A green chemical approach for synthesis of sponge-like mesoporous gamma alumina and evaluation of three parameters OH/Al, salt concentration and ageing time on BET and BJH properties

Abstract

Synthetic strategies to control the properties of gamma-alumina mesoporous have been discussed. In this study, the emphasis is placed upon the effect of three parameters pH of the reaction, salt precursor concentration and ageing time on the pore structure of nanoparticles synthesized by precipitation method. The gamma alumina as the only phase was recognized due to the appearance of characteristic peaks based on standard data JCPDS 29-0063 card in XRD pattern. The samples were analyzed by BET and BJH analysis in terms of specific surface area and pore structure (size distribution, morphology, and total pore volume). The results showed that all the synthesized samples are mesoporous. The sample synthesized at a precursor concentration of 0.1 M and pH 8 and the ageing time of 48 h obtained the highest specific surface area (217.02 m2 g−1) among all samples, while the sample prepared at the precursor concentration 0.2 M and pH 8 showed the highest pore volume with a value of 0.31 cm3 g−1. Among the parameters, only pH altered the pore morphologies from spherical to cylindrical while the ageing time and salt concentration did not change the pore morphology of mesoporous alumina samples. The TEM image reveals the sponge-like morphology which implies the appearance of a highly inter-connected pore system.