N-Pentane isomerization over platinum-promoted W/Zr mixed oxides supported on mesoporous silica

W/Zr mixed oxides supported on various porous silica materials, namely SBA-15, MCM-41 and silica gel, were prepared. Their acidities and catalytic activities in n-pentane isomerization were examined. For the mesoporous silica, SBA-15 was found to retain the ordered meso-structure better than MCM-41 after loading with W/Zr mixed oxide. TEM photographs showed that tungstated zirconia was dispersed inside the mesoporous channels of SBA-15, and that the surface area and pore volume decreased with the loading. The SBA-15 supported WO ₃/ZrO₂ materials promoted with Pt were highly catalytic efficient in n-pentane isomerization with a very high iso-pentane selectivity. In contrast, MCM-41 and silica gel supported WO₃/ZrO₂ showed lower catalytic activities. The optimal activity was observed on SBA-15 with 1%Pt/20%WO₃/40%ZrO₂. The mesoporous silica supports played an important role in stabilizing the mixed oxide catalyst since the catalytic activity decayed less markedly with time-on-stream on the supported catalysts.