Effect of Pd content on the catalytic performance of SO₄^2-/ZrO₂-WO₃ solid superacid in pentane isomerization

Pd-SO₄^2-/ZrO₂-WO₃ solid superacid catalysts were prepared and characterized by XRD, FT-IR, TPR, XPS, BET and TG-DTA; the effect of Pd content on its catalytic performance in n-pentane isomerization was investigated. The results showed that Pd can reduce the reduction temperature, increase the decomposition temperature of SO₄^2- and therefore improve the thermostability of the Pd-SO₄^2-/ZrO₂-WO₃ catalysts. Pd-SO₄^2-/ZrO₂-WO₃ with a Pd mass fraction of 0.05% exhibits the highest catalytic activity for isomerization; over it under 260℃, 2.0 MPa, mass hourly space velocity of 1.0 h^-1, and H₂/n-pentane molar ration of 4.0, the conversion of n-pentane and the yield of liquid products are 40.1% and 93.9%, respectively.