Photocatalytic degradation of P-Cresol using TiO2/ZnO hybrid surface capped with polyaniline

Thabo J. Brooms, Benton Otieno, Maurice S. Onyango, Aoyi Ochieng

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

This study evaluated the photocatalytic activity of polyaniline (PANI)-capped titanium dioxide and zinc oxide (TiO2/ZnO) hybrid, for the degradation of P-Cresol. The hybrid was synthesized by precipitating ZnO on the surface of commercial TiO2. An “in situ” chemical oxidative polymerization method was used to prepare the PANI capped hybrid (TiO2/ZnO/PANI). The photocatalysts were characterized by powder X-ray diffraction (XRD), a Brunauer Emmett Teller (BET) analyzer, Fourier-transform infrared (FTIR) and photoluminescence spectroscopies, high resolution-transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). During photodegradation under ultraviolet (UV) irradiation, ZnO, TiO2, TiO2/ZnO hybrid and TiO2/ZnO/PANI composite had P-Cresol removal of 43%, 50%, 61% and 99%, respectively. The higher activity of the TiO2/ZnO hybrid as compared to TiO2 and ZnO was attributed to a reduced electron–hole pair recombination. The recombination was further significantly reduced upon introduction of PANI; hence, the highest activity observed with TiO2/ZnO/PANI. The initial reaction rate constant for TiO2/ZnO/PANI (0.9679 min−1) was more than twice compared to that for TiO2/ZnO hybrid (0.1259 min−1). A synergistic effect between PANI and TiO2/ZnO resulted in a highly efficient charge separation caused by the transfer of photogenerated holes from the hybrid to highest occupied molecular orbitals (HOMO) of PANI. The best TiO2/ZnO/PANI (PANI to TiO2/ZnO) ratio observed was 0.5:2 for the photodegradation of P-Cresol. Total organic carbon (TOC) analysis indicated a 97.4% mineralization of P-Cresol with PANI/TiO2/ZnO.
Original languageEnglish
Pages (from-to)99-107
Number of pages9
JournalJournal of Environmental Science and Health - Part A Environmental Science and Engineering
Volume53
Issue number20
DOIs
Publication statusPublished - 2017

Fingerprint

Polyaniline
Degradation
Photodegradation
Photoluminescence spectroscopy
Molecular orbitals
Photocatalysts
High resolution transmission electron microscopy
Organic carbon
Zinc oxide
X ray powder diffraction
Titanium dioxide
Reaction rates
Fourier transform infrared spectroscopy
Thermogravimetric analysis
Rate constants
Polymerization
Irradiation

Cite this

@article{538a5e45095c4941ba5f26d989e25aee,
title = "Photocatalytic degradation of P-Cresol using TiO2/ZnO hybrid surface capped with polyaniline",
abstract = "This study evaluated the photocatalytic activity of polyaniline (PANI)-capped titanium dioxide and zinc oxide (TiO2/ZnO) hybrid, for the degradation of P-Cresol. The hybrid was synthesized by precipitating ZnO on the surface of commercial TiO2. An “in situ” chemical oxidative polymerization method was used to prepare the PANI capped hybrid (TiO2/ZnO/PANI). The photocatalysts were characterized by powder X-ray diffraction (XRD), a Brunauer Emmett Teller (BET) analyzer, Fourier-transform infrared (FTIR) and photoluminescence spectroscopies, high resolution-transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). During photodegradation under ultraviolet (UV) irradiation, ZnO, TiO2, TiO2/ZnO hybrid and TiO2/ZnO/PANI composite had P-Cresol removal of 43{\%}, 50{\%}, 61{\%} and 99{\%}, respectively. The higher activity of the TiO2/ZnO hybrid as compared to TiO2 and ZnO was attributed to a reduced electron–hole pair recombination. The recombination was further significantly reduced upon introduction of PANI; hence, the highest activity observed with TiO2/ZnO/PANI. The initial reaction rate constant for TiO2/ZnO/PANI (0.9679 min−1) was more than twice compared to that for TiO2/ZnO hybrid (0.1259 min−1). A synergistic effect between PANI and TiO2/ZnO resulted in a highly efficient charge separation caused by the transfer of photogenerated holes from the hybrid to highest occupied molecular orbitals (HOMO) of PANI. The best TiO2/ZnO/PANI (PANI to TiO2/ZnO) ratio observed was 0.5:2 for the photodegradation of P-Cresol. Total organic carbon (TOC) analysis indicated a 97.4{\%} mineralization of P-Cresol with PANI/TiO2/ZnO.",
author = "Brooms, {Thabo J.} and Benton Otieno and Onyango, {Maurice S.} and Aoyi Ochieng",
year = "2017",
doi = "10.1080/10934529.2017.1377583",
language = "English",
volume = "53",
pages = "99--107",
journal = "Journal of Environmental Science and Health - Part A Environmental Science and Engineering",
issn = "0360-1226",
publisher = "Dekker",
number = "20",

}

Photocatalytic degradation of P-Cresol using TiO2/ZnO hybrid surface capped with polyaniline. / Brooms, Thabo J.; Otieno, Benton; Onyango, Maurice S.; Ochieng, Aoyi.

In: Journal of Environmental Science and Health - Part A Environmental Science and Engineering, Vol. 53, No. 20, 2017, p. 99-107.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Photocatalytic degradation of P-Cresol using TiO2/ZnO hybrid surface capped with polyaniline

AU - Brooms, Thabo J.

AU - Otieno, Benton

AU - Onyango, Maurice S.

AU - Ochieng, Aoyi

PY - 2017

Y1 - 2017

N2 - This study evaluated the photocatalytic activity of polyaniline (PANI)-capped titanium dioxide and zinc oxide (TiO2/ZnO) hybrid, for the degradation of P-Cresol. The hybrid was synthesized by precipitating ZnO on the surface of commercial TiO2. An “in situ” chemical oxidative polymerization method was used to prepare the PANI capped hybrid (TiO2/ZnO/PANI). The photocatalysts were characterized by powder X-ray diffraction (XRD), a Brunauer Emmett Teller (BET) analyzer, Fourier-transform infrared (FTIR) and photoluminescence spectroscopies, high resolution-transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). During photodegradation under ultraviolet (UV) irradiation, ZnO, TiO2, TiO2/ZnO hybrid and TiO2/ZnO/PANI composite had P-Cresol removal of 43%, 50%, 61% and 99%, respectively. The higher activity of the TiO2/ZnO hybrid as compared to TiO2 and ZnO was attributed to a reduced electron–hole pair recombination. The recombination was further significantly reduced upon introduction of PANI; hence, the highest activity observed with TiO2/ZnO/PANI. The initial reaction rate constant for TiO2/ZnO/PANI (0.9679 min−1) was more than twice compared to that for TiO2/ZnO hybrid (0.1259 min−1). A synergistic effect between PANI and TiO2/ZnO resulted in a highly efficient charge separation caused by the transfer of photogenerated holes from the hybrid to highest occupied molecular orbitals (HOMO) of PANI. The best TiO2/ZnO/PANI (PANI to TiO2/ZnO) ratio observed was 0.5:2 for the photodegradation of P-Cresol. Total organic carbon (TOC) analysis indicated a 97.4% mineralization of P-Cresol with PANI/TiO2/ZnO.

AB - This study evaluated the photocatalytic activity of polyaniline (PANI)-capped titanium dioxide and zinc oxide (TiO2/ZnO) hybrid, for the degradation of P-Cresol. The hybrid was synthesized by precipitating ZnO on the surface of commercial TiO2. An “in situ” chemical oxidative polymerization method was used to prepare the PANI capped hybrid (TiO2/ZnO/PANI). The photocatalysts were characterized by powder X-ray diffraction (XRD), a Brunauer Emmett Teller (BET) analyzer, Fourier-transform infrared (FTIR) and photoluminescence spectroscopies, high resolution-transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). During photodegradation under ultraviolet (UV) irradiation, ZnO, TiO2, TiO2/ZnO hybrid and TiO2/ZnO/PANI composite had P-Cresol removal of 43%, 50%, 61% and 99%, respectively. The higher activity of the TiO2/ZnO hybrid as compared to TiO2 and ZnO was attributed to a reduced electron–hole pair recombination. The recombination was further significantly reduced upon introduction of PANI; hence, the highest activity observed with TiO2/ZnO/PANI. The initial reaction rate constant for TiO2/ZnO/PANI (0.9679 min−1) was more than twice compared to that for TiO2/ZnO hybrid (0.1259 min−1). A synergistic effect between PANI and TiO2/ZnO resulted in a highly efficient charge separation caused by the transfer of photogenerated holes from the hybrid to highest occupied molecular orbitals (HOMO) of PANI. The best TiO2/ZnO/PANI (PANI to TiO2/ZnO) ratio observed was 0.5:2 for the photodegradation of P-Cresol. Total organic carbon (TOC) analysis indicated a 97.4% mineralization of P-Cresol with PANI/TiO2/ZnO.

U2 - 10.1080/10934529.2017.1377583

DO - 10.1080/10934529.2017.1377583

M3 - Article

VL - 53

SP - 99

EP - 107

JO - Journal of Environmental Science and Health - Part A Environmental Science and Engineering

JF - Journal of Environmental Science and Health - Part A Environmental Science and Engineering

SN - 0360-1226

IS - 20

ER -