Partial oxidation of methane over bimetallic nickel–lanthanide oxides

Abstract

The study of partial oxidation of methane (POM) over bimetallic nickel–lanthanide oxides was undertaken. Binary intermetallic compounds of the type LnNi (Ln = Pr, Gd, Lu) were used as bimetallic nickel–lanthanide oxides precursors and the products (NiO·Pr 2NiO 4, 2NiO·Gd 2O 3 and 2NiO·Lu 2O 3) were characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy, Raman and temperature programmed reduction. The catalytic activity increases when gadolinium or lutetium replaces praseodymium and the selectivity of the bimetallic nickel–lanthanide oxides is clearly different from that of single metal oxides and/or mechanical mixtures. The existence of an unusual synergism effect between the two metal oxide phases (NiO and Ln 2O 3) that lead to higher conversions of methane and higher selectivities to hydrogen and carbon monoxide correlate also the catalysts stability to deactivation. The activity and selectivity of the gadolinium and lutetium compounds is, under the same conditions, equivalent to that of a platinum commercial catalyst, 5 wt% Pt/Al 2O 3, which stresses the good catalytic performance of this new type of compounds for the production of H 2 and CO (H 2/CO = 2).