Microporous-mesoporous molecular sieve containing noble metal, preparation method and application to catalytic reduction of p-nitrophenol

Abstract

The invention belongs to the technical field of molecular sieve preparation, and particularly relates to an in-situ preparation method for a microporous-mesoporous molecular sieve containing noble metal. The in-situ preparation method comprises the steps as follows: adding a coupling pore-forming agent, a silicon source, an aluminum source or a titanium source, and an alkali source into a water solution of noble metal nano particles in sequence under the water bath condition; and ageing, drying, crystallizing, drying and carrying out high-temperature calcination to obtain the microporous-mesoporous molecular sieve containing the noble metal. The prepared microporous-mesoporous molecular sieve is provided with a hierarchical pore structure; the noble metal nano particles with high dispersity are covered in situ while a mesoporous structure is generated; and a synthetic method is convenient and simple, saves energy and reduces emission. A multifunctional catalyst prepared with the method integrates the advantages of the microporous channels of the molecular sieve, the transgranular meso pores and the intergranular meso pores of the molecular sieve and the noble metal nano particles, and is more suitable for catalytic reactions of sulfur-containing large molecules such as hydrogen desulfurization and the like.

Description

technical field [0001] The invention belongs to the technical field of molecular sieve preparation, and in particular relates to an in-situ preparation method of a precious metal-containing microporous-mesoporous molecular sieve. Background technique [0002] Microporous molecular sieves are a series of crystalline microporous aluminum silicate materials. Due to their inherent structural characteristics, such as large specific surface area, regular nanoscale pores, highly crystalline micropore walls, and adjustable pore walls The composition makes it widely used in the fields of catalysis, adsorption separation and environment. However, due to its small pore size (<1.5nm), the microporous molecular sieve catalyst greatly limits the diffusion of large-sized reactants and products in its pores, which seriously reduces the utilization efficiency of the catalyst, especially in the upgrading of crude oil. and fine chemicals and other fields of application. In order to solve ...

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Problems solved by technology

Although this method is simple and easy to implement, the organosilane it uses is relatively special, which is poisonous to the body if inhaled; the synthesis cost is high; and sulfur dioxide will be released after high-temperature calcination to pollute the atmosphere

In addition, the material prepared by this method lacks mesoporous channels that facilitate the access of large-sized reactant species to noble metal active sites.

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