Boosting the sunlight irradiation and methylene blue dye degradation over ZnO doped with N and C elements

Document Type : Original Article

Authors

1 Department of Chemistry, Faculty of Science, Menoufia University,

2 King Abdulaziz University, Science & Art College

3 Physical Chemistry, Inorganic chemical industries division, National Research Centre,

4 Department of Chemistry, Faculty of Science, Menoufia University

Abstract

This article aims to preparing of ZnO nanoparticles and doping with nitrogen (N) and carbon (C) nonmetals via sol-gel method followed during the calcination in N2 and air media to mitigate the fast electron-hole pairs recombination drawbacks and improve the visible light photocatalytic activity of pure ZnO under sunlight irradiation. The influence of dopant content of N- and C-N doped ZnO on the photodegradation of methylene blue (MB) dye was investigated. To compare doped samples properties with ZnO bare, techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), fourier transform infrared (FTIR), Brunauer, Emmett and Teller (BET) surface area, and UV-Vis diffuse reflectance spectroscopy (DRS) were employed. Wurtize hexagonal structure of ZnO with good crystallinity of nanoparticles (NPs) ranged between 15.5 and 45.8 nm was confirmed by XRD. However, entering N into ZnO lattice decreased the crystallite size whereas doping with C-N enhanced the crystallite size of ZnO. Through SEM, ZnO NPs appeared as spherical morphology and FTIR showed the characteristic absorption bands related to Zn–O stretching and bending vibration modes with symmetric stretching vibration of O–C=O and–C–O groups were detected in FTIR. The bandgap value of ZnO was decreased from 3.07eV to 2.83eV upon doping with 40%N/ZnO(air). Pure ZnO exhibited 100% degradation of MB at 180 min, and ZnO doped with the highest concentrations of N and C-N dopants showed full degradation of MB dye at 60 and 90 min, respectively. Thereof, the 40% N/ ZnO(air) material exhibited the higher visible-light activity compared with 40%C-N/ZnO(N2), where complete MB dye photodegradation was obtained at 60min.This superior photoactivity for 40%N/ZnO catalyst is due to their capability in reducing the electron–hole pair recombination arising from its smaller bandgap energy value.

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Egyptian Journal of Chemistry
Volume 66, Issue 13 - Serial Number 13
Special Issue: Applied Chemistry for Greener Life and Sustainability
December 2023
Pages 1133-1140

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History

  • Receive Date: 09 April 2023
  • Revise Date: 29 April 2023
  • Accept Date: 01 May 2023

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