Processing of mesoporous alumina from a powder precursor

Oxides with significant mesopore volume can be produced from gels through a mbient pressure drying (APD) if the oxide network within the gel is suffici ently strong, To obtain a strong alumina gel, a commercial alumina powder ( 100 nm diameter) was combined with different amounts of ethanol, water, and acid. Significant mesoporosity was observed in dried and calcined gels pre pared from this precursor and ethanol alone, particularly when "poor wettab ility" was established in the gel through azeotropic distillation in toluen e. When water (or water and nitric acid) was also utilized the pore volume decreased dramatically; this observation may be attributed to the creation of amorphous alumina from the crystalline precursor that is displaced into the interparticle pores, and in which mesopores are poorly preserved during APD.