Sub-zeolite of FER topology derived from an interlayer modification of PLS-3 lamellar precursor

A simple HCl-EtOH solution treatment has been conducted to modify the structure of Al-PLS-3, a kind of FER lamellar precursor with various Si/Al ratios (60-∞). With prolonging the treatment time from 15 min to 24 h at 443 K, the precursors underwent a variety of structural changes, including removal of occluded organic species, loss of layer stacking order and restoration of an ordered structure by interlayer pillaring. The post structural modification gave rise to a sub-zeolite of FER topology within a short time of 40 min, which possessed disordered stacking of FER sheets, named as ECNU-8. The physicochemical properties of ECNU-8 were characterized by means of various techniques and in comparison to those of conventional FER topology. Still composed of a collection of FER sheets but without an ordered stacking manner along (1 0 0) direction, the structure of ECNU-8 was constructed by a reorientation of interlayer hydrogen bond moieties caused by partial removal of interlayer organic structure directing agent. The ECNU-8 materials with different Al contents possessed external surface areas enlarged by 23.1-36.8% in comparison to corresponding three-dimensional FER zeolites. Containing the FER laminates and tetrahedral Al in framework, but mitigating the spatial restrictions in particular for the bulk molecule reactions, ECNU-8 proved to be a promising solid acid catalyst for processing larger substrates.