Cu-Co负载量对Cu-Co基催化剂催化CH_4-合成气梯阶转化合成C_2^+含氧化合物的影响  

Effect of Cu-Co Loading on Catalytic Performance of Cu-Co /TiO_2 Catalysts in Step-wise Conversion of CH_4 and Syngas

作　　者：彭芬[1] 黄伟[1] 韩涛[1] 

机构地区：[1]太原理工大学煤科学与技术教育部和山西省重点实验室,太原030024

出　　处：《高等学校化学学报》2013年第11期2587-2593,共7页Chemical Journal of Chinese Universities

基　　金：国家"九七三"计划项目(批准号:2005CB221204);国家自然科学基金(批准号:20676085)资助

摘　　要：以TiO2纳米粒子为载体,采用等体积浸渍法制备了Cu-Co双金属催化剂,考察了不同Cu/Co质量比和不同Cu-Co含量的双金属催化剂对CH4-合成气梯阶转化直接合成C+2含氧化合物的影响.在连续式步阶固定床反应装置上进行了催化性能评价.实验结果表明,当Cu-Co含量为18%,Cu/Co质量比为2∶1时,CuCo/TiO2的C+2含氧化合物产物的时空收率最大,为19.92 mg·g-1cat·h-1,选择性为67.76%.研究表明,金属组分之间和载体与金属组分之间的相互作用、金属组分良好的分散性和还原性是促进活性位的形成和提高催化剂活性的原因;催化剂表面高度分散的CuO微晶有利于催化加氢和脱氢反应的进行,对CH4-合成气转化反应有重要的促进作用.另外,弱酸和中强酸有利于CH4-合成气转化反应,而强酸对该反应有抑制作用.A series of Cu-Co/TiO2 catalysts with different Cu-Co loadings and Cu/Co mass ratio was prepared by equal volume impregnation. The catalysts performances were investigated for the direct synthesis of C~ oxy- genates from CH4 and syngas by a step-wise reaction technology. Several techniques, including N2 physical adsorption-desorption（ BET）, temperature-programmed reduction of hydrogen （ H2-TPR）, X-ray diffraction （XRD）, temperature-programmed desolption of hydrogen nitride （NH3-TPD） and temperature-programmed desorption of CO （CO-TPD） were used to characterize the catalysts. The results show that among all the catalysts, 18% （Cu12-Co6 ）/TiO2 has the highest catalytic activity, the formation rate and selectivity of C~ oxy- genates reached 19.92 mg ~ gc-~lt ~ h-1 and 67.76%, respectively. It is concluded that there is the interaction between the TiO2 and the active metal Co-Cu as well as the good dispersion in the catalyst, the catalyst has high activity; Highly dispersed micro-crystal CuO that is conducive to catalytic hydrogenation and dehydrogen- ation reaction can promote the conversion of CH4 and syngas. Besides, weak acid and mediate strong acid are beneficial to the conversion of CH4 and syngas, but strong acid produces inhibitory action to the reaction.

关 键 词：Cu-Co催化剂 CH4-合成气 梯阶转化 

分 类 号：O643[理学—物理化学]