Highly selective and stable bimetallic catalysts supported on different materials for n-butane dehydrogenation

Abstract

A study about the performance of Pt(0.3 wt%)Sn(0.3 wt%) catalysts supported on different materials in n-butane dehydrogenation is reported in this paper. The materials used as supports were γ-Al 2O 3, ZnAl 2O 4 spinel, MgAl 2O 4 spinel and spheres of α-Al 2O 3 with a washcoating of γ-Al 2O 3. The syntheses of both spinels leaded to very pure ZnAl 2O 4 and MgAl 2O 4 supports. The material prepared by washcoating showed the presence of an uniform and homogeneous layer of γ-Al 2O 3 (with a thickness between 12 and 18 μm) deposited on the spheres of α-Al 2O 3. The best behavior in activity, selectivity and stability through five severe cycles was achieved by bimetallic PtSn catalysts supported on MgAl 2O 4 spinel and on the material prepared by washcoating. The very good performance of these catalysts through the different cycles of reaction-regeneration can be due to the presence of metallic phases which preserve the strong intermetallic interaction along the different treatments, thus avoiding segregation processes.