Coated composites of Al2O3—CeO2/ZrO2 and a method for their production

A method of producing a coated Al/Ce/Zr composite, the method comprising the steps of:

• i) preparing a non-calcined Al/Ce/Zr core, the non-calcined core being characterized by an alumina precursor of boehmite crystal structure having a crystallite size measured at the (020) reflection between 4 and 40 nm and a D-value of the (020) reflection of below 6.5 Å;
• ii) calcining the non-calcined Al/Ce/Zr core to form a calcined Al/Ce/Zr core;
• the calcined Al/Ce/Zr core consisting of two phases, an La stabilized Al2O3 phase and a Ce/Zr/Re2O3 mixed oxide phase, both phases forming a homogeneous mixture, the calcined Al/Ce/Zr core being further characterized by having a pore volume above 0.2 ml/g, and a maximum of the pore size distribution between 50 and 200 Å;
• iii) impregnating the calcined Al/Ce/Zr core with a metal oxide precursor such that the metal oxide precursor forms a coating on the core to form an impregnated core;
• and
• iv) calcining the impregnated core such that a metal oxide coating is applied to the core to form the coated Al/Ce/Zr composite, wherein the metal oxide coating forms between 1 to 50 wt. % after calcination of the coated Al/Ce/Zr composite.