Effect of support in Ni-Bi-O/support catalyst on oxidative dehydrogenation of n-butane to butadiene

Abstract

NiO-Bi2O3/different support catalysts, 20wt% Ni and 30wt% Bi as metal weight to support weight (hereafter 20wt%Ni-30wt%Bi-O/support) have been studied for oxidative dehydrogenation of n-butane to butadiene. Al2O3, SiO2, ZrO2 and none (: without support) were served as gel and sol type supports. As the results, activity and selectivity of oxidative dehydrogenation of n-butane to butadiene over the Ni-Bi-O/support catalyst strongly depended on the supports. The order of the butadiene selectivity as gel-type support was Al2O3>SiO2>ZrO2≫none, while SiO2 showed the highest butadiene selectivity from 1-butene feedstock. The gel-type support effect as a hierarchical nano-particle cohabitation was also studied by using equilibrium adsorption method for the Ni-Bi-O impregnation. In the sol-type support case, the order is SiO2>Al2O3>ZrO2, where the SiO2 sol shows not only superior to gel-type but also the best performance (n-butane conversion: 35.6%, selectivity: dehydrogenation 78.3%, butadiene 41.6%) among support types and species. The sol-type SiO2 hold balanced acid and base sites cooperating to improve butadiene selectivity, with oxygenate suppressed by accelerating redox system with non-hierarchical nano-particle cohabitation of NiO, Bi6O7 and support SiO2.