From nano- to macro-engineering of ZSM-11 onto thin-felt stainless-steel-fiber: Steam-assisted crystallization synthesis and methanol-to-propylene performance

Abstract

• Thin-felt ZSM-11/SS-fiber is fabricated via a combined washcoating and SAC method. • Pre-aging treatment of the synthesis sol can facilitate the subsequent SAC growth. • The ZSM-11/SS-fiber catalyst shows the stability improvement for the MTP reaction. • The enhanced mass transfer by microstructured design is paramount for the stability improvement. Thin-felt ZSM-11/stainless-steel(SS)-fiber composites are successfully prepared via a combined washcoating and steam-assisted crystallization (SAC) method. Pre-aging of synthesis sol at a lower temperature of 80 °C can facilitate the zeolite nucleation and subsequent SAC growth at 180 °C. Such synthesis approach realizes the flexible tuning of acidity via adjusting SiO 2 /Al 2 O 3 molar ratio in a wide range, including but not limited from 105 to 425. The as-synthesized ZSM-11/SS-fiber composites are employed as catalysts for the methanol-to-propylene reaction, and the promising thin-felt catalyst with SiO 2 /Al 2 O 3 molar ratio of 200 shows remarkable stability improvement in comparison with its powdered counterpart, due to enhanced zeolite utilization efficiency and heat/mass transfer by the microfibrous-structured design.