Effect of Molar Ratio and Calcination Temperature on Particle Size of CeO2/γ-Al2O3 Nanocomposites Prepared via Reverse Micelle Process

A porous composite of cerium oxide and gama aluminum oxide pigments were prepared via solgel processing controlled within reverse micelles of nonionic surfactant Triton X114 in cyclohexane. The precursor in heated at several calcinations temperature between 823 to 1123K. This process includes three steps. In the first step of preparation the ceria sol was prepared. In the second step, cyclohexane was mixed with surfactant and distilled water by the addition of ceria sol. In final step, nano gama aluminum oxide was fluently injected into the mixture. The precursor micellar ceria/γ-alumina sol with different molar ratio was mechanically stirred to form a homogeneous suspension. The mixture was washed with some organic solvent. Also, the effect of different molar ratio of Ce:Al on the crystallization was studied. The study of Xray diffraction XRD, transmission electron microscopy TEM, scanning electron microscopy SEM, temperature programmed reduction TPR and N2 adsorption/desorption isotherm suggested that well crystalline nanosized pigments are obtained. The product pigments posses mesoporosity with broadly distributed pores between 20 to 45 nm diameters. Surface area increases by increasing the calcination temperature. Also, the particle size of the pigments decreases with increasing the Ce:Al molar ratio.