Study On Modification Of CuO-ZnO-ZrO₂ Catalyst For Hydrogenation Of CO₂ To Methanol

At present,with the continuous development of social economy and the gradual increase of population,the amount of CO₂ in the atmosphere caused by the burning of fossil fuels and human activities also increases year by year,which leads to the intensification of greenhouse effect,and then results in climate change and global warming.As a rich and cheap carbon resource,CO₂ can be converted into useful chemicals and fuels by catalytic hydrogenation technology such as methanol,which is one of the effective ways to rationally use CO₂ and alleviate the negative impact caused by CO₂ emissions.In the technique of methanol synthesis from CO₂ hydrogenation,the research and development of high performance catalyst is of great significance,and the doping of promoters is one of the important factors that affecting the properties of methanol synthesis catalyst.This paper mainly studies the influence of different additives on the performance of CuO-ZnO-ZrO₂ catalyst.The relevant research contents and results are shown as follows:1.CuO-ZnO-ZrO₂ catalysts modified with different group VIB transition metal oxides?1?A series of CuO-ZnO-ZrO₂-M_xO_y?M=Cr,Mo,W?catalysts were prepared by a co-precipitation method.The effects of Cr/Mo/W metal oxides on the performance of the obtained catalysts were studied.The results indicated that the methanol selectivity and yield of the CuO-ZnO-ZrO₂ catalyst noticeably increased by the addition of MoO₃ and WO₃,but slightly decreased by Cr₂O₃ doping.?2?The CuO-ZnO-ZrO₂ catalyst modified by WO₃ was prepared by co-precipitation method.The influence of WO₃ content on the properities of the CuO-ZnO-ZrO₂-WO₃catalysts has been investigated.It was found that both CO₂ conversion and methanol selectivity of the CuO-ZnO-ZrO₂ catalyst was enhanced by the addition of small amount of WO₃?2 and 5 at.%?.However,the activity was significantly decreased by the addition of excessive WO₃?20 at.%?.The activity was related to the amount of weak basic sites,specific surface area of metallic Cu,and reducibility of the catalyst.2.Modification of CuO-ZnO-ZrO₂ catalysts by oxides of group IIIA boron group?1?The B/Al/Ga/In modified CuO-ZnO-ZrO₂ catalyst was prepared by improved citric acid complexation,and the effects of the four oxide additives on the catalytic performance were discussed.The results indicate that the specific surface area of metallic copper can be significantly increased by the introduction of Al,which further promotes the high activity of methanol synthesis.In additive can strongly reduce the catalytic activity.?2?The CuO-ZnO-ZrO₂ catalysts modified by Al were prepared by citric acid complex method with different improvements.The effects of four preparation methods,i.e.water as the solvent,water as the solvent+hydrothermal treatment,ethanol as the solvent,and ethanol as the solvent+ethanol heat treatment,on the catalytic performance were studied.The results indicated that the catalyst,which prepared by using ethanol instead of water as a solvent,can improve the performance of the catalyst,but no matter which solvent is used,the effect of the solvent heat treatment of the catalyst precursor is small.