Synthesis of copper chromite nanoparticles by co-precipitation methodand and study of the effect of Cu(II)/Cr(III) mole ratio, temperature and surfactant on the structure, morphology and size of it

In this work, we used co-precipitation method for synthesis of coper chromite(CuCr2O4.CuO). Three mole ratios of Cu2ﰪ (0.4, 0.7 and1.0) was used in order to investigate the effect of these mole ratios on the phase, morphology and size of particles. Precursor samples were calcined at 500, 600 and 700ºC for each mole ratio in order to investigate the effect of calcination temperatures. Furthermore two samples were calcined at 800 and 900 ºC and two samples synthesized in the presence of sodium dodecyl sulphate as surfactant at 700 ºC. All samples were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) analysis. XRD patterns of nanoparticles calcined at 500, 600 and 700ºC revealed that, at this range of temperature, nanoparticles have been composed of CuCr2O4 spinel and CuO. Furthermore XRD patterns showed that by changing mole ratio of Cu2ﰪ the amount of CuO remains constant at 500 and 600 ºC calcination temperatures but at higher temperature (700 ºC) the amount of CuO increases by increasing mole ratio of Cu2ﰪ. At 800 and 900 ºC calcination temperatures and Cu2ﰪ =1, CuCr2O4 spinel was not seen, this compound reacts with CuO and produces CuCrO2 at these temperatures.
SEM images of nanoparticles at 500, 600 and 700ºC calcination temperatures showed that the morphology of nanoparticles is almost like nanosheet with a thickness in the range of 20-35 nm. Big aggregation is seen due to small particle size. The best nanoparticle according to uniformity of morphology and small particle size is the sample that Cu2ﰪ is 0.4 and is calcined at 600ºC. With rising temperature and using surfactant, the aggregation reduces and crystallinity improves but the size of nanoparticles becomes large.