La 2−xCe xCu 1−yZn yO 4 perovskites for high temperature water-gas shift reaction

Abstract

The performance of La 2− x Ce x Cu 1− y Zn y O 4 perovskites as catalysts for the high temperature water-gas shift reaction (HT-WGSR) was investigated. The catalysts were characterized by EDS, XRD, BET surface area, TPR, and XANES. The results showed that all the perovskites exhibited the La 2CuO 4 orthorhombic structure, so the Pechini method is suitable for the preparation of pure perovskite. However, the La 1.90Ce 0.10CuO 4 perovskite alone, when calcined at 350/700 °C, also showed a (La 0.935Ce 0.065) 2CuO 4 perovskite with tetragonal structure, which produced a surface area higher than the other perovskites. The perovskites that exhibited the best catalytic performance were those calcined at 350/700 °C and, among these, La 1.90Ce 0.10CuO 4 was outstanding, probably because of the high surface area associated with the presence of the (La 0.935Ce 0.065) 2CuO 4 perovskite with tetragonal structure and orthorhombic La 2CuO 4 phase.