocatalyst obtained was in the crystalline anatase phase and spherical in shape, with cavity inside the spheres. The existence of Ag and Au was confirmed by XRD, XRF, EDX, TEM and HRTEM. DR UV–Vis spectra revealed that the hollow TiO2 containing noble metals have absorption spectrum in a longer wavelength in comparison to that of commercial TiO2. By employing pesticides, namely paraquat dichloride, diazinon, imazalil sulfate, atrazine, lindane and chlorpyrifos, as the target compounds, the photocatalytic activity investigation of the hollow TiO2 microspheres was carried out. The photodegradation of pesticides over hollow TiO2 microspheres containing Ag or Au nanoparticles was correlated with the type of pesticides in the following decreasing order: chlorpyrifos ? diazinon ? ?lindane ? imazalil sulphate ? paraquat dichloride ? atrazine. It was also observed that the location of Ag or Au, whether inside or outside the microspheres, is an important factor to achieve high photocatalytic activity for the decomposition of pesticides. The photocatalytic activity results revealed that the attachment of Ag nanoparticles outside the TiO2 microspheres was the most effective location in the photodegradation of these pesticides, with 84% degraded. Based on the above results, it is suggested that the location of the Ag or Au as electron scavengers on the hollow TiO2 microspheres plays an important role in the photocatalytic activities of these materials.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Baharvand, Afrouz
author_facet	Baharvand, Afrouz
author_sort	Baharvand, Afrouz
title	Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
title_short	Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
title_full	Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
title_fullStr	Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
title_full_unstemmed	Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
title_sort	synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2015
url	http://eprints.utm.my/id/eprint/54849/1/AfrouzBaharvandPFS2015.pdf
_version_	1747817740711755776

Synthesis, characterization and application of hollow titania microspheres containing silver and gold nanoparticles in the photodegradation of pesticides

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