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应用激光喇曼光谱研究了Mo/TiO_2(Anatase)催化剂表面Mo的化学形态和制备条件的关系,并和Mo/γ-Al_2O_3进行了比较。钼在两种载体上的化学形态基本相似,没有发现新物相。在相同条件下,钼在TiO_2(A)上生成的聚钼酸的端基Mo=O的喇曼散射频率比在γ-Al_2O_3上向较高波数方向移动,这意味着钼酸的聚合度更高一些。一般认为催化剂表面上聚钼酸是催化活性相,钼酸聚合度越高,催化剂的加氢脱氮活性也高。聚集态的MoO_3则是非活性相,MoO_3浓度随钼浓度的增加而增加,所以TiO_2(A)上钼的担载量对催化剂活性的贡献是有一定限度的。
The relationship between the chemical species of Mo on the surface of Mo / TiO 2 (Anatase) catalyst and its preparation conditions was studied by laser Raman spectroscopy and compared with Mo / γ-Al 2 O 3. The chemical forms of molybdenum on the two carriers were similar and no new phase was found. Under the same conditions, the Raman scattering frequency of Mo = O, which is the terminal of molybdic acid generated by molybdenum on TiO_2 (A), is shifted higher than that of γ-Al_2O_3, which means that the degree of polymerization of molybdic acid is more Higher. It is generally believed that the polymolybdic acid is a catalytically active phase on the catalyst surface. The higher the degree of polymerization of molybdic acid, the higher the hydrodenitrogenation activity of the catalyst. Aggregate MoO_3 is inactive phase, MoO_3 concentration increases with the increase of molybdenum concentration, so the amount of molybdenum on TiO_2 (A) contribution to the catalyst activity has a certain limit.