Methanation of CO2 over nickel-lanthanide bimetallic oxides supported on silica

Abstract

The synthesis of Ni-Ln bimetallic oxides (Ln = La, Ce, Pr, Sm, Dy, and Yb; Ni/Ln = 5) supported on silica and their study as catalysts for the methanation of CO2 was for the first time undertaken. Silica was obtained by electrospinning and the supported catalysts prepared by the incipient wetness impregnation technique with the Ni-Ln bimetallic oxides were equally distributed on the silica surface. The addition of lanthanides increases the catalysts activity and such increment was associated with the existence of a synergism between nickel and the 4f block element (doping effect of the lanthanides) that influence their basicity, decreases the catalysts particle size and increases its stability on the gaseous stream. The best results were those obtained over nickel–praseodymium and nickel–cerium bimetallic oxides that presents an activity per active site (Ni) 4–10 times higher than that measured over two reference catalysts, NiO/CeO2 and 5 wt% Rh/Al2O3, respectively, tested in the same conditions. This is a remarkable result and this work shows that supported nickel - lanthanide bimetallic oxides could be a real alternative to noble metal catalysts for the methanation of CO2.