Conversion Of Syngas To Higher Alcohols Over Cu-Co Based Catalyst And Low-temperature Co Oxidation Over Co-Pt Based Catalyst

In recent years,the use of fossil energy such as coal pollutes the environment seriously.The higher alcohol synthesis from syngas（H₂+CO）which come from coal is one of the possible ways for the clean utilization of coal,which has considerable application prospects.Low-temperature CO oxidation can be used not only for air purification,fuel cell and automobile exhaust gas treatment,but also for the catalysts of performance test over probe reaction,which has important practical and theoretical research significance.30 wt.%La Co_0.7Cu_0.3O₃/SiO₂ was prepared by using perovskite as catalyst precursor.After reduction,CuCo-Alloy was obtained,and the syngas was used to directly produce higher alcohols in a slurry bed reactor.Firstly,we investigate the effects of temperature and space velocity conditions on the catalytic performance,and then the catalytic activities in the fixed bed and slurry bed reactors were compared.The experimental results show that when the space velocity is 1200 m L/(g_cat·h),the catalyst has the best HAS selectivity and the selectivity to C₂₊alcohols can reach more than 95%.It has been proved by XRD and TEM that CuCo-Alloy realized the synergistic catalysis of Cu and Co,and La₂O₃ as a HAS promoter could promote the uniform dispersion of CuCo-Alloy.At the same time,we found that the slurry is critical to the selectivity and distribution of the product.Liquid paraffin is a long-chain hydrocarbon,which leads to higher selectivity to hydrocarbons,which is the main reason why the selectivity of higher alcohols cannot be further improved.Furthermore,liquid paraffin is also the most possible reason to extract more C₂₊alcohols,which is also the reason for the higher selectivity of C₂₊alcohols in the total alcohol.The catalytic activity of the catalyst in a fixed bed was found to be slightly better than that of the activity in the slurry bed reactor,due to the heat transfer in the fixed bed reactor is better than that in the slurry bed reactor.Based on the combination of alcohol selectivity and alcohol distribution,we know that the selectivity of C₂₊alcohols in the slurry bed is better than the selectivity of C₂₊alcohols in the fixed bed reactor.A series of different Co-Pt ratio perovskite precursors,La Co_1-xPt_xO₃/SiO₂,were prepared by citric acid complexation-equal volume impregnation method.After reduction,Co-Pt bimetal were supported on La₂O₃ modified SiO₂（Co-Pt/La₂O₃-SiO₂）.The perovskite macromolecular structure can uniformly disperse Co and Pt in atomic size,and the formed Co-Pt bimetal enhances the complete oxidation performance of low-temperature CO through synergistic action.After a series of catalyst performance test experiments,CO was finally screened as a reducing atmosphere and the catalyst Co:Pt=7:1/SiO₂ has good catalytic performance.Then a series of different Ce doped perovskite precursors,La_1-yCe_yCo_0.87Pt_0.13O₃/SiO₂,were prepared by the same method.After reduction,the Co-Pt bimetal was supported on SiO₂ modified by La₂O₃ and CeO₂（Co-Pt/La₂O₃-CeO₂-SiO₂）.The perovskite macromolecular structure can uniformly disperse La and Ce at the atomic size,and the CeO₂ formed after reduction effectively improves the electronic structure of the Co-Pt bimetal and enhances its catalytic performance.