Synthesis Of Core Shell CuZnZr@H-ZSM-5 And Its Catalytic Performance For Carbon Dioxide Hydrogenation

The intensification of the greenhouse effect has raised higher requirements for the adsorption and utilization of carbon dioxide.The research of catalytic hydrogenation has been widely concerned with the most added value.The main focus of the present study is to improve the conversion rate of raw gas and the selectivity of the product,the deactivation energy of the catalyst and the catalytic activity of the catalyst.In this research,we use CO2+H2 as raw material,and take one-step method to synthesize two methyl ether,the future automobile clean fuel.The methanol catalyst is composed of copper,zinc and zirconium,and the dehydration used H-ZSM-5 zeolite as a component.In order to improve the selectivity of two methyl ether and the anti-inactivation performance of the catalyst,this study used aluminum precursor to induce the synthesis of nuclear shell material CZZ@HZSM-5,and compared the results obtained by the chemical process simulation software Aspen with the results obtained from the experiment to obtain the catalytic activity of the catalyst.CZZ,which was composed of CuO,ZnO and ZrO2,was synthesized by coprecipitation method.The pore structure is dominated by mesopores,and appeared like the lamellar morphology,of which the specific surface area is 54 m2/g.When potassium bicarbonate was used as precipitant,polyvinylpyrrolidone as a dispersant,reverse coprecipitation method was used,aged for 2 h,the CZZ obtained was the most thinning and dispersing,has the highest crystallinity and the largest surface area.And the morphology and distribution was uniform,meanwhile the agglomeration and adhesion phenomenon was less appears.The core-shell structure was obtained by hydrothermal synthesis of aluminum source precursor.SEM showed that H-ZSM-5 was encapsulated in CZZ,and the polymerization structure was formed.When CZZ was used as the nuclear material,inorganic aluminum source was used,and four propyl ammonium hydroxide as ammonium source,the CZZ@H-ZSM-5 synthesized has the best morphology,the surface area is the largest and the ammonium load is the best.When CZZ was used in catalytic hydrogenation,the conversion rate of carbon dioxide is up to 20%,methanol selectivity is up to 50%,methanol synthesis reaction and reverse steam conversion reaction were competing under the 3,5 MPa.When CZZ@H-ZSM-5 was used in catalytic hydrogenation,the conversion rate of carbon dioxide is 15%,the selectivity of dimethyl ether up to 80%,methanol selectivity is up to 65%,and almost no CO is produced under 5 MPa.Compared with CZZ,the adoption of the nuclear shell structure greatly improves the selectivity of the product.XRD shows that CZZ in the catalyst still has reactivity after the reaction.It showed that the ability to resist deactivation has also been greatly improved.Comparing the hydrogenation result obtained using CZZ@H-ZSM-5 with the results obtained by Aspen simulation in this study,the role of the catalyst is to change the relationship in the complex reaction system,promoting the reaction as a whole to the direction of two methyl ether.But this effect requires a certain temperature and pressure condition.The reaction law of the complex temperature and pressure conditions is simulated by Aspen,and richer conclusions were obtained.