Direct Synthesis of Nano-Ferrierite along the 10-Ring-Channel Direction Boosts Their Catalytic Behavior

Abstract

Ferrierite zeolites with nanosized crystals and external surface areas higher than 250 m g have been prepared at relatively low synthesis temperature (120 °C) by means of the collaborative effect of two organic structure directing agents (OSDA). In this way, hierarchical porosity is achieved without the use of post-synthesis treatments that usually involve leaching of T atoms and solid loss. Adjusting the synthesis conditions it is possible to decrease the crystallite size in the directions of the 8- and 10-ring channels, [010] and [001] respectively, reducing their average pore length to 10–30 nm and increasing the number of pores accessible. The small crystal size of the nano-ferrierites results in an improved accessibility of reactants to the catalytic active centers and enhanced product diffusion, leading to higher conversion and selectivity with lower deactivation rates for the oligomerization of 1-pentene into longer-chain olefins.