Effect of Extra-Framework Fe Species in Pt/Fe/ZSM-23 Catalysts on Hydroisomerization Performance of n-Hexadecane

Pt/xFe/ZSM-23 catalysts with various Fe contents were prepared to explore the influence of extra-framework Fe (EFFe) on the n-hexadecane (n-C-16) hydroisomerization performance. UV-vis and Fe-57 Mossbauer spectroscopic results suggest that the Fe species composition was significantly different under various Fe contents, with (HO-Fe(III)-O-Fe(III)-OH) and [Fe(OH)(2)](+) as the main Fe species at low Fe content (<1.98 wt %), whereas the Fe2O3 clusters/particles as the dominant ones at high Fe content (>1.98 wt %). Moreover, the concentration of Bronsted acid sites and Pt dispersion could be controlled by tailoring the Fe content. Correspondingly, the hydroisomerization performance of n-C-16 over Pt/xFe/ZSM-23 catalysts was dramatically changed with various Fe contents. The Pt/1.98Fe/ZSM-23 catalyst with 1.98 wt % EF-Fe content exhibited considerably excellent hydroisomerization performance, and both n-C(16 )conversion and selectivity to iso-hexadecane (i-C-16) could reach over 80 wt % when the reaction temperature was 310 degrees C.

Automated summary

The performance of Pt/xFe/ZSM-23 catalysts can be controlled by adjusting the extra-framework Fe content, with the catalyst exhibiting excellent hydroisomerization performance when the Fe content is 1.98wt%. The conversion of n-C(16) and selectivity to i-C-16 can both reach over 80wt% at a reaction temperature of 310 degrees Celsius.