Structural characterisation of lanthanum manganese perovskite catalysts by in-situ X-ray powder diffraction

摘要

Lanthanum manganese perovskites have a wide range of possible applications e.g. as heterogeneous catalysts. In this study the effect of an insertion of noble metals into the LaMnO_3 perovskite lattice was studied by in-situ X-ray powder diffraction. Citrate route prepared noble metal containing LaMnO_3 shows temperature-dependent expansion of the unit cell volume driven by the lattice parameters a and b and increases three fold in rate above 650°C. Cooling to room temperature affects the lattice parameters in the reverse manner compared to heating. This expansion and contraction of the unit cell is reversible for a minimum of three cycles.