Understanding the role of tetramethyl urea for the synthesis of mesoporous alumina

AbstractMesoporous alumina was synthesized by hydrothermal method at 150°C for 6–24h using tetramethyl urea followed by their calcination at 500–1100°C. The samples were characterized by XRD, FTIR, N2 adsorption–desorption, FESEM and TEM. The γ-Al2O3 was found to be stable up to 1000°C for the samples prepared at 150°C/6h, and up to 900°C for the samples prepared at 150°C/12–24h. The BET surface area values of 500°C treated samples were 428m2g−1, 393m2g−1, and 366m2g−1 for the reaction time of 6h, 12h and 24h, respectively. FESEM and TEM showed the formation of alumina nanoparticles at 150°C/6h, which ripened to flake-shaped alumina comprising of alumina nanoflakes (70–100nm) at 150°C/12–24h. To understand the role of tetramethyl urea, a tentative formation mechanism was illustrated