Combustion Synthesis of CuO Nanomaterials: Effect of Different Fuels on the Structural, Thermal, and Optical Properties

Abstract

The wet chemical combustion synthesis and the effect of different (aniline, citric acid monohydrate, dextrose, glycine, hexamine, oleic acid, sucrose, and urea) fuels on the combustion products of CuO nanomaterials are reported for the first time as a comparative study. The pure nano-sized CuO phase combustion products were produced from hexamine, urea, and glycine as fuels, whereas fuel-like sucrose yielded nearly a single phase of the CuO combustion product. The quality of the combustion products revealed mixed phases of CuO and Cu2O for aniline, dextrose, citric acid monohydrate, and oleic acid as fuels. The pure combustion products crystallized in a monoclinic structure with a space group, C12/c1 (15). For the mixed phases of combustion products, weight gain (102.5%–109%) is noted >400 °C in the TG curves owing to the oxidation of the Cu2O phase into the CuO phase. The bandgap of the different CuO powder was in the range of 2.1–2.6 eV. From the NIR spectra, we conclude that the nanocrystallinty of the CuO phase plays a major role in the enhancement (∼35%) of NIR reflectance owing to the difference in the fuels used. The observed Raman modes confirm the characteristics of the CuO phase. Different morphologies are observed for the different CuO combustion products obtained from hexamine, urea, and glycine as fuels.