Pt/ZSM‐22 with Partially Filled Micropore Channels as Excellent Shape‐Selective Hydroisomerization Catalyst

Abstract

AbstractPt/ZSM‐22 with partially filled micropore channels (Pt/Z22‐PF) was prepared through a facile in‐situ coke deposition approach. Compared with conventional Pt/ZSM‐22 with evacuated micropore channels (Pt/Z22‐E), Pt/Z22‐PF exhibits much higher activity and isomer yield in n‐dodecane hydroisomerization. Specifically, the turnover frequency of n‐dodecane and the maximum multibranched isomer yield on Pt/Z22‐PF are about twice that on Pt/Z22‐E (314 vs. 144 h−1, 49 % vs. 29 %). Theoretical simulations and adsorption experiments demonstrate that the diffusion limitation of hydrocarbon and the accessibility of acid sites inside the micropore channels are reduced dramatically because of the partial fill. This is beneficial for the diffusion of alkene intermediates and the suppression of cracking reactions, resulting in a superior activity and high yield of isomers, especially multibranched isomers.