Bimetallic Ni-Co/Al2O3 Catalysts Derived from Aluminate Spinels for Dry Reforming of Methane

Abstract

Five Ni-Co/Al₂O₃ catalysts for dry reforming of methane were obtained by high-temperature reduction of mixed Ni-Co spinel aluminates (Ni_xCo_1-xAl₂O₄) synthesised by a precipitation route. The aim of the study was to determine the effect of the incorporation of cobalt to the nickel aluminate spinel to the activity and selectivity of the resulting catalysts. The results indicated that the addition of cobalt was generally detrimental for the textural and structural properties of the mixed catalysts with respect to the monometallic nickel counterpart, thus producing catalysts with lower metallic dispersion. However, the presence of cobalt in the reduced catalysts resulted in an enhanced selectivity towards H₂ generation. In addition to that, the lower Ni content of the mixed catalysts resulted in an improvement in stability. As a result, the Ni_0.5Co_0.5Al₂O₄ mixed spinel was able to produce a Ni-Co/Al₂O₃ catalyst that exhibited higher reactant conversions, H₂/CO molar ratio of the product stream and higher stability than the Ni/Al₂O₃ monometallic catalyst.