Hydrothermal Synthesis of CuO Nanoparticles: Study on Effects of Operational Conditions on Yield, Purity, and Size of the Nanoparticles

Abstract

Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of “yield”, “purity”, and “size of the nanoparticles” that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm−3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the mechanisms of effects of operational conditions (e.g., temperature) on the above-mentioned target parameters, through application of the appropriate mechanisms of formation of nanoparticles. Nanoparticles are suggested to form initially in the liquid phase as Cu(OH)2, which are later transformed to Cu2(OH)3NO3, through which CuO product is obtained. Decomposition of nitric acid also plays role in this mechanism. Fabricated nanoparticles are effective catalysts for the synthesis of benzoheterocycle compounds in the pharmaceutical industries.

An investigation into the formation and conversion of metal complexes to metal oxide nanoparticles in supercritical water

“…Therefore, one can conclude that the metal nitrate salts are good candidates to be used as precursors. On the other hand, our findings indicated that the formation of some nitrate, hydroxide, or hydoxinitrates complexes as the byproducts of metal oxide formation reaction is unavoidable [16,29]. The existence of such…”

Sonochemical synthesis of CuO nanostructures and their morphology dependent optical and visible light driven photocatalytic properties

“…There are several synthesis routes such as solution based technique [15], hydrothermal [16], microwave [17] and ultrasonics [18] have been developed to prepare well-defined nanostructures with different morphologies. The size, shape and morphology of the CuO nanostructures are greatly affected by various parameters such as concentration of constituents, temperature and aging time [15,19,20].…”

Continuous production of CuO nanoparticles in a rotating packed bed

“…Some recently reported methods for preparing CuO nanoparticles include the hydrothermal method [3,11], the precipitation method [4,5,7,8], the sol-gel method [12], the flame spray pyrolysis method [13], and solution combustion method [9]. Of these schemes, the precipitation method is particularly simple, and has attracted considerable interest from industry owing to its low required energy and temperature, and cost-effectiveness in large-scale production with high yield [14][15][16][17].…”