Evaluation of some cobalt and nickel based perovskites prepared by freeze-drying as combustion catalysts

A series of cobalt and nickel based perovskite type catalysts with high specific surface area (8–20 m² /g) was prepared by spray-freezing/freeze-drying method. The catalytic activity of all samples in methane combustion was evaluated by measuring the light-off temperature, the conversion at 823 K and the temperature of the end of the reaction. The experimental data suggest higher activity than reported in literature for similar or other perovskites, and confirm its strong dependence on the specific surface area. Among eleven tested catalysts, including seven new compositions four of which showed excellent activity, La_0.66Sr_0.34Ni_0.3Co_0.7O₃ was the best performing.