Downsizing the K-CHA zeolite by a postmilling-recrystallization method for enhanced base-catalytic performance

摘要

Herein, we report the preparation of potassium chabazite (K-CHA) zeolite nanocrystals with enhanced base-catalytic performance using a bead-milling and postmilling-recrystaization technique. Particles as small as 60 nm were produced by this approach. The surface area of the downsized K-CHA samples showed a significant improvement, increasing from 11 m(2) g(-1) to 65 m(2) g(-1). The catalytic activity of the K-CHA nanocrystals in the Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate was found to be twofold higher than that of the raw and the milled samples, achieving 80% product yield within a reaction time of 60 min. In addition, the enhanced cataIytic behavior of the K-CHA nanocrystal, despite possessing Low surface area relative to the intermediate milled sample, is attributable to the postmilling-recrystallization step, which played a pivotal role in restoring the crystallinity to around 80%.