Synthesis, Characterization and Properties of Nanosized Metal Oxide Pigments by a Novel Chemical Method Based on Dioate Precursor

In this work, we report on synthesis, characterization and properties of nanosized copper-based oxide pigments by a novel chemical method based on dioate precursor in mild condition without any templates or additives. The heat treatment of the dioate precursor at 400 °C causes the decomposition of the precursor which generates a nucleus of the crystal at first, and then the crystal grain grows during the thermal treatment to obtain the nanosized material. Dioate compounds perform as reducing agent as well as ligand to form chelates with metal ions. The samples and dioate precursors were evaluated by powder X-ray diffraction (XRD), FT-IR spectroscopy, scanning electron micrographs (SEM), colorimetric analysis using L*a*b* coordinates and diffuse reflectance spectroscopy. The XRD patterns of the samples show peaks assigned to pure single-phase monoclinic particles (space group C2/c) with crystallite sizes in the range of 18-24 nm. FT-IR spectroscopy showed changes in the matrix microstructure and the pore environment of precursors and samples. The spectra display the vibration bands of samples at 603 and 498 cm-1. SEM images showed almost spherical particles which are uniform in both morphology and particle size distribution. Our results confirmed that in this method, metal ions distributed uniformly throughout the organic matrix via dioate precursors which leads to an important decrease of the synthesis temperature and homogeneous mixing at molecular level.