La_2O_3对CuO/CeO_2水煤气变换反应催化剂微观结构及催化性能的影响(英文)  

Effect of La_2O_3 on Microstructure and Catalytic Performance of CuO/CeO_2 Catalyst in Water-Gas Shift Reaction

作　　者：方星[1] 陈崇启 林性贻[1] 佘育生[1] 詹瑛瑛[1] 郑起[1] 

机构地区：[1]福州大学化肥催化剂国家工程研究中心,福建福州350002

出　　处：《催化学报》2012年第3期425-431,共7页

基　　金：国家自然科学基金(20771025);福建省教育厅A类科技项目(JA08021)~~

摘　　要：以La2O3为助剂,采用共沉淀法制备了具有良好催化活性和热稳定性的CuO/CeO2-La2O3水煤气变换反应催化剂,其中,当La2O3含量为2wt%时,催化剂的催化性能最为优异.同时运用X射线衍射、N2吸附-脱附、Raman光谱、程序升温还原等手段,研究了不同含量的La2O3对CuO/CeO2催化剂微观结构及催化性能的影响.结果表明,La2O3助剂进入了载体CeO2的晶格并对CuO/CeO2催化剂的微观结构和催化性能产生了直接影响,适量La2O3的添加可以抑制CuO和CeO2晶格的长大、增强CuO与CeO2间的相互作用、提高催化剂的比表面积、促进CeO2载体中生成更多的氧空位,CuO/CeO2催化剂的催化活性和热稳定性也明显改善.The water-gas shift reaction was used to evaluate a series of La2O3 modified CuO/CeO2 catalysts that were prepared by a parallel co-precipitation method. The catalytic activity and thermal stability improved significantly upon the introduction of La2O3, and CuO/CeO2-La2O3 （2 wt%） gave the highest activity and had the best thermal stability. The microstructure of the as-prepared CuO/CeO2-La2O3 catalysts and/or the CeO2-La2O3 supports was characterized by X-ray diffraction, N2 physisorption, Raman spectroscopy, and temperature-programmed reduction. The results indicate that larger specific surface areas and smaller crystal sizes of CuO and CeO2 result in improved catalytic performance for the as-prepared catalysts. Moreover, the incorporation of La3＋ into the ceria lattice promotes the generation of oxygen vacancies leading to a higher number of moderate copper oxides that interact with surface oxygen vacancies on the surface of the ceria. This enhances the activity and thermal stability of the CuO/CeO2 catalyst.

关 键 词：氧化铜 氧化铈 氧化镧 水煤气变换反应 氧空位 RAMAN光谱 

分 类 号：O643.36[理学—物理化学]