合成低碳醇用超细Mo-Co-K催化剂的XPS研究

XPS Study of Ultrafine Mo-Co-K Catalyst for Synthesis of Lower Alcohols

采用XPS技术对氧化态及还原态超细Mo Co K催化剂进行了研究 .结果表明 ,在氧化态超细Mo Co K催化剂中 ,钼和钴分别以Mo6 +和Co2 +物种存在 ,催化剂中各物种之间存在着相互作用 ;随着Co/Mo比的增大 ,还原态催化剂中Mo4+物种的含量逐渐增大并出现极大值 ;催化剂上合成低碳醇反应性能与其表面的Mo4+物种有关 .将催化剂表面的Mo4+物种含量与其合成低碳醇选择性进行关联 ,发现二者存在着很好的对应关系 .此外 ,对超细Mo Co

A series of ultrafine Mo Co K catalyst samples with different Co/Mo ratios were investigated. The catalyst samples were characterized by XPS and the catalytic performance of the catalyst for synthesis of lower alcohols was investigated. The XPS results indicated that the molybdenum exists as Mo 6+ and (Mo 6+ +Mo 4+ ) in the unreduced and reduced catalyst, respectively, while the cobalt exists as Co 2+ in both unreduced and reduced catalyst. An interaction between the Mo species and Co species exists in the catalyst. The XPS results revealed that the content of Mo 4+ species has a maximum value at n (Co)/ n (Mo)=0 13. A linear relation between the alcohol selectivity and the Mo 4+ content in the reduced catalyst leads to the conclusion that Mo 4+ species in the catalyst may be the active sites for synthesis of lower alcohols.