Doping trace cerium in ZSM-48 in situ during hydrothermal synthesis for efficient hydroisomerization of a long-chain n-alkane

Abstract

Preparation of robust catalysts with high isomer yield still poses challenges for efficient hydroisomerization of long-chain n-alkanes. ZSM-48 is a competitive candidate for a support due to its unique one-dimensional pore structure. However, its excessive acidic sites lead to serious cracking side reactions. Herein, a facile one-pot in situ method of trace cerium doping in ZSM-48 is developed, and the acidity property and structure of ZSM-48 are finely tuned by changing the Ce content. Compared with traditional ZSM-48, Ce-doped ZSM-48 has smaller specific surface area and microporous volume, and the concentration of strong Brønsted acid sites is effectively adjusted. Pearson correlation coefficients between the properties of ZSM-48 zeolite regulated by different amounts of Ce and the catalytic hydroisomerization performance of Pt/ZSM-48 are calculated, which demonstrate that strong Brønsted acid sites of ZSM-48 are significantly correlated with n-hexadecane isomerization yield. ZSM-48 doped with 0.41 wt% Ce with appropriate concentration of Brønsted acid sites shows superior hydroisomerization performance, reaching an iso-hexadecane yield of 87.0%.