A nanophase oxygen storage material: Alumina-coated metal-based ceria

摘要

Nanoparticles of Ce_(1-x) M_xO_(2-delta) (M = Ca or Zr) coated with A1_2O_3 with average crystallite size of 10 nm have been synthesised via solution chemistry approach under controlled chemical and hydrodynamic conditions. Their synthesis has been accomplished in three major steps: (1) simultaneous co-precipitation of cations, (2) sequential precipitation of A1(OH_3 over the former particles and (3) calcination of the precipitated precursors to the corresponding oxides. Several compositions have been synthesised and their physicochemical properties are compared with commercial state-of-the-art material. The Al_2O_3-coating hinders the particles growth at high temperatures, resulting in materials with a large specific surface area and a restrain in the decrease of their oxygen storage capacity.