Catalytic Influence of Bimetallic Bifunctional Ni-Pd/H-β and H-Mordenite Nanoporous Catalysts for Hydroisomerisation of n-Octane

Abstract

Zeolite-β and mordenite were impregnated with 0.1 wt% Pd and varying the amount (0.1–0.5 wt%) of Ni. The prepared nanoporous catalyst were characterized by various physico-chemical techniques such as XRD, nitrogen adsorption–desorption isotherm (BET), NH3-TPD and TPR, XPS and TEM. Hydroisomerisation of n-octane was carried out in the temperature range from 200 to 450 °C in the presence of flowing H2 gas under 1 atm. Finally we found that Ni addition up to 0.3 and 0.2 wt% over 0.1 wt% Pd/H-β and H-mordenite enhances the n-octane conversion and isomerisation selectivity. As the Ni amount exceeds the threshold values, the conversion decreases with increase in cracked products, and also, the selectivity of mono and dibranched isomers were improved suggestion operation of PCP intermediate mechanism. The bimetallic catalysts were more selective to the formation of dibranched isomers with higher octane number, when compared with monometallic catalysts. Ni-Pd loaded zeolite-β supports always show higher activity and selectivity than mordenite supports. Moreover, we achieved higher conversion (74.9 %) and isomerisation selectivity (92.5 %) at low Ni loading (0.3 Ni wt% over 0.1 Pd wt%/Hβ) for the first time.