CHA structure molecular sieve, synthesis method, nitrogen oxide selective reduction catalyst and application

Abstract

The invention discloses a CHA structure molecular sieve and a synthesis method thereof, and a nitrogen oxide selective reduction catalyst and application thereof, and belongs to the field of chemicalsynthesis technology and application thereof. An N,N,N-trialkyl-(naphthyl-1-yl)quaternary ammonium onium compound is adopted as an organic template agent to synthesize the CHA structure molecular sieve, the molar ratio range of silicon dioxide to aluminum oxide is 6-80, the average grain diameter is smaller than or equal to 500 nm, the total specific surface area is larger than or equal to 400 m2 / g, the total pore volume is larger than or equal to 0.20 ml / g, the micropore volume is larger than or equal to 0.10 ml / g, and the grain diameter in the crystal face (-210) direction of the molecular sieve is 50-160 nm. The molecular sieve provided by the invention has high hydrothermal stability under the condition of no large crystal grains, and shows high nitrogen oxide reduction characteristicsafter being exposed at high temperature and high humidity, especially shows high nitrogen oxide reduction characteristics in a temperature range of 200-550 DEG C.

Description

technical field [0001] The invention relates to a molecular sieve with a CHA structure and a synthesis method, a nitrogen oxide selective reduction catalyst and its application, and belongs to the field of chemical synthesis technology and its application. Background technique [0002] The silica-alumina zeolite molecular sieve is a CHA-type topological structure with a three-dimensional pore structure and orthogonal symmetry. The one-dimensional main channel is composed of double eight-membered rings, the pore size is 0.38nm×0.38nm, and the skeleton density is 14.5. The topological structure of CHA molecular sieve is composed of double 6 rings (d6r) connected by 4-membered rings to form a large cha cage. The d6r crystal plane faces the cha large cage. Cu ions can be stabilized in d6r at high temperature, allowing Cu ions to migrate. It is also the unique physical and chemical characteristics of small-pore molecular sieves with SCR reaction potential. In the literature (J.P...

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the SCR catalyst using synthetic molecular sieves loaded with iron and copper in the prior art to be active at low temperatures through the hydrothermal durability test. Lower defects, providing a copper-based SCR catalyst with high activity at low temperature after hydrothermal durability test and its preparation method

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