Tailoring the physicochemical properties of zeolite catalysts

Abstract

Here we summarize our recent findings in the area of zeolite synthesis, focusing on pathways to control crystallization in the absence of organics, tailoring crystal habit with growth modifiers, and pioneering techniques in zeolite surface science to elucidate the mechanisms of growth.

Glycerol dehydration catalyzed by MWW zeolites and the changes in the catalyst deactivation caused by porosity modification

“…Nevertheless, a microporous framework is unfavorable because it hinders the access of bulky molecules, and the diffusion and mass transport of reactants and products are restricted [8][9][10]. Furthermore, the deposition of coke readily blocks the micropores, so that the internal acid sites become inaccessible and useless.…”

CO2 hydrogenation using bifunctional catalysts based on K-promoted iron oxide and zeolite: influence of the zeolite structure and crystal size

“…It is well-known that controlling the textural properties of the zeolites and, in particular, reducing their crystal sizes to the nanometer scale (below 100 nm), can have a remarkable influence, not only on the catalytic activity of the zeolitic catalyst in terms of catalyst deactivation, but also on the product selectivities, which can be substantially altered. [28][29][30] Indeed, recently we have shown how the ability to decrease the particle size of well-known industrial zeolite-based catalysts, such as Beta or MFI, to particle sizes between 10-20 nm, has a direct impact on the product selectivity in complex reaction systems, such as the oligomerization of light olefins to liquid fuels, where enhancing the molecular diffusion of the bulky products is critical to control the final product selectivities, 31 or the methanol-to-olefin process, where activity was eight-fold higher and selectivity to ethylene and propylene was significantly increased. 32 Herein, we propose the study of bifunctional tandem catalysts based on K-promoted iron oxide (K/Fe3O4) combined with three different zeolite structures, BEA, MFI and CHA, for the CO2 hydrogenation reaction at 320C and 25 bar.…”

Microfluidics and catalyst particles

“…However, very few studies have tried to implement their synthesis in microfluidics. Indeed, depending on the type of zeolite, the synthesis conditions can vary from room temperature to high temperatures (typically 200°C for the reaction and more for the calcination step 104 ). In zeolite synthesis precise control of the synthesis conditions is important, because there are many different types of zeolites in terms of their structure.…”