Diffusion in Zeolites – Impact on Catalysis

Metal–organic framework based mixed matrix membranes: a solution for highly efficient CO2capture?

“…Moreover, the pore network can be 1-, 2- or 3-dimensional with different pore sizes or connectivities in different directions leading to diffusion anisotropy. 64 …”

Assemblies of Mesoporous FAU‐Type Zeolite Nanosheets

“…[3,4] Compared to the allover microporous channels in conventional zeolite crystals, such hierarchical pore systems, with wide transport pores intersecting the micropore network like motorways linking a narrow road system, are already proven to reduce diffusion limitations for molecules within zeolitic catalysts. [5][6][7][8][9][10] While for high-silica zeolites, such as ZSM-5, several methods for incorporating additional transport pores were developed during the past few years, [3,4,11] such a substantial collection of approaches is not available for low-silica zeolites. Herein, we present the synthesis and characterization results of Faujasite (FAU)-type zeolite X (Si/Al < 1.5) grown as house-of-cards-like nanosheet assemblies with intracrystalline mesoporosity.…”

“…[11] Zeolite crystals with additional meso (or in few cases macro) [12] pores can be produced by different methods, [13] for example, desilication by an alkaline post-treatment [14,15] or by the use of hard [16,17] and soft [9,[18][19][20] templates during zeolite synthesis. However, all the methods are usually limited to a certain group of zeolites or just to a special zeolite type.…”

Performance Enhanced SAPO-34 Catalyst for Methanol to Olefins: Template Synthesis Using a CO2-Based Polyurea

“…This result is consistent with that observed from TEM characterization. The mesopores in the crystals can facilitate the diffusion and mass transportation [1,37,53] of molecules especially coke species in the conversion of methanol to olefins reactions, and then can effectively decrease the coke blocking rate and prolong the full methanol conversion lifespan of the catalysts. with mesopores and macropores extending along the entire crystals.…”