Study On The Modification Of CuO/CeO₂ Catalyst Material For Hydrogen Production From Methanol Steam Reforming

Energy is the lifeblood of a country and an indispensable part of human evolution.Hydrogen has been put into industrial application 150 years ago,and now it has been used in aerospace,electronics,industrial raw material production and other fields.Hydrogen combustion has high calorific value,which is the highest calorific value energy except nuclear energy.The products after combustion are environment-friendly and pollution-free,which is in line with the current green chemical theme.Therefore,hydrogen energy has attracted the attention of many researchers.Among many hydrogen production methods,chemical hydrogen production method is relatively mature.Because methanol has high H/C ratio,rich resources,convenient storage and transportation,methanol reforming has become an important means of hydrogen production,which has been paid attention by many countries.However,methanol steam reforming is a complex redox reaction system,so it is urgent to develop a catalyst with high catalytic activity and low CO selectivity.In this paper,Cu based catalysts were prepared by equal volume impregnation with Ce O₂nanomaterials as support,a series of catalysts with high catalytic activity and low CO selectivity were prepared by adding different promoters and changing the content of promoters.The specific research contents are as follows:?1?Nano Ce O₂catalysts were prepared by precipitation method with different cerium sources,and Cu O/Ce O₂catalysts were further prepared by equal volume impregnation method and applied to methanol steam reforming for hydrogen production.Nano Ce O₂and Cu O/Ce O₂catalysts were characterized by SEM,XRD,BET and H₂-TPR.The results show that different cerium sources have an important influence on the structure and properties of Cu O/Ce O₂catalyst and the performance of catalytic methanol steam reforming to hydrogen production.The Cu O/Ce O₂catalyst prepared with cerium nitrate as cerium source has the best catalytic performance for hydrogen production by steam reforming of methanol.When the reaction temperature is 280°C,the molar ratio of water to alcohol is 1.2,the space velocity of methanol steam is 1760 h^-1,the methanol conversion rate is 100%,the hydrogen production rate is 379.7 cm³·kg^-1·s^-1,and the molar content of CO in the reforming gas is 0.83%.?2?The effect of Cu O/Ce O₂catalysts modified by different promoters M?M=Cr₂O₃?Zn O?Y₂O₃?La₂O₃?on the performance of methanol steam reforming to hydrogen production was studied.The results show that the dopant mainly affects the dispersion of Cu O,the reduction property,the interaction between Cu O and Ce O₂,and the oxygen hole content on the surface of Cu O/Ce O₂catalyst.Compared with the four kinds of catalysts,four kinds of catalysts show different catalytic performance.Among them,the Cu O/Ce O₂catalyst with Cr₂O₃has larger specific surface area of Cu,higher dispersion of Cu and more oxygen holes,showing better catalytic activity.?3?On the basis of the research on the excellent catalytic performance of Cu O/Ce O₂catalyst modified by Cr₂O₃,the influence of the content of Cr₂O₃on the structure and performance of Cu O/Ce O₂catalyst was further discussed.The experimental results show that the addition of Cr₂O₃mainly affects the dispersion of active components,the reduction properties,the interaction between Cu O,Ce O₂and Cr₂O₃,and the oxygen hole content on the surface of Cu O/Ce O₂catalyst.The larger the specific surface area of Cu,the lower the reduction temperature,the stronger the interaction,the more oxygen holes on the catalyst surface,the better the catalytic effect.Among them,1.5%Cr₂O₃/Cu O/Ce O₂catalyst has better catalytic activity.When the reaction temperature is 260 ^oC,the molar ratio of water and alcohol is 1.2,and the space velocity of methanol vapor is 1760 h^-1,the methanol conversion rate reaches 100%,the CO content in the tail gas of reforming is 0.15%.Compared with Cu O/Ce O₂catalyst,the methanol conversion rate is increased by 10%,and the CO content in the tail gas of reforming is reduced by 0.34%.