High-energy-ball-milling-method SCR molecular sieve catalyst and preparation method thereof

Abstract

The invention relates to a composite oxide iron-based molecular sieve SCR catalyst and a preparation method thereof. The composite oxide iron-based molecular sieve SCR catalyst is characterized in that the preparation method comprises the following steps: uniformly mixing copper oxide, iron oxide and co-catalyst metal oxide materials with molecular sieves by using a high energy ball milling method; adding an active component guiding-in agent and a surface dispersant to carry out impregnation; and ball-milling, drying, grinding and calcining to obtain the composite oxide iron-based molecular sieve SCR catalyst. The composite oxide iron-based molecular sieve SCR catalyst is used for catalytically purifying NOx in motor vehicle exhaust. The preparation process of the catalyst is simplified, the high energy ball milling method is adopted, the active component guiding-in agent and the surface dispersant are added so that metal active components are uniformly distributed in molecular sieve holes and on surfaces of the molecular sieve holes, during calcining, the metal oxide has abundant valence states, and the NOx conversion efficiency is high; and by the added co-catalyst metallic compound, sulfur resistance is improved, meanwhile, the co-catalyst metallic compound can also serve as an active component, NO-to-NO2 conversion is strengthened, the activity of the SCR catalyst is improved remarkably, and the actual application value is high.

Description

technical field [0001] The invention relates to a high-energy ball milling SCR molecular sieve catalyst and a preparation method thereof, in particular to a composite oxide iron-based zeolite molecular sieve catalyst material for catalytic purification of diesel engine exhaust nitrogen oxides (NOx) selective catalytic reduction (SCR) and its Preparation. Background technique [0002] Many studies have shown that metal element modified zeolite molecular sieve catalysts, iron-based, copper-based molecular sieve catalysts and copper-iron composite molecular sieve catalysts have high catalytic purification activity for nitrogen oxides in automobile exhaust, and have broad application prospects. [0003] Zeolite molecular sieve has the characteristics of environmental friendliness, high specific surface area, and excellent heat resistance, and is gradually becoming the mainstream material of SCR catalyst. Through different metal modifications, it meets the needs of motor vehicle...

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Problems solved by technology

[0008] CN101121526A patent discloses a preparation method of nano-Fe-ZSM-5 zeolite molecular sieve. The method is a hydrothermal synthesis method, and the temperature is kept at 70-120°C for 20-60h, and then the temperature is raised at 140-220°C for 10-80 hours. Long time, high temperature, difficult to mass production

[0014] Although the above-mentioned preparation of Fe-based molecular sieve catalysts improves the performance of the catalysts to varying degrees, there are still the following problems: (1) The reaction time of the hydrothermal method is long; (2) The temperature and pressure of the reactor are high, and the control of the reaction conditions is strict; ( 3) Harmful waste gas is produced during the calcination of the organic template agent during the preparation process

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