Synthesis, structure and catalytic properties of Fe-substituted barium hexaaluminates

摘要: A sol–gel method using Ba and Al isopropylates iron nitrate has been used to synthesise barium hexaaluminate partially substituted with iron. After calcination under oxygen at 1200°C the β-alumina structure was obtained. Formation of mixed BaFexAl12-xO19 phase occurred for x=1–4. XRD measurements showed a good crystallinity expansion unit cell parameters due presence larger Fe3+ ions substituting Al3+ ones in octahedral sites only. Mossbauer spectroscopy revealed that are present four different slightly distorted. Catalytic activity methane combustion an optimum obtained solid containing 2 Fe per cell: increase amount introduced counterbalanced by decrease specific surface area. Intrinsic activities have calculated solids both fresh aged states. It is observed increasing content increases relative same ratio as populations located two deduced from spectroscopy. then tentatively assumed attributed octahedrally coordinated some sites.