Preparation Of Bimetallic Oxide Solid Solution Catalyst And Application Of CO₂ Hydrogenation To Methanol By Microfluidic Continuous Coprecipitation

Regarding the process of CO₂ hydrogenation to methanol,aiming at the technical bottleneck of the low reaction efficiency of the existing catalytic system,in view of the special oxygen vacancy high temperature activation CO₂ mechanism of the bimetal oxide catalyst,the thesis proposes to use Zn O as the hydrogenation active component,and to use microfluidic continuous co-precipitation method to carry out the preparation,characterization and performance evaluation of Zn Zr O_X and Zn In O_X bimetal solid solution structure catalysts respectively.The microfluidic continuous co-precipitation method was used to investigate the effects of different Zn Zr O_X bimetallic oxide Zn O solid solution components on the catalyst phase composition and the catalytic performance of CO₂ hydrogenation to methanol;Using traditional coprecipitation method,impregnation loading method and physical blending method to prepare bimetal oxide as reference,with the help of XRD,XPS,XRF,HRTEM,SEM,DRUV-vis,N₂ adsorption-desorption,O₂-TPD,H₂-TPR,CO₂-TPD and other means to study the structure-activity relationship of 14%Zn Zr O_Xcatalyst;The process conditions of microfluidic continuous co-precipitation preparation and the reaction conditions of CO₂ hydrogenation to methanol were optimized.The results show that the microfluidic continuous co-precipitation method has a Zn O solid solution content of 14%,the microfluidic reactor tube is 7 m long,and the two-phase flow rate is 20 ml/min,and 80?aging 2 h,baking at 500?for 3 h,the prepared 14%Zn Zr O_X bimetallic oxide solid solution catalyst has excellent catalytic performance of CO2 hydrogenation to methanol,Under the reaction conditions of 3 Mpa,temperature of 320°C,GHSV=12000 ml g^-1h^-1,CO₂ conversion rate,methanol selectivity and methanol space-time yield STY reached 9.2%,94.1%and 0.36 g _{Me OH}h^-1g^-1_cat,respectively.Using microfluidic continuous co-precipitation method,the effects of different Zn In O_X bimetallic oxide Zn O solid solution content and preparation methods on the catalytic performance of CO₂ hydrogenation to methanol were investigated,with the help of XRD,XPS,HRTEM,DRUV-vis,O₂-TPD,H₂-TPR,CO₂-TPD and other methods were used to analyze and characterize the physical and chemical properties of the catalyst,and the structure-activity relationship of the Zn In O_X solid solution structure catalyst was studied;the process conditions for the preparation of microfluidic continuous co-precipitation and the CO₂ hydrogenation to methanol were optimized Reaction conditions.The results show that,using microfluidic continuous co-precipitation method,the content of Zn O solid solution components is 20%,the length of the tube in the microfluidic reactor is 7 m,the two-phase flow rate is 20 ml/min,aging at 80?for 2 h,baking at 500?for 3 h,the 20%Zn In O_X bimetal oxide solid solution catalyst has excellent catalytic performance for CO₂ hydrogenation to methanol.Under the reaction of 3Mpa,temperature of 380°C,GHSV=14400 ml g^-1h^-1,CO₂ conversion rate,methanol selectivity and methanol space-time yield STY reached 24.0%,88.0%and 1.04 g _{Me OH}h^-1g^-1_cat,respectively.