Cerium oxide and zirconium oxide based composite rare earth oxide with favorable ageing resistance and high reduction activity and preparation method of cerium oxide and zirconium oxide based composite rare earth oxide

Abstract

Provided is a method for preparing cerium oxide and zirconium oxide based composite rare earth oxide. The method comprises: (1) preparing a zircon salt solution; (2) prepare an activating agent solution by mixing urea and sulfuric acid or sulfate; (3) heating the zircon salt solution at a room temperature, dropwise adding the activating agent solution slowly, controlling the temperature rise speed to make the temperature raised to 60 degrees centigrade after the addition of the activating agent solution is finished, continuing to raising the temperature to 90 to 95 degrees centigrade, and keeping the temperature for 20-100min to form a basic zirconium sulfate composite salt precursor solution; (4) preparing soluble cerate and rare earth metal salt, adding the soluble cerate and the rare earth metal salt into the basic zirconium sulfate composite salt precursor solution, and performing precipitation by using a soluble hydroxide or ammonia solution; and (5) filtering and cleaning precipitates, and then, calcining the precipitates. Also provided is a cerium oxide and zirconium oxide based composite rare earth oxide prepared by using the method.

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 good aging resistance and high reduction activity 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-fuel ratio wi...

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