Template synthesis and characterization of mesoporous γ-Al ₂O₃ hollow nanorods using Stevia rebaudiana leaf aqueous extract

Mesoporous γ-Al₂O₃ hollow nanorods have been synthesized using aluminum isopropoxide as Al source and Stevia rebaudiana leaf extract (a complex mixture of eight sweet diterpene glycosides including stevioside, rebaudioside A, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside E, dulcoside and steviol bioside) as template to direct the formation of mesoporous alumina on the aqueous system. Several characterization techniques were used, including XRD, TGA, N₂ physical adsorption, FE-SEM, TEM, and FT-IR. By drying the mixture at 80 °C and then calcining it at 650 °C, a material with high surface area (357 m²/g) and uniform pore sizes was obtained. The diameter and the length of the synthesized hollow nanorods ranged from 13 to 25 nm and from 40 to 50 nm respectively.