Co-Templating Role of EDA and PEG in Synthesis of Mesoporous Alumina

Nano-scale mesoporous alumina powder (gamma-Al2O3) was synthesized by a precipitation-ultrasonic treatment-calcination method using aluminum nitrate and ammonia solution as raw materials and ethyl diamine (EDA)/polyethyleneglycol (PEG) as co-template agents. The samples were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), N-2 adsorption-desorption and acid-base titration methods. The results showed that the samples can be transformed into nano-sized mesoporous gamma-Al2O3 with needle or rodlike morphology, centralized pore size distribution and stable structure. The average pore size, pore volume and specific surface area of the obtained sample were 5.8 nm, 1.13 cm(3).g(-1) and 510 m(2).g(-1) respectively. A co-templating mechanism of EDA and PEG in the synthesis of mesoporous alumina was discussed based on the chemical reactions and speciation of EDA and alumina surfaces as a function of pH in aqueous solution.