论文部分内容阅读
利用ＸＲＤ，ＳＥＭ 和Ｒａｍａｎ 光谱等手段对ＮａＷＭｎ／ＳｉＯ２ 催化剂中形成的物相、活性组分在载体表面的分散度以及催化剂表面的金属中心结构进行了研究． 结果表明，组分间的相互作用对各活性组分在催化剂中的存在形式有重要影响． 在无定形氧化硅表面， Ｗ 以八面体六配位ＷＯ３ 形式存在，在α方石英表面， Ｗ 以四面体四配位的ＷＯ４ 形式存在． 没有组分Ｎａ 时， Ｗ 或Ｍｎ 在催化剂表面以氧化物颗粒形式存在； Ｎａ 的加入不仅可大大提高Ｗ或Ｍｎ 在催化剂表面的分散度，而且可使ＷＯ４ 四面体的结构变得十分均一． 反应性能研究还表明， Ｎａ 和Ｍｎ 之间存在很强的电子相互作用，对于含Ｍｎ 催化剂的选择性具有重要影响．
The phase formed on the NaWMn / SiO2 catalyst, the dispersity of the active component on the support surface and the metal center structure on the catalyst surface were studied by means of XRD, SEM and Raman spectroscopy. The results show that the interaction between the components of the active components in the presence of catalyst has a significant impact. On the surface of amorphous silica, W exists in the form of octahedral hexahedral WO3, and exists on the surface of α-cristobalite as tetrahedral tetrahedral WO4. In the absence of component Na, W or Mn exists as oxide particles on the surface of the catalyst. The addition of Na not only greatly improves the dispersibility of W or Mn on the catalyst surface, but also makes the structure of WO4 tetrahedron to be very uniform. The study of the reaction performance also shows that there is a strong electronic interaction between Na and Mn, which has an important influence on the selectivity of Mn-containing catalysts.