Effect of Metal-Support Interactions in Ni/ZSM-5 + Al2O3 Catalysts on the Transformation of n-Paraffins

Abstract

NiO(8 %)/Ni,H-ZSM-5 + Al2O3 (1:1) catalysts differing in metal-support interactions, which influenced the metal-to-acid ratios, were examined. The interactions were changed by modifying the method of zeolite and aluminium hydroxide combining and the method of Ni incorporation. The catalysts were characterised by ICP, XRD, N2 sorption, SEM, TEM, NH3-TPD, Py-IR, TPR, H2 chemisorption and XPS. The effect of metal-support interactions was determined during n-C6 conversion in a continuous system at H2:CH = 7:1 Nm3/m3, 0.1 MPa and LHSV = 1 h−1. It was found that over the catalysts with weaker Ni–alumina interactions (n Ni_a/n, 3.2 × 10−2 and 4.8 × 10−2), selectivity to isomerisation products was by 10–35 % higher, and selectivity to high boiling hydrocarbons by 10–30 % lower than over the catalysts with stronger Ni-support interactions (n Ni_a/n, 1.2 × 10−2 and 1.8 × 10−2).