Diesel fuel reforming over catalysts derived from LaCo_(1-x)Ru_xO_3 perovskites with high Ru loading

摘要

Catalysts derived from LaCo_(1-x)Ru_xO_3 perovskite precursors with high Ru loading (x = 0.2 and 0.4) were studied in the oxidative reforming of diesel for hydrogen production. High partial substitution of Co by Ru in LaCoO_3 perovskite modifies its physicochemical characteristics. It was observed that the high degree of Co substitution in the perovskite changes the rhombohedral crystalline perovskite particles to particles with orthorhombic structure, lower size and higher specific surface area. These modifications affected the structure and morphology of the catalysts derived from the reduction of the perovskite precursors. Catalysts derived from LaCo_(1-x)Ru_xO_3 perovskite precursors with high Ru loading shown particles of La_2O_3 and Co0 with small particle size and high surface concentration of Ru° particles. The modifications in the structural characteristics of the catalysts induced by the addition of Ru in the LaCo_(1-x)Ru_xO_3 perovskite precursor had influence on their catalytic behaviour in the oxidative reforming of diesel. The catalyst derived from the perovskite with higher degree of Co substitution (x = 0.4) showed the higher activity and stability for the production of hydrogen for long periods of time-on-stream. The greater Ru exposition achieved in this catalyst was responsible of the increase in the stability observed in this sample taking into account the lower tendency to form carbonaceous deposits of the Ru particles formed.