Gallium-promoted mesoporous sulfated zirconia: A catalyst for n-butane isomerization

Mesoporous sulfated zirconia (m-ZrO2) were synthesized hydrothermally using Zr(O-nPr)4 as Zirconium precursor, ammonium sulfate as sulfur source and CTABr as template. Then the as-synthesized mesoporous zirconia were impregnated with gallium nitrate to give the Ga-promoted mesoporous sulfated zirconia.(m-GSZ). The catalysts were characterized by nitrogen physisorption(BET) for texture properties; x-ray diffraction and TEM for structures. The catalytic conversion of n-butane isomerization was measured in a flow reactor. With the addition of a proper amount of Ga as a promoter, the catalytic activity of for n-butane isomerization at a very low temperature of 200 °C in flow system was strongly promoted, giving near-equilibrium production of iso-butane. The remarkable increase of activities was determined primarily by the amount of Ga addition and the temperature of calcination. The nature of the promotion was determined by EPR for the oxidative de-hydrogenation activity of Ga2O3. Finally, we compare the activity of Ga-promoted SZ catalyst with the Al-promoted catalyst.