The effect of zinc content on n-pentane isomerisation over Zn-S2O82-/ZrO2-Al2O3 catalyst

A number of Zn-S2O82-/ZrO2-AL(2)O(3) (Zn(x)-SZA) catalysts with different Zn mass fractions were synthesised and characterised by using X-ray diffraction, the Brunauer-Emmett-Teller method, and H-2 temperature-programmed reduction. The structure and isomerisation performance of Zn(x)-SZA catalysts were studied using n-pentane as a probe reaction. The results showed that a pure tetragonal ZrO2 phase was formed on Zn(x)-SZA, and the ZrO2 crystallite sizes of the tetragonal phase increased in the order: Zn(0.5)-SZA < Zn(1.0)-SZA < Zn(1.5)-SZA < Zn(2.0)-SZA < SZA. Zn can strengthen the interaction between persulfate ions and the support, promote the formation of stronger acidity, lead to a better dispersion of sulfate ions on the surface, and improve the redox performance of the catalysts. The Zn(1.0)SZA catalyst exhibited the best catalytic activity for n-pentane isomerisation. At a temperature of 170 degrees C, a reaction pressure of 2.0 MPa, a molar H2/n-pentane ratio of 4:1, and a weight hourly space velocity of 1.0 h(-1), the isopentane yield reached 58.0%.