钾修饰的MoO_3/SiO_2催化剂的XRD和TPR表征  

XRD and TPR Studies on MoO_3/SiO_2 Catalysts Doped with Potassium

作　　者：王琪[1] 郝影娟[1] 陈爱平[1] 姚光华[1] 杨意泉[1] 

机构地区：[1]厦门大学化学化工学院,厦门361005

出　　处：《应用化学》2007年第5期561-564,共4页Chinese Journal of Applied Chemistry

基　　金：厦门市创新基金计划项目(350Z20031082)

摘　　要：采用XRD和TPR测试技术表征了一系列不同K与Mo摩尔比的MoO3/K2O/SiO2催化剂。XRD表征结果显示,随着元素K的加入,多钼物种逐渐被破坏,最终形成了单钼的K2MoO4物种。TPR表征显示,催化剂表面的钼物种有2种结构,即八面体的Mo(Oh)和四面体的Mo(Td)。八面体Mo(Oh)的还原峰在770 K附近,而四面体Mo(Td)还原峰在1 000 K附近;无K的MoO3/SiO2催化剂的低温还原峰出现在840 K,少量元素K的添加削弱了Mo与SiO2之间的作用,使得低温还原峰温度降低到770 K附近;随着元素K添加量的进一步增加,Mo(Oh)物种逐渐减少而Mo(Td)物种逐渐增多,从而使得催化剂表面的Mo更难被还原。高硫合成气制甲硫醇的活性随着钼基催化剂八面体(Oh)钼物种的增加而增加。A Series of MoO3/K2O/SiO2 catalysts with different K/Mo molar ratios were prepared and characte-rized using XRD and TPR. XRD characterization shows that with the increase of potassium content, polymolybdate species depolymerizes progressively, leading to the formation of K2MoO4 species. TPR characterization shows that there are two kinds of Mo coordination species, namely octabedral molybdenum（ Mo（ Oh ） ） and tetrabedron molybdenum（ Mo（ Td ） ）. The reduction peak of Mo（ Oh ） was found to appear at about 770 K, and that of Mo （ Td ） at about 1 000 K. The addition of a small amounts of potassium can decrease the interaction between Mo and SiO2 and lower the reduction temperature of Mo（ Oh ） by about 70 K. With the increase of potassium content, the amount of Mo （ Td ） increased, while that of Mo （ Oh ） decreased, leading to the more difficult reduction of Mo. The performance of the catalysts for methyl mercaptan synthesis from high H2 Scontaining syngas showed that with the increase of Mo（ Oh ）, the activity of the catalyst increased.

关 键 词：MoO3/K2O/SiO2催化剂 XRD TPR 高硫合成气 甲硫醇 

分 类 号：O643[理学—物理化学]