Formation of mesopores in zeolite beta by steaming: a secondary pore channel system in the (001) plane

The texture of a series of dealuminated macrocrystalline beta zeolites has been investigated by N(2) physisorption, transmission electron microscopy, and electron diffraction. Hydrothermal dealumination creates a secondary mesoporous system in zeolite BEA. N(2) physisorption together with DFT calculations indicated the presence of pores with an estimated size of 2-4 nm after steaming. After subsequent leaching, TEM revealed the newly formed cylindrical mesopores. As determined by electron diffraction, the new porous network consists of pores lying in the (0 0 1) plane. (C) 2003 Elsevier Inc. All rights reserved.