Hydroisomerization of n-Octane over Bifunctional Ni−Pd/HY Zeolite Catalysts

Abstract

Bifunctional catalysts containing 0.1−0.5 wt % nickel and 0.1 wt % palladium supported on HY zeolite were prepared through incipient wetness impregnation (IWI) and characterized by X-ray diffraction (XRD), Brunauer−Emmett−Teller (BET) surface area, temperature-programmed desorption of ammonia (NH3-TPD), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Hydroisomerization of n-octane was carried out between 200 and 450 °C under 1 atm of pressure, and it was found that Ni addition up to 0.3 wt % over 0.1 wt % Pd/HY zeolite enhanced the n-octane conversion and isomerization selectivity with a low percentage of cracked products. As the Ni amount exceeds the threshold values, the conversion decreases with an increase in cracked products, and also, the selectivity of mono- and dibranched isomers was improved, suggesting the operation of a protonated cyclopropane (PCP) intermediate mechanism. As a conclusion, the bimetallic catalysts were ...