Molecular sieve scr catalyst and preparation method

Abstract

The invention discloses a molecular sieve SCR catalyst and a preparation method, the preparation method comprising the steps of: (1) heating deionized water to 60-90 °C, and adding a soluble copper salt and an additive to stir and dissolve the same to prepare a copper solution; (2) heating the deionized water to 20-90 °C, adding a soluble yttrium salt to dissolve the same, and when maintaining the temperature, adding a molecular sieve with a silicon-aluminum ratio of ≤24 and stirring the same; when maintaining the temperature, adding a copper solution and stirring to perform ion exchange; (3) cooling the solution after the ion exchange in step (2), adding an adhesive, stirring and ball-milling the mixture, and standing to obtain a slurry; (4) coating the slurry onto a support, drying and then calcining to obtain a molecular sieve SCR catalyst. The catalyst prepared according to the present invention by using a small pore molecular sieve material with a lower silicon-aluminum ratio and adding yttrium as a second active component exhibits excellent catalytic activity for NOat low and high temperatures, and has a wide active temperature window, high hydrothermal stability and good hydrocarbon resistance.