Preparation method of t-ZrO2@CuO-ZnO@ZSM-5 double core-shell catalyst

Abstract

The invention discloses a preparation method of a t-ZrO2@CuO-ZnO@ZSM-5 double core-shell catalyst, which includes steps of: preparation of t-ZrO2@CuO-ZnO powder: according to molar ratio of n(TEOS):n(NaAlO2):n(TPAOH):n(H2O)=40-360:1:19:4015, successively adding NaAlO2, TPAOH and TEOS to deionized water under stirring, continuously stirring the mixture uniformly, and aging the mixture for 3 h at room temperature under stirring to form a sol system; according to core-shell mass ratio of t-ZrO2@CuO-ZnO:ZSM-5 = 1:2-2:1, adding the t-ZrO2@CuO-ZnO powder to the system, continuously stirring the mixture uniformly, and performing a hydrothermal reaction in a homogeneous reactor at 170-190 DEG C for 24-48 h at rotation speed of 4 rpm; cooling the product to room temperature, centrifuging the product, and washing the product in deionized water and anhydrous ethanol; and drying the product at 120 DEG C for 12 h and roasting the product at 500-600 DEG C for 3 h. The catalyst can simultaneously increase CO2 conversion rate and low-carbon olefin selectivity in a two-step process of producing low-carbon olefin by hydrogenation of CO2 with methanol.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a kind of t-ZrO 2 Preparation method of @CuO-ZnO@ZSM-5 double core-shell catalyst. Background technique [0002] Copper Zinc Zirconium (CuO-ZnO-ZrO 2 ) three-component copper-based catalyst is the current CO 2 Catalytic hydrogenation synthesis of methanol is the most widely used catalyst with good effect. ZSM-5 molecular sieve is made of SiO 4 and AlO 4 A microporous silica-alumina molecular sieve with tetrahedral units interlaced to form a three-dimensional intersecting channel structure. Because of its rich and adjustable B-acid properties, high specific surface area and unique shape-selective function of microporous products, it is widely used in the process of methanol catalytic cracking to light olefins (MTO). Coupling metal oxides and acidic molecular sieves to prepare bifunctional composite catalysts and apply them to CO 2 In the two-step process of hydr...

AI Technical Summary

Problems solved by technology

It can be seen that the existing research adopts the co-precipitation method and roasts Cu(OH) at 400 °C. 2 -Zn(OH) 2 -Zr(OH) 4 Precursor, Zr(OH) present 4 Dehydration decomposition is not complete, resulting in the carrier effect of t-ZrO 2 The surface chemical properties are not obvious, and the reactivity is low

At the same time, the active components of the existing bifunctional composite catalysts are randomly distributed, and the structure only provides an open reaction environment, which cannot effectively solve the problem of CO 2 CO in the two-step process of hydrogenation and methanol to light olefins 2 Hydrogenation methanol synthesis process and methanol catalytic conversion to light olefins process require different reaction formation and dissociation conversion environmental conditions, resulting in the poor catalytic effect of existing dual-function catalysts