Boosting the growth kinetics of extra-large pore zeolite ZEO-1

Abstract

The first stable aluminosilicate zeolite with extra-large pores, ZEO-1, marks the great breakthrough in zeolite community after decades of exploration and endeavors, opening possibilities for processing bulky substrates. However, the long synthesis cycle and relatively low reproducibility hinders the wide application of this intriguing material. Here, we report the synthesis of ZEO-1 zeolite using a tentatively so-called “deficient fluoride approach”, i.e., a small amount of fluoride sources was introduced to the gel rendering the stoichiometrically unbalanced charge of the cation and anion from the OSDA and fluoride sources. Using this approach, faster crystallization and higher reproducibility of ZEO-1 zeolite were achieved compared to the originally reported protocol. The physicochemical properties of the obtained products were analyzed using comprehensive characterizations, including PXRD, SEM, TEM, ICP-OES, TG, MAS NMR, FTIR, etc. The crystallization kinetics of ZEO-1 were performed by following up and characterizing the extracted products obtained at different temporal stages. The plausible role of fluoride in boosting the crystallization of ZEO-1 zeolite was discussed. The catalytic performance of alkylation of phenol with tert-butanol was evaluated and compared with other large and extra-large pore zeolites.