Preparation, Characterisation and Photocatalytic Activity of La-doped ZnO Nanopowders Synthesised using Auto-combustion

Mukhtar Ahmad; Eijaz Ahmed; Muhammad Ikram; Fezza Zafar; Niaz Ahmed Niaz; Zhanglian Hong; Abdul Hafeez; Khalid Nadeem Riaz; Waqar Ahmed

doi:10.52763/PJSIR.PHYS.SCI.59.1.2016.1.10

Mukhtar Ahmad Department of Physics, Bahauddin Zakariya University, Multan 60800, Pakistan
Eijaz Ahmed Department of Physics, Bahauddin Zakariya University, Multan 60800, Pakistan
Muhammad Ikram Department of Physics, Bahauddin Zakariya University, Multan 60800, Pakistan
Fezza Zafar Department of Physics, Bahauddin Zakariya University, Multan 60800, Pakistan
Niaz Ahmed Niaz Department of Physics, Bahauddin Zakariya University, Multan 60800, Pakistan
Zhanglian Hong bState Key Laboratory of Silicon Materials, Department of Materials Science & Engineering, Zhejiang University, Hangzhou 310027, China
Abdul Hafeez Science and Technology Division, University of Education, Lahore, Pakistan
Khalid Nadeem Riaz Department of Physics, University of Gujrat, Gujrat 50700, Pakistan
Waqar Ahmed Institute of Nanotechnology and Bioengineering, University of Central Lancashire, School of Medicine, Preston PR1 2HE, United Kingdom

DOI: https://doi.org/10.52763/PJSIR.PHYS.SCI.59.1.2016.1.10

Keywords: ZnO, combustion, XRD, photocatalysis, methyl orange, La-doped ZnO

Abstract

Nanocrystalline nanoparticles of pristine ZnO and La-doped ZnO have been synthesised using
a combustion method using various concentrations of lanthanum dopant followed by calcination for 3 h
at 700 °C. The crystalline structure, chemical composition and optical characteristics have been characterised
using X-ray diffraction (XRD), scanning electron spectroscopy (SEM) attached with energy dispersive
X-ray (EDX) spectroscopy, Brunauer Emmett Teller (BET), UV-vis. spectroscopy and photoluminescence
(PL) spectroscopy. Absorption spectra showed that the absorbance increased with La-doping and the blue
shift observed was due to an increase in the band gap from 3.24 to 3.27 eV. The photocatalytic activities
of the samples prepared were evaluated using the photocatalytic degradation of methyl orange (MO) under
irradiation by sunlight. The textile mill effluents containing organic matter were also irradiated with sunlight
inducing photocatalysis and the chemical oxygen demand (COD) of the treated effluent were investigated.
The results showed that the ZnO photocatalyst doped with 1.0 at.% lanthanum exhibited four times
enhancement in the photocatalytic activity compared to pure ZnO.