Engineering low-temperature ozone activation of zeolites: process specifics, possible mechanisms and hybrid activation methods

Zeolite activation is the first, but often overlooked, post-synthetic treatment needed to transform an as-made material into an adsorbent or catalyst. Ozonation at low temperatures provides an alternative for conventional calcination treatments, with important consequences for zeolite stability and acidity. While sometimes used in the context of emptying novel less thermally stable structures, a thorough look at ozonation for bulk zeolites is missing. Decomposition of organic structure-directing agents was achieved for three OSDA-zeolite systems yielding empty SSZ-13, ZSM-5 and β zeolites at select ozonation conditions. The effect of various process parameters, as well as synthetic parameters, were investigated. Infrared and mass spectrometry after alternating O2-O3 activation mode experiments provide some mechanistic insights into ozonation. The rate-limiting steps of both low-temperature ozonation and air calcinations can be circumvented by low-temperature ozonation after medium-temperature calcination.

Jaar van publicatie:2021

Toegankelijkheid:Open