Abstract:

Pt-WO₃/α-Al₂O₃ catalysts were prepared with sequential impregnation of WO₃ and then Pt in α-Al₂O₃ supports without acid sites. The as-prepared were investigated the promotion of WO₃ catalysts in the reaction of hydrogenation of naphthene at mild reaction conditions. XRD, Raman, HRTEM, XPS, and H₂-TPR analyses reveal the basic structure and distribution of Pt and WO₃ species. Py-IR analyses reveal that the changing of acid sites after loading Pt and WO₃ species. Pt-WO₃/α-Al₂O₃ catalysts have shown excellent catalytic performance for the hydrogenation of naphthalene to decalin at mild reaction conditions (70℃, 3 MPa, 1 h) with the conversion and selectivity of decalin are 100%. Combined with the characterization and catalytic performance, the pre-introduced Pt and WO₃ species caused the strong interaction between Pd sites and WO₃ and the efficient distribution of Pt by WO₃ species. The strong acidity of the catalyst and the high degree of Pt dispersion are the key factors for the deep hydrogenation of naphthalene by Pt-WO₃/α-Al₂O₃ under low temperature conditions, which is of great significance for the process of decalin as a hydrogen storage medium.

Key words: naphthalene, decalin, support, tungsten oxide, hydrogenation, catalyst

摘要：

采用无酸性的α-Al₂O₃为载体，预先沉积WO₃然后浸渍法负载Pt物种，合成了系列Pt-WO₃/α-Al₂O₃催化剂用于萘深度加氢反应，系统地研究了氧化钨物种在萘加氢反应中的作用。通过XRD、Raman、HRTEM、XPS和H₂-TPR技术表征了Pt和WO₃物种在载体表面的分散情况和状态，并利用Py-IR研究了载体负载氧化钨和Pt前后的酸性质变化。在温和的反应条件下（70℃、3 MPa、1 h）Pt-WO₃/α-Al₂O₃催化剂表现出优异的萘深度加氢活性，萘的转化率和十氢萘的选择性均达到100%。结果表明，预先在载体表面引入的WO₃和Pt产生了强相互作用，WO₃提高了Pt物种的分散程度，催化剂的酸性来源于氧化钨物种的引入且和负载量成正比关系。催化剂较强的酸性和较高的Pt分散程度是Pt-WO₃/α-Al₂O₃在低温条件下能够使萘深度加氢的关键因素，对于十氢萘作为储氢介质工艺具有重要的意义。

关键词: 萘, 十氢萘, 载体, 氧化钨, 加氢, 催化剂