Cerium-zirconium-aluminum-based composite material, cGPF catalyst and preparation method therefor
A cerium-zirconium-aluminum-based composite material, a cGPF catalyst and a preparation method thereof are provided. The cerium-zirconium-aluminum-based composite material adopts a stepwise precipitation method, firstly preparing an aluminum-based pre-treated material, then coprecipitating the aluminum-based pre-treated material with zirconium and cerium sol, and finally roasting at high temperature to obtain the cerium-zirconium-aluminum-based composite material. The cerium-zirconium-aluminum-based composite material has better compactness and higher density, and when it is used in cGPF catalyst, it occupies a smaller volume of pores on the catalyst carrier, such that cGPF catalyst has lower back pressure and better ash accumulation resistance, which is beneficial to large-scale application of cGPF catalyst.
1. A method of preparing a cerium-zirconium-aluminum-based composite material, which comprises the following steps:
(1) Dissolving pseudo-boehmite in citric acid aqueous solution, adjusting the pH value to 4-10 with ammonia water, filtering and drying after the reaction under stirring is completed to obtain a precipitate; roasting the precipitate at a temperature of 200-400° C. for 0.1-5 h to obtain a pre-treated material; wherein the mass ratio of pseudo-boehmite to citric acid is 5-20:1;
(2) Adding the pre-treated material into a solution of mixed sol, adjusting the pH value to 4-10 with ammonia water after completely dissolution, filtering and drying after the reaction under stirring is completed to obtain a mixture precipitate; wherein the mixed sol is a sol containing cerium ions and zirconium ions;
(3) Roasting the mixture precipitate at 500-600° C. for 1-10 h, and then at 800-1100° C. for 1-10 h to obtain the cerium-zirconium-aluminum composite material.
2. The method according to claim 1 , wherein the mixed sol in step (2) is a sol which further contains one or more selected from the group consisting of yttrium ion, lanthanum ion, neodymium ion, praseodymium ion, palladium ion and strontium ion.