Catalytic performance of Cu‐Ni /La _{0. 75} Sr _{0 . 25} Cr _{0 . 5} Mn _{0 . 5} O _{3 ‐δ} for dry methane reforming

Abstract

La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) powders with perovskite structures were prepared by the glycine-nitrate process (GNP), and Cu-Ni/LSCM catalyst with Ni and Cu atomic mass ratios of 3:1, 4:1, 5:1, and 6:1 was prepared by impregnation. The structures and properties of the samples were characterized and the Cu/Ni-LSCM catalysts were subjected to dry methane reforming at 600°C/700°C. X-ray diffraction (XRD) patterns showed that the samples contained perovskite structure and Cu-Ni alloy phases. Hydrogen-based temperature-programmed reduction (H2-TPR) showed that the reduction temperature of CuO/NiO-LSCM decreased as the Cu content increased. X-ray photoelectron spectroscopy (XPS) results of Cu and Ni elements showed Cu-Ni alloy formed after reduction, and the extent of carbon deposition on the spent catalysts was measured using thermogravimetric analysis (TGA). The effect of wet impregnation on the structure and properties of Cu-Ni/LSCM composite anodes was investigated. The results showed that the four Cu-Ni/LSCM catalysts had slightly different methane conversions during dry methane reforming at 600/700°C. The conversion of methane increased first and then decreased as Ni/Cu mass ratio increased and the maximum was 88.75%. The best catalytic performance was obtained at sample 3(Cu:Ni = 1:5 in mass ratios) for its largest surface area, which was 10.797 m2/g and the highest Ni content.