A series of platinum/zirconium–hexagonal mesoporous silica (Pt/Zr-HMS) catalysts with different molar ratios of Si/Zr have been prepared and used for reforming reaction. The prepared catalysts were characterized by XRD, XRF, NH3-TPD, FTIR, Py-IR, nitrogen sorption, SEM, and TGA (for studying the coke deposition) techniques. The effects of various amounts of zirconium on the activity, selectivity, and coke deposition in the temperature range of 200–500 °C were compared. By increasing the incorporation of Zr into the Pt-HMS structure, the acidity of catalysts increased. The results show that the catalytic activity and selectivity for desired products (especially isomerization products) increased with decreasing Si/Zr amount (or increasing zirconium content). The best i-C7 selectivity (64.1%) was observed for Zr(5)-HMS at T = 200 °C.

The ammonia-SCR catalytic activity of unsupported CeVO 4 with an excess of CeO 2 was investigated in standard and fast-SCR conditions. Solids were obtained from a hydrothermal synthesis route under a mild condition and then stabilized after aging in a wet atmosphere at 600 and 850°C. Particular attention was paid to the role of excess CeO 2 and the consequences of hydrothermal aging on physicalchemical properties and catalytic activity. The XRD patterns put into evidence the formation of the zircon-type structure of CeVO 4 in agreement with a segregation of cubic face-centered structure of ceria (CeO 2 ). Along with adding an excess of CeO 2 , high specific surface area (102 m 2 /g) for the 11wt.% CeO 2 /CeVO 4 solid was obtained. The presence of CeO 2 nanoparticles in addition to CeVO 4 nanoparticles have limited the decrease in the specific surface area after aging at 600 and 850°C. The catalyst with 11wt.% CeO 2 /CeVO 4 exhibited the best catalytic performances in standard and fast SCR conditions after thermal aging at 600°C.