Article

Tuning the Optical Properties of ZnO by Co and Gd Doping for Water Pollutant Elimination

Kashif SafeenDepartment of Physics, Abdul Wali Khan University Mardan, Mardan 23200, PakistanAkif SafeenDepartment of Physics, University of Poonch Rawalakot, Rawalakot 12350, PakistanDanish ArifDepartment of Physics, University of Poonch Rawalakot, Rawalakot 12350, PakistanWiqar Hussain ShahDepartment of Physics, International Islamic University H-10, Islamabad 44000, PakistanAkhtar AliDepartment of Physics, International Islamic University H-10, Islamabad 44000, PakistanGhafar AliNanomaterials Research Group, Physics Division, PINSTECH, Islamabad 45650, PakistanFayaz HussainDepartment of Materials Engineering, NED University of Engineering and Technology, Karachi 75270, PakistanNaveed ImranHITEC Schools and Colleges, HIT, Taxila 47070, PakistanAtta Ullah ShahNational Institute of Lasers and Optronics College Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650, PakistanAbed AlatawayPrince Sultan bin Abdulaziz International Prize for Water Chair, Prince Sultan Institute for Environmental, Water and Desert Research, King Saud University, Riyadh 11451, Saudi ArabiaAhmed Z. DewidarDepartment of Agricultural Engineering, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi ArabiaHosam O. ElansaryPlant Production Department, College of Food & Agriculture Sciences, King Saud University, Riyadh 11451, Saudi ArabiaMohamed Al-YafrsiPlant Production Department, College of Food & Agriculture Sciences, King Saud University, Riyadh 11451, Saudi ArabiaKhawaja Shafique AhmadDepartment of Botany, University of Poonch Rawalakot, Rawalakot 12350, Pakistan

2023en

ABI

Abstract

In the present study, pure, Co, Gd, and Co/Gd di-doped ZnO nanoparticles were synthesized via the co-precipitation synthesis route. The prepared samples were characterized through different techniques such as the X-ray diffraction method (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, photoluminescence (PL)spectroscopy, and an impedance analyzer and vibrating sample magnetometer (VSM). The XRD pattern shows ZnO’s wurtzite hexagonal crystal structure; moreover, the shifting of characteristic peaks toward the lower angle indicates the inclusion of Co and Co/Gd in the ZnO host lattice. SEM micrographs show various morphologies such as rods, the agglomeration of particles, and spherical nanoparticles. The UV-Vis spectroscopy reveals that the absorption increased in the visible region and there was a substantial redshift for the doped samples. The bandgap decreased from 3.34 to 3.18 eV for the doped samples. The PL spectra show near-edge and inter-band transitions; the origin of inter-band transitions is attributed to the defect states present within the bands. The dielectric constant is strongly frequency dependent and decreases with Co and Co/Gd doping, while the electrical conductivity increases. A VSM study indicates that pure ZnO is diamagnetic, while the Co and Co/Gd doped ZnO nanoparticles showed ferromagnetic behavior. Under UV-visible light irradiation, the Co/Gd-ZnO nanoparticles showed higher photocatalytic activity than the ZnO nanoparticles. The enhanced photocatalytic activity may be attributed to a decreased bandgap with doping.

Identifiers

DOI: 10.3390/w15081470

Citations and references

Cited by 20 references

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