Carbon templated SAPO-34 with improved adsorption kinetics and catalytic performance in the MTO-reaction

Transport pores were introduced into a crystalline silicoalumophosphate (SAPO-34) using carbon materials as hard templates. Carbon nanoparticles and carbon nanotubes were added as secondary templates during the hydrothermal synthesis. By using a mixed template (morpholine and TEAOH) in the SAPO-34 synthesis it was possible to maintain the crystallinity, the surface area and decrease the formation of amorphous phase. The obtained materials were characterized with XRD, SEM, NMR, NH3-TPD, EDX and N2-physisorption measurements. n-Butane uptake experiments as well as catalytic test revealed that the type of carbon material is important for the accessibility of the hierarchical pore system. The mesopores created by carbon nanoparticles are located inside the particle but do not form a three-dimensional mesopore network. A significant improvement in the kinetic uptake of n-butane and in the conversion of methanol could be observed for the carbon nanotube-templated materials, containing mesopores accessible from the outside of the particle. Reactivation experiments revealed transport pores to be stable even after several regeneration cycles.

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► Carbon-templated SAPO-34 zeolite.
► Improved catalytic lifetime in the methanol conversion with carbon nanotube-templated SAPO-34.
► Faster uptake of n-butane due to hierarchical pore system.