Comparative study of nano copper aluminate spinel prepared by sol-gel and modified sol-gel techniques: Structural, electrical, optical and catalytic studies

摘要

The effect of ethylenediamine addition in the sol-gel method for the preparation of nano CuAl_2O_4 spinel for the enhancement in their structural, electrical, optical and catalytic properties was investigated. The samples were prepared by two different methods: sol-gel and modified sol-gel technique using ethylene-diamine. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms, temperature dependent conductance measurements, thermoelectric power (TEP) measurements and UV-visible diffuse reflectance (UV-vis-DRS) spectra were used to characterize the samples prepared. CuAl_2O_4 prepared by modified sol-gel technique was found to possess a higher surface area, lower crystallite size, lower activation energy and high porosity than the one prepared by sol-gel method which in turn lead to the improved performance of it towards the selective oxidation of benzyl alcohol to benzaldehyde. Effect of solvent on the catalytic oxidation of benzyl alcohol by the nano CuAl_2O_4 prepared by modified sol-gel technique was also investigated.