Commercial HZSM-5 (Si/Al=80) was calcined in air at 500 °C for 4 h before use to remove adsorbed water, noted as Z5. The HZSM-5@2SiO2 catalyst was prepared as follows: 4.0 g of calcined HZSM-5 catalyst powder was immersed in a mixture of 5.0 ml TEOS and 2.0 ml cyclohexane for 4 h. Then, it was dried overnight in a blast oven at 110 °C. Finally, the dried sample was calcined in an air muffle furnace at 550 °C for 4 hours. The above steps were then repeated one time and the resulting catalyst was recorded as Z5@2SiO2.