溶胶-凝胶法制备K-Co-Mo催化剂的结构及其合成低碳醇性能研究──钾含量的影响  

Catalytic Properties and Structure of the K-Co-Mo Catalysts Prepared by Sol-Gel Method for Mixed Alcohol Synthesis — Effect of K Content

作　　者：鲍骏[1] 卞国柱[1] 伏义路[1] 

机构地区：[1]中国科学技术大学化学物理系,合肥230026

出　　处：《分子催化》1999年第5期357-361,共5页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金;安徽省自然科学基金

摘　　要：采用溶胶－凝胶法制备钴钼氧化物催化剂， 并将其浸渍不同量的Ｋ２ＣＯ３ 后进行硫化． 使用Ｘ－射线衍射（ＸＲＤ）和激光拉曼光谱（ＬＲＳ）对氧化态及硫化态样品的结构进行表征， 同时测试硫化态样品合成低碳混合醇的活性． 结构表征的结果表明， 不含钾的氧化态样品， 以ＣｏＭｏＯ４ 形式存在； 含钾样品中， 助剂钾与钴钼复合氧化物之间存在较强的相互作用， 有多种Ｋ－Ｍｏ－Ｏ物种生成， 且使硫化态物种趋于稳定。活性测试结果表明， 所制备催化剂的合成醇活性和选择性较高，其中Ｋ／Ｍｏ 比为０．４ 的样品活性最好， 在Ｔ＝ ３１０ ℃， ｐ ＝ ５．０ ＭＰａ， ＧＨＳＶ＝ ４ ８００ ｈ－ １的条件下， 低碳醇的时空产率达１２４ ｇ／（Ｌ·ｈ）， 明显高于文献报道的水平．A kind of Co\|Mo complex oxide has been successfully prepared by the sol\|gel method with citric acid as complexant, which has been promoted with different K loadings by impregnating method and then sulfided. The activity over the sulfided samples for the synthesis of mixed alcohols from CO hydrogenation was investigated in the conditions of p=\{5.0 MPa,\} T=310 ℃ and GHSV=4 800 h -1 . The results show that the optimum K content is K/Mo (atomic ratio) =0.4, on which the space\|time\|yield and the selectivity toward mixed alcohols are obviously higher than the published results. The structures of the oxidic and sulfided samples were characterized by XRD and LRS. The results from XRD show that Co\|Mo complex oxide exists as the CoMoO 4 phase. While K 2CO 3 is added, the CoMoO 4 phase is destroyed and some K\|Mo\|O species are formed. After sulfidation, Co species exist as Co 9S 8 and Mo as MoS 2 crystallites. Potassium promoter can stabilize the sulfided states, but excessive potassium covers the active sites on the catalyst surface.

关 键 词：溶胶凝胶法 催化剂 低碳醇 钾含量 氧化物催化剂 

分 类 号：O643.36[理学—物理化学] TQ223.12[理学—化学]