Preparation of gallium-promoted SO₄^2-/ZrO₂ and its catalytic performance for isomerization of n-butane

A series of gallium-promoted nanocrystalline sulfated zirconia (SO₄/^2-/Ga₂O₃/ZrO₂) were prepared by wetness impregnation of zirconium hydroxide with an aqueous solution of Ga₂(SO₄)₃. The structure and the acidity of SO₄/^2-/Ga₂O₃/ZrO₂ catalyst were characterized. The gallium-doped sulfated zirconia could prevent the grain growth and stabilize the tetragonal phase. The catalyst had a narrow size distribution and the average crystallite size was about 8 nm. The n-butane isomerization on the catalyst was studied in the presence of hydrogen. Compared with other metal-promoted catalysts, the catalytic activity and the stability of SO₄/^2-/Ga₂O₃/ZrO₂ were greatly improved. The n-butane conversion on the catalyst containing x(Ga₂O₃) = 3% calcined at 700°C was > 51%, which was closed to the equilibrium conversion of n-butane.