制备方法对CuFe负载介孔SiO_(2)催化剂合成气制低碳醇催化性能的影响

Effect of preparation methods on catalytic performance of CuFe supported mesoporous SiO_(2) catalyst for syngas to higher alcohols

Cu-Fe基催化剂被广泛应用于合成气制低碳醇反应中,而改进催化剂制备方法是改善催化剂反应活性和优化产物选择性的重要途径。采用水热合成法、超声浸渍法和沉积沉淀法分别制备了一系列CuFe负载介孔SiO_(2)催化剂,并结合N_(2)吸/脱附、XRD、TEM、XPS、H_(2)-TPR和CO-TPD表征,考察了制备方法对催化剂物化性质与反应性能的影响。结果表明,采用水溶液超声浸渍法制备的CuFe/SiO_(2)-IW催化剂具有最大的比表面积和孔容,在较低的温度下更容易被还原,CO吸附能力较强,催化活性最高。此外,CuFe/SiO_(2)-IW催化剂具有最强的CO非解离活化能力,可以提高总醇选择性。同时,该催化剂表面存在较强的CuFe协同效应,有利于提高C_(2+)OH的选择性。在240℃、5 MPa、空速为5000 h^(-1)的反应条件下,CO转化率为22.9%,总醇选择性为33.8%,其中C_(2+)OH占比60%。

Cu-Fe based catalysts are widely used in syngas to higher alcohols,and improving the preparation method of catalyst is an important way to improve the catalytic activity and optimize the product selectivity.A series of CuFe supported mesoporous SiO_(2) catalysts were prepared by hydrothermal method,ultrasonic impregnation method and deposition precipitation method respectively.Combined with N_(2) adsorption/desorption,XRD,TEM,XPS,H_(2)-TPR and CO-TPD characterization,the effects of preparation met hods on the physicochemical properties and reaction performance of the catalysts were investigated.The results show that the CuFe/SiO_(2)-IW catalyst prepared by aqueous solution ultrasonic impregnation method has the largest specific surface area and pore volume,which is easier to be reduced at lower temperature and has strong CO adsorption capacity,thus showing the highest catalytic activity.In addition,CuFe/SiO_(2)-IW catalyst has the strongest CO non-dissociative activation ability,which can improve the selectivity of total alcohols.At the same time,there is a strong CuFe synergistic effect on the surface of the catalyst,which is conducive to improving the selectivity of C_(2+)OH.Under the reaction conditions of 240℃,5 MPa and space velocity of 5000 h-1,the CO conversion rate was 22.9%,and the selectivity of total alcohols was 33.8%,in which C_(2+)OH accounted for 60%.