Effects of different ion dopants on the structure and catalytic performance of lanthanum hexaaluminates in methane combustion

Lanthanum hexaaluminates doped with different metal ions (Fe, Co, Ni, Cu, and Mg) were prepared through co-precipitation of metal nitrates in the water phase of a Triton X-100 / n-hexanol / cyclohexane reverse microemulsion and used as the catalyst in methane combustion. Their structure and properties were characterized by X-ray powder diffraction (XRD), specific surface area (BET) and scanning electron microscope (SEM); the effects of ion dopants on their catalytic performance in methane combustion were investigated. The lanthanum hexaaluminates doped with Fe and Mn exhibit high catalytic activity and stability for methane combustion at high temperature; over the LaMnFeAl₁0O₁9-δ catalyst calcined at 1200℃, the ignition temperature (T₁0%) and complete combustion temperature (T₉0%) are 477℃ and 674℃, respectively.