Preparation method of automobile tail gas purifying catalyst

Abstract

The invention discloses a preparation method of an automobile tail gas purifying catalyst, relating to a preparation method of a catalyst. The method disclosed herein comprises the following steps: adding pseudo-boehmite to decationized water, uniformly stirring at room temperature, then adding diluted hydrochloric acid to adjust the pH value to 5-6, aging for 1h at room temperature, drying at 130 DEG C, and roasting at 650 DEG C for 2h to obtain alumina; saturatedly dipping the alumina in a lanthanum nitrate, cerium nitrate and zirconium oxychloride solution, wherein the molar ratio of CeO2 to ZrO2 is 1:1; drying at 130 DEG C, and roasting at 950 DEG C for 2h to obtain rare earth composite alumina; saturatedly dipping the rare earth composite alumina in a Pt, Rh noble metal solution, drying at 130 DEG C and roasting at 650 DEG C for 2h, then adding decationized water and uniformly stirring for 30min to obtain a catalyst slurry, and coating on a 65 pore / cm<2> iolite cellular carrier. The gamma-Al2O3 prepared by the method has high specific surface area and large pore volume, low ignition temperature, wide air-fuel ratio window and high conversion rate.

Description

technical field [0001] The invention relates to a preparation method of a catalyst. Background technique [0002] In the research and development of automobile exhaust purification catalysts, due to the γ-Al 2 o 3 With a high specific surface area, it is currently one of the most widely used catalyst supports. But γ-Al 2 o 3 The thermal stability of γ-Al has been bothering people, especially in the presence of water vapor at high temperature, γ-Al 2 o 3 Phase change and sintering are prone to occur, which greatly reduces the specific surface area of ​​the catalyst carrier, resulting in a rapid decrease in the activity of the supported catalyst and shortening the service life of the catalyst. At present, my country's environmental protection regulations require that the exhaust gas catalysts of automobiles should be matched with the whole vehicle after 80,000 km driving test or rapid aging at 760°C for 100 h on the engine bench, and tested according to the test procedur...

AI Technical Summary

Problems solved by technology

But γ-Al 2 o 3 The thermal stability of γ-Al has been bothering people, especially in the presence of water vapor at high temperature, γ-Al 2 o 3 It is prone to phase change and sintering, which greatly reduces the specific surface area of ​​the catalyst carrier, resulting in a rapid decrease in the activity of the supported catalyst and shortening the service life of the catalyst