Synthesis of ZnO mesoporous powders and their application in dye photodegradation

Abstract

Mesoporous ZnO materials have been synthesized through chemical deposition of different precursors from aqueous or waterethanol solutions followed by their thermal decomposition at 400°C in air. The microstructure and morphology of the precursors and obtained ZnO powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption-desorption (BET) methods. The structure of the precursor and physico-chemical properties of final zinc oxide powders were shown to be considerably influenced by the presence of Clions and ethanol in solution. In water-ethanol solutions, Zn 5 (OH) 8 Cl 2 •H 2 O or Zn 5 (OH) 8 (NO 3 ) 2 •(H 2 O) 2 precursors are formed, while ZnO particles are directly deposited from aqueous solution. The photocatalytic activity of the synthesized ZnO materials was evaluated by the decolorization of Rhodamine B (RhB) upon UV irradiation. The ZnO powders have demonstrated high photocatalytic efficiency, enabling decomposition of 81.497.4 % RhB within 3 hours. The increased photocatalytic efficiency of ZnO prepared by annealing of Zn 5 (OH) 8 Cl 2 •H 2 O precursor or deposited directly from aqueous chloride-containing solutions can be originated from the presence of Cl-containing compounds remaining after thermal treatment of simonkolleite as well as from introduction of Cl-dopant in ZnO.

Shape-Controlled Synthesis of Coral-like ZnO/C-ZnFe2O4 Hierarchical Structures and Their Improved Photocatalytic Antibacterial Efficiency under Visible Light Illumination

“…In subsequent heat treatment, zinc hydroxide was transformed into crystalline zinc oxide and the ZnFe-alkoxide precursors into zinc ferrite, as can be seen in Figure J–L. Similar experimental phenomena were reported by other researchers …”

“…Similar experimental phenomena were reported by other researchers. 42 To further illustrate the internal structure and crystal characteristics of each sample, the high-resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns were also supplemented, 103), (112), and (201) crystal planes. 43 In the XRD patterns of the as-prepared C-ZFO composites, all of the strong diffraction peaks match with ZnFe 2 O 4 (standard card JCPDS no.…”

Controlled dispersion of ZnO nanoparticles produced by basic precipitation in solvothermal processes

“…In our case the method employed comprises an economical precipitation synthetic route that leads into a mesoporous material enhanced with the combination of solvothermal treatment and ultrasonic irradiation processes, where the exfoliation of mixed ZnO microstructures leads to smaller nanoparticles with high porosity degree. Previous works have reported ZnO nanosized mesoporous materials made under different basic precipitation methods, using different zinc salts as the starting material, but most of them have a distinctive characteristic; the calcination process as the final stage [76,77,78], implying that high temperatures are responsible for the formation of these materials. The method described here differs from all of them by lacking a calcination process, but using ultra cavitation processes the same effect is accomplished, could be the predominant factor in the formation of mesoporous on ZnO surfaces.…”

Synthesis and characterization of mesoporous zinc oxide nanoparticles and evaluation of their biocompatibility in L929 fibroblasts

“…Moreover, ZnO is also a chemically stable, nontoxic, and cheap material (Maltanava, 2018). The key factor for the antibacterial activity of ZnO is its affinity toward the bacterial cell.…”

“…Zinc oxide (ZnO) is well known for its antimicrobial properties and thus has been widely used in various dental materials, such as gutta‐percha, endodontic sealers, zinc polycarboxylate cement, and zinc oxide eugenol (Moradpoor et al, 2021 ; Nozari et al, 2019 ). Moreover, ZnO is also a chemically stable, nontoxic, and cheap material (Maltanava, 2018 ). The key factor for the antibacterial activity of ZnO is its affinity toward the bacterial cell.…”