Preparation method Fe/ZSM-5 catalyst for directly decomposing N2O

Abstract

The invention relates to a method for preparing an Fe / ZSM-5 catalyst for directly decomposing N2O, which comprises the following steps: (a), roasting NH4-ZSM-5 zeolite molecular sieves at a temperature of between 500 and 600 DEG C for 2 to 6 hours, cooling and sealing the NH4-ZSM-5 zeolite molecular sieves, and moving the NH4-ZSM-5 zeolite molecular sieves into a drying cabinet; (b), mixing and grinding the zeolite molecular sieves treated in the step a and an iron salt precursor, raising the temperature to be between 300 and 400 DEG C in inert atmosphere, and maintaining the mixture for 1 to 2 hours, wherein the content of iron is 0.01 to 10 weight percent of the total weight of the zeolite molecular sieves and the iron salt precursor; (c), cooling the product in the step b, and hydrolyzing the product in vapor-containing inert atmosphere for 1 to 2 hours at a temperature of between 150 and 200 DEG C; and (d), roasting the product in the step c in oxygen atmosphere for 1 to 2 hours at a temperature of between 500 and 600 DEG C and at a temperature rise speed of between 1 and 8 DEG C per minute.

Description

technical field [0001] The present invention relates to a method for N 2 Preparation method of Fe / ZSM-5 catalyst for direct decomposition of O. [0002] The characteristic of the present invention is that the catalyst is prepared by the liquid-phase ion exchange method in the past, and is prepared by the solid-state ion exchange method, so that the hydrolysis and precipitation of the iron salt precursor can be avoided, and the generation of inert iron oxide can be reduced. In addition by selecting FeCl 3 This easily sublimated precursor can make the distribution of the active phase more uniform. N can be increased by adding Ga, B, P and high temperature roasting 2 active sites for O decomposition, thereby improving its catalytic activity. Background technique [0003] Nitrous oxide (N 2 O), commonly known as laughing gas, as a mild anesthetic used in medical treatment, this colorless gas with a slightly sweet taste has been neglected for a long time. However, since the...

AI Technical Summary

Problems solved by technology

The main disadvantage of the hydrothermal synthesis method is that the content of iron introduced into the framework is limited, and it is difficult to synthesize catalysts with high iron content.

The disadvantage of the liquid-phase ion exchange method is that iron species tend to precipitate in aqueous solution, thereby easily forming inert iron oxide particles; in addition, this method is relatively poor in reproducibility

The disadvantage of chemical vapor deposition (CVD) is that the content of iron species cannot be controlled, and it is easy to generate a large number of iron oxide nanoparticles.

Although the Chinese patent (CN 158296A) also adopts the method of solid phase exchange, it has the disadvantages of inhomogeneous dispersion of the catalyst and easy formation of large pieces of iron oxide.

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