Cerium oxide-zirconium oxide based composite rare-earth oxide with high specific surface area and high oxygen storage capacity and preparation method thereof

Abstract

The invention discloses a method for preparing a cerium oxide-zirconium oxide based composite rare-earth oxide. The method comprises the following steps of: (1) heating a zirconium salt solution at room temperature, slowly adding sulfate ions, controlling the temperature rise rate so that the temperature is increased in the range of 90-95 DEG C when the sulfate ions are added completely, and then preserving heat for 20-100 minutes, thereby forming a zirconium basic sulfate composite salt precursor; (2) adding a cerium salt and a rare-earth metal salt to the precursor solution and stirring evenly, thereby obtaining a slurry; (3) settling the slurry by using basic carbonate and / or a basic oxalate solution, thereby obtaining a precipitate; and (4) filtering and washing the precipitate obtained in the step (3), removing purities, and calcining the washed precipitate. The cerium oxide-zirconium oxide based composite rare-earth oxide prepared by the method by controlling raw materials and process conditions has the characteristics of being high in total fine pore volume, high in fresh specific surface area, high in oxygen storage capacity and the like.

Description

technical field [0001] The invention relates to a ceria-zirconia-based composite rare earth oxide and a preparation method thereof, in particular to a ceria-zirconia-based composite rare-earth oxide with high specific surface area and high oxygen storage capacity and a preparation method thereof. Background technique [0002] Because the tail gas emissions of automobiles, motorcycles and tractors, especially motor vehicles such as automobiles, have become the main source of air pollution in large and medium-sized cities in the world, and the most effective measure to control motor vehicle exhaust emissions is to install off-board vehicle exhaust purifiers. As the activated carbon layer of the carrier of the automobile exhaust purifier, the cerium-composite material has become an indispensable material for the automobile catalyst. The cerium-composite material has good oxygen storage capacity and high-temperature hydrothermal stability, which can effectively widen the air-fue...

AI Technical Summary

Problems solved by technology

The cerium-zirconium catalyst prepared by the traditional method can maintain good oxygen storage performance at high temperature, which can meet the requirements of high-performance automobile exhaust purification three-way catalyst for oxygen storage performance and high-temperature stability of oxygen storage materials, but the cerium-zirconium solid solution can The thermal stability of the lower structure is poor, and the specific surface area is relatively small

As reported, after the prepared cerium-zirconium oxygen storage material is calcined at 1000°C for 4 hours, the oxygen storage capacity at 200°C can still reach more than 300 μmol / g, but the specific surface area is less than 10g / m 2

The three-way catalyst must have strong durability at high space velocity, and traditional cerium-zirconium materials dissociate tetragonal ZrO at higher temperatures 2 , so that the single cubic phase transforms into multi-phase coexistence, phase separation and instability of texture properties will lead to a serious decline in catalyst performance