Investigation of mesoporous NiAl2O4/MOx (M = La, Ce, Ca, Mg)–γ-Al2O3 nanocomposites for dry reforming of methane

Abstract

One-pot synthesized mesoporous NiAl₂O₄/γ-Al₂O₃ and NiAl₂O₄/MO_x (M = La, Ce, Ca, Mg)–γ-Al₂O₃ nanocomposites with excellent textural properties were employed for the dry reforming of methane (DRM). NiAl₂O₄/La₂O₃/γ-Al₂O₃-imp prepared via a traditional impregnation method was used for comparison. The promotion effect of modifiers on the physicochemical properties and catalytic performance of the catalysts was systematically investigated. Characterization and evaluation results indicated that the modified catalysts showed higher activities and better coking-resistance than Ni/γ-Al₂O₃, and Ni/La₂O₃–γ-Al₂O₃ was found to be the most effective one. All the catalysts with or without modifiers presented similar Ni particle sizes due to the enhanced metal–support interaction derived from the reduction of the NiAl₂O₄ precursor. However, more medium-strength basic sites on the catalyst surface were obtained by adding promoters, which could facilitate the adsorption/activation of CO₂ and the gasification of amorphous carbon, improving the catalytic properties and accelerating the coke elimination rate. Additionally, the incorporation of promoters also prevented the phase transformation of γ-alumina.