Synthesis of barium hexaferrite and catalytic behavior in the combustion of methane

Barium hexaferrite doped with iridium was synthesized by two methods: the citrate gel and the polyacrylamide gel methods. The nature of phases obtained and the specific surface area were determined after heat treatments in air at 700 degrees C, 900 degrees C and in air containing 10% humidity at 1200 degrees C. The catalytic activity in the combustion of methane was measured after heat treatment at 900 degrees C. These hexaferrites showed a good catalytic activity after treatment at 900 degrees C. However this catalytic activity and the specific surface disappeared after heat treatment at 1200 degrees C.