Effect of Microwave Radiation Power on the Size of Aggregates of ZnO NPs Prepared Using Microwave Solvothermal Synthesis

Abstract

This paper reports the possibility of changing the size of zinc oxide nanoparticles (ZnO NPs) aggregates through a change of synthesis parameters. The effect of the changed power of microwave heating on the properties of ZnO NPs obtained by the microwave solvothermal synthesis from zinc acetate dissolved in ethylene glycol was tested for the first time. It was found that the size of ZnO aggregates ranged from 60 to 120 nm depending on the power of microwave radiation used in the synthesis of ZnO NPs. The increase in the microwave radiation power resulted in the reduction of the total synthesis time with simultaneous preservation of the constant size and shape of single ZnO NPs, which were synthesized at a pressure of 4 bar. All the obtained ZnO NPs samples were composed of homogeneous spherical particles that were single crystals with an average size of 27 ± 3 nm with a developed specific surface area of 40 m2/g and the skeleton density of 5.18 ± 0.03 g/cm3. A model of a mechanism explaining the correlation between the size of aggregates and the power of microwaves was proposed. This method of controlling the average size of ZnO NPs aggregates is presented for the first time and similar investigations are not found in the literature.

Current Trends in the Development of Microwave Reactors for the Synthesis of Nanomaterials in Laboratories and Industries: A Review

“…Using glycerol as the reaction medium, a metallic copper powder was produced from copper hydroxide (the phenomenon of melting copper particles into large balls, which led to ERTEC reactor failure, was observed). Furthermore, this research proved that microwave solvothermal synthesis enables us to control the size of the ZnO NPs aggregates within the range from 60 nm to 120 nm, at the same time preserving the constant size of single ZnO NPs (≈27 nm) ( Figure 8) [55].…”

ZnO as a Functional Material, a Review

“…Further changes can be done by exchanging thermal heating to microwave heating in an embodiment called microwave solvothermal (hydrothermal) synthesis. The main advantage of this technique is in the higher efficiency of heating using microwaves than in the case of conventional heat transfer through conduction and convection while keeping higher uniformity and shorter reaction times [120]. Sonochemical synthesis is another variation of the solvothermal method of ZnO nanostructure formation that utilizes ultrasound mixing of the constituents of a typical solvothermal solution through bubble formation and cavitation [121].…”

Synthesis of Chitosan/Zinc Oxide Nanoparticles Stabilized by Chitosan via Microwave Heating

“…The temperature of chitosan/ZnO nanoparticles samples was risen rapidly during the process and drops gradually after the process. Wojnarowicz et al [31] stated that increasing the heating time could increase the temperature of chitosan/ZnO nanoparticles which may be reached up to the boiling point of the solution.…”