Sprayed Pyrolyzed ZnO Films with Nanoflake and Nanorod Morphologies and Their Photocatalytic Activity

Abstract

There is an increasing interest on the application of ZnO nanorods in photocatalysis and many growth methods have been applied, in particular the spray pyrolysis technique which is attractive for large scale production. However it is interesting to know if the nanorod morphology is the best considering its photocatalytic activity, stability, and cost effectiveness compared to a nonoriented growth. In this work we present a systematic study of the effect of the precursor solution (type of salt, solvent, and concentration) on the morphology of sprayed ZnO films to obtain nanoflakes and nanorods without the use of surfactants or catalysts. The surface properties and structural characteristics of these types of films were investigated to elucidate which morphology is more favorable for photocatalytic applications. Wettability and photocatalytic experiments were carried out in the same conditions. After UV irradiation both morphologies became hydrophilic and achieved a dye discoloration efficiency higher than 90%; however, the nanoflake morphology provided the highest photocatalytic performance (99% dye discoloration) and stability and the lowest energy consumption during the synthesis process. The surface-to-volume ratio revealed that the nanoflake morphology is more adequate for photocatalytic water treatment applications and that the thin nanorods should be preferred over the large ones.

Fabrication and investigation of zinc oxide nanorods doped with molybdenum via ultrasonic spray pyrolysis

“…19,20 In addition, there are some studies in the literature on the production of ZnO nanorods by the spray pyrolysis method. [21][22][23][24] The doping operation takes place in the form of the substitution of the doping ions with Zn 2+ ions which are in the ZnO crystal. When an ion with a higher oxidation state than Zn 2+ enters the crystal, there is an increase in the number of electrons in the crystal, and accordingly, an increase in electrical conductivity occurs.…”

“…Apart from these, the basic structural and morphological properties of the produced materials can be kept under control by adjusting the film growth conditions, so that the grown films gain the necessary functionality for certain applications 19,20 . In addition, there are some studies in the literature on the production of ZnO nanorods by the spray pyrolysis method 21–24 …”

Influence of the Physical Properties on the Antibacterial and Photocatalytic Behavior of Ag-Doped Indium Sulfide Film Deposited by Spray Pyrolysis

“…This is particularly important for industrial production. Spray pyrolysis is also important to produce films for photocatalysis because it is possible to produce films with a high specific surface area (surface area/volume ratio) due to the relatively high roughness of the surface of the produced films [33]. In 2 S 3 thin films deposited by the spray pyrolysis technique have relatively high electrical resistivity.…”

Copper-Doped ZnO Thin Films Deposited by Spray Pyrolysis: Effect of Water Content in Starting Solution on Methylene Blue Degradation by Photocatalysis

“…The precursor or starting solution plays a crucial role in the physical characteristics of the sprayed films. Some of the important parameters of the starting solution that can affect the thin film properties are solution chemistry, 8 precursors, [9][10][11] additives, 12,13 pH, [14][15][16][17][18][19] molarity, 20 doping 21 and solution aging. 22 However, to the best of our knowledge, the effect of water content in the starting solution on the characteristics of sprayed ZnO:Cu films has not been reported.…”