LAUSR

Abstract Al 2 O 3 beads with various pore sizes were successfully synthesized by combining ammonium alginate assisted sol-gel and emulsion template methods using liquid paraffin as pore-enlarging agent and polysorbate 80 as dispersant. The great influences of textural structure of Al 2 O 3 beads on the activity and stability of PtSn-La/Al 2 O 3 catalyst for isobutane dehydrogenation were investigated by N 2 adsorption-desorption, XRD, NH 3 -TPD, SEM, HRTEM, H 2 -TPR, XPS, isobutene transient response experiment and TG analysis. The results showed that Al 2 O 3 beads with tunable pore sizes (7.4–13.3 nm), surface areas (294-322 m 2 /g) and pore volumes (0.56–1.1cm 3 /g) could be obtained by changing the addition amount of liquid oil. Moreover, the transient response experiment stated that the PtSn-La/Al 2 O 3 catalysts with large pore sizes could enhance the diffusion speed of the gas molecule in the channels. With increasing the amount of liquid oil from 0 to 20%wt, the particle sizes of platinum decreased from 2.86 nm to 1.45 nm, the amount of carbon deposit declined by 30.6% and the final yield of isobutene increased from 42% to 48%. The enhancement of catalytic performance of PtSn-La/Al catalyst with larger pore size was related to its smaller Pt particles, lower surface acidity and diffusion resistance of reaction products in the pore.