The introduction of transition metal atoms into zeolites can significantly improve their catalytic performance. Herein, a series of Al free Fe-ZSM-23 zeolites were synthesized via hydrothermal synthesis. The samples were characterized by XRD, SEM, N-2-physical adsorption, UV/Vis, FTIR, XPS, ICP, NH3-TPD and Py-IR. In addition, the hydroisomerization of n-dodecane were conducted over the zeolites loading 0.5 wt% Pt. The effect of Fe in the zeolites on catalyst acidity and alkane isomerization was studied. The results showed that the introduction of Fe in the zeolite framework can increase the isomerization selectivity, while an extremely low Fe content resulted in a significant decrease in catalyst activity and isomerization selectivity. (C) 2019 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.