不同方法制备的硫化态K—Co—Mo催化剂的EXAFS研究

采用共沉淀法和溶胶－凝胶法制备了同组分的硫化态K－Co-Mo催化剂，并用EXAFS研究了体系中Mo原子和Co原子的局域配位情况，结果表明，硫化态K-Co-Mo样品中Mo原子以类似于MoS2结构的物种存在，而Co原子除了以Co9S8形式存在外，还以一种Co-Mo-S相的形式存在，Co-Mo-S的晶相结构与MoS2类似，结合活性测试 结果认为Co-Mo－S的形成促进了样品催化活性的提高，此外，EXAFS结果还表明，不同制备方法对K－Co-Mo样品中Mo物种晶粒尺寸具有较大的影响，而对Co9S8粒子则影响不明显，其中，采用溶胶－凝胶方法制备，并且在氩气中处理过的样品中Mo物种具有最小的晶粒尺寸。

An EXAFS Study of Sulfided K-Co-Mo Catalysts Prepared by Different Method

A kind of sulfided K Co Mo catalyst, prepared by sol gel and precipitation method respectively, was characterized by EXAFS technique. The results indicate that, in the sulfided samples, the Mo atoms exist as MoS 2 like species, the Co atoms exist not only as Co 9S 8, but also as a kind of Co Mo S phase, which almost has the same structure as MoS 2. Combining the activity results, it is suggested that the formation of Co Mo S improves the activity toward alcohol. Additionally, it is found that the sample prepared by sol gel method and treated in argon atmosphere has the smallest size of MoS 2 crystallites, while the Co 9S 8 shows no notable change.