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Easy and Fast Obtention of ZnO by Thermal Decomposition of Zinc Acetate and Its Photocatalytic Properties over Rhodamine B Dye

Authors :
Dalete Araujo de Souza
Pedro Hyug de Almeida da Silva
Francisco Paulino da Silva
Yonny Romaguera-Barcelay
Robson Dantas Ferreira
Edgar Alves Araujo Junior
José Fábio de Lima Nascimento
Fagner Ferreira da Costa
Litiko Lopes Takeno
Yurimiler Leyet Ruiz
Lianet Aguilera Dominguez
Walter Ricardo Brito
Francisco Xavier Nobre
Source :
Colorants, Vol 3, Iss 3, Pp 229-252 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

This study presents a simple, low-cost, and efficient route to obtain zinc oxide by adopting the thermal decomposition method of zinc acetate at 300 (Gr@ZnO_300), 400 (Gr@ZnO_400), 500 (Gr@ZnO_500), and 600 °C (Gr@ZnO_600) for 1 h. The diffraction patterns collected for the samples indicated the majority formation of the hexagonal phase (P63mc) for zinc oxide and residual amounts for graphitic carbon, which has a hexagonal structure of space group P63/mmc. The images collected by scanning electron microscopy (SEM) revealed the formation of sub-microcrystals with elongated rod-shaped morphology, with dimensions between 0.223 and 1.09 μm. The optical and colourimetric properties of the obtained materials indicate the presence of graphitic carbon in the samples, corroborating the analysis by XRD and Raman spectroscopy, with an optical bandgap close to 3.21 eV, and energies of the valence (EVB) and conduction (ECB) bands of 2.89 eV and −0.31 eV, respectively. The photocatalytic performance at 20 min of exposure time under UV light of all prepared samples in the decolourisation of rhodamine B (RhB) dye solutions follows the order Gr@ZnO_300 (95.6%) > Gr@ZnO_600 (92.8%) > Gr@ZnO_400 (84.0%) > Gr@ZnO_500 (78.1%), where the photocatalytic performance of Gr@ZnO_300 sample was 16.5 times more effective than the photolysis test. Moreover, the results confirmed that the best performance was archived at pH = 10, and the holes (h+) and superoxide (O2•−) radicals are the main species involved in the discolouration of RhB dye molecules in an aqueous medium. Finally, the reusability experiment shows high stability of the Gr@ZnO_300 sample as a solid photocatalyst and cycling capability, which obtained total discolouration of RhB of a solution under five cycling experiments of 60 min of exposure to UV light at room temperature.

Details

Language :
English
ISSN :
20796447
Volume :
3
Issue :
3
Database :
Directory of Open Access Journals
Journal :
Colorants
Publication Type :
Academic Journal
Accession number :
edsdoj.707381e58a5c46fcaeb1ae2455d98197
Document Type :
article
Full Text :
https://doi.org/10.3390/colorants3030016