Preparation and characterization of bimetallic Rh-Ni/Y2O3-Al2O3 for hydrogen production by raw bioethanol steam reforming: influence of the addition of nickel on the catalyst performances and stability

The influence of the addition of Ni on the catalytic behaviour of a Rh/Y2O3-Al2O3 catalyst (Rh/Y-Al) was evaluated in the ethanol steam reforming reaction in the presence of methyl-2-propan-1-ol as impurity. Physical-chemical properties of modified materials were determined by H2 chemisorption, XRD, BET, TPR, IR spectroscopy and TPO. It was established that the catalytic behaviour of the Rh/Y-Al base catalyst is widely improved by the addition of Ni. Nickel incorporation leads to the formation of both dispersed nickel phase and nickel aluminate species. Basic properties of the support were not modified by the addition of Ni but it was concluded to a rearrangement of acid sites. NiAl2O4 phase leads to an increase of the Lewis acid sites (LAS) of weak strength, generating a decrease of the production of coke and higher catalyst stability. It has been shown that the incorporation of Ni on the Rh/Y-Al catalyst increases the rhodium accessibility and stabilizes the rhodium particles size. Finally, the higher performances of RhNi/Y-Al catalyst were correlated to an increase in the methane steam reforming activity.