The Preparation Of Copper-based Catalyst Supported On Mesoporous Al₂O₃ And Its Catalytic CO/CO₂ Co-hydrogen Reaction

The environmental problems caused by the massive emission of CO₂ have seriously threatened the survival and development of mankind.CO is toxic,and when the human body inhales too much CO,it can cause poisoning,severe death.The blast furnace waste gas in steelmaking and iron smelting contains a lot of CO and CO ₂.If it is discharged into the environment,it not only causes environmental problems,but also wastes a large amount of carbon source.CO and CO₂ can be catalyzed by catalysts into organic compounds such as methanol,formic acid,ethanol and dimethyl ether?D ME?.Among these catalysts,copper-based catalyst is more studied.In this paper,mesoporous copper-based catalyst was prepared by impregnation and precipitation method,mesoporous Al₂O₃ as the support.And influence of the calcination temperature of the support,copper content,preparation methods,the introduction of Zn O,roasting time of catalyst and reaction gas composition on structure and catalytic performance of catalysts was investigated.The results show that the roasting temperature of the support can affect the structure of the soppor,and the amorphous support is more active.Precipitation method and the addition of Zn O can introduce highly active precursor phase into the catalyst.The roasted and reducted catalyst used in CO/CO ₂co-hydrogenation resulted in the conversion of the reaction gas from the initial 10%to about 50%.The roasting time study of mesoporous Cu O/ZnO/Al₂O₃ catalyst found that with the roasting,The morphology of surface oxides has changed significantly;coppe r is reducted easily;acid site of catalyst increased,and basic sites decreased.In CO/CO ₂co-hydrogenation,the roasting time of catalyst mainly affects the selectivity of DME and methanol.It was found that their selectivity was mainly controlled by the number of acid and basic sites.The experimental results of gas composition change show that the addition of CO₂ can greatly promote the conversion of CO,and CO can restrain the RWGS reaction of CO₂ better.In situ IR results show that in CO/CO₂ co-hydrogenation on Cu O/Zn O/Al₂O₃ catalyst,firstly,CO₂ forms formate and methoxy intermediate,which generate methanol and water,then produced water reacts with CO to generate CO₂,and CO₂ is the reactant for the next step reaction,which constitute a cycle.According to the review,Cu O/Zn O/Al₂O₃ catalyst is used in CO/CO₂co-hydrogenation,and the gas utilization ratio is high.The selectivity of methanol and DME can be controlled by controlling the roasting time and gas composition of the catalyst.