Effects of the partial replacement of La by M (M=Ce, Ca and Sr) in La(2-x)M(x)CuO(4) perovskites on catalysis of the water-gas shift reaction

Abstract

The performance of La(2-x)M(x)CuO(4) perovskites (where M = Ce, Ca or Sr) as catalysts for the water-gas shift reaction was investigated at 290 degrees C and 360 degrees C. The catalysts were characterized by EDS, XRD, N(2) adsorption-desorption, XPS and XANES. The XRD results showed that all the perovskites exhibited a single phase (the presence of perovskite structure), suggesting the incorporation of metals in the perovskite structure. The XPS and XANES results showed the presence of Cu(2+) on the surface. The perovskites that exhibited the best catalytic performance were La(2-x)Ce(x)CuO(4) perovslcites, with CO conversions of 85%-90%. Moreover, these perovskites have higher surface areas and larger amounts of Cu on the surface. And Ce has a higher filled energy level than the other metals, increasing the energy of the valence band of Ce and providing more electrons for the reaction. Besides, the La(1.80)Ca(0.20)CuO(4) perovskite showed a good catalytic performance.