Synthesis Of Methanol From CO₂and H₂O By Non-equilibrium Anion Cooperating With Catalysts

Carbon dioxide has a major impact on people’s production and life:as one of the main greenhouse gases,its content in the atmosphere is increasing year by year,leading to sea level rise,climate warming,frequent extreme weather,endangering people’s survival.From another perspective,carbon dioxide is a kind of C₁resources,and the development of efficient industrial methods for carbon dioxide capture and utilization can turn waste into treasure and realize the recycling of resources.The hydrogenation of CO₂to methanol is a research hotspot in the conversion and utilization of carbon dioxide.The traditional methods use H₂as a hydrogen source for carbon dioxide to produce methanol,which requires harsh conditions such as high temperature and high pressure.In this study,a negative corona plasma is used in conjunction with the catalysts,and water vapor is used as a cheap hydrogen source.Under relatively mild conditions,carbon dioxide is catalyzed and activated to obtain the target product methanol,which can realize the resource utilization of the reactants.This paper investigates the performance of different catalysts to catalyze the reaction of CO₂and water vapor to methanol under the action of negative corona plasma.The effects of catalyst types and preparation methods,CO₂flow rate,discharge current,reaction temperature,water vapor flow rate and other factors were investigated.The results show that:for the combined system of ZnO-Zr O₂solid solution and negative corona plasma,when the reactor temperature was 150℃,the discharge current was 4.17 A,the CO₂flow rate was 20 m L·min^-1,the water vapor flow rate was 28.74 m L·min^-1,and the Znmolar ratio n（Zn）/n（Zr）was 7:93,the maximum output of methanol was 33.56μmol·h^-1,which was 1.4 times the sum of the methanol output of the single plasma and the single catalyst system.In the combined system of In₂O₃and negative corona plasma,the In₂O₃catalyst prepared by the hydrothermal method had better effect than the catalyst prepared by the direct calcination method.At normal pressure,the temperature was 190℃,the discharge current was 3.33 A,and the CO₂flow was 20 m L·min^-1and the water vapor flow rate was28.74 m L·min^-1,the methanol output could reach 37.37μmol·h^-1,which was twice the yield of methanol of the indium oxide catalyst prepared by the direct calcination method,and was 2.3 times the sum of the methanol output of the plasma alone and the single catalyst system under the same condition.The output of methanol increased with the increase of the reaction current and the flow of water vapor,and decreased with the increase of the flow rate of carbon dioxide.The increase in methanol production indicated that the combination of catalysts（7%ZnO-Zr O₂,S-In₂O₃）and plasma has a significant synergistic effect.Through a variety of catacterization methods,the mechanism of the reaction of CO₂and H₂O catalyzed by combination of two different catalysts with plasma is analyzed.We believe that under the conditions of negative corona plasma reaction,the distance between ZnO-Zr O₂crystal planes increases and oxygen vacancies increase,which enhances the chemical adsorption of the catalyst performance.The carboxylate produced by the combined action of negative corona plasma and catalyst is the key intermediate product in the production of methanol.The In₂O₃catalyst prepared by hydrothermal method can exist stably under negative corona conditions.The strong adsorption performance of CO₂on the surface of In₂O₃and the better H₂absorption capacity are important reasons for increasing methanol production.