Mo-Ni2P/SBA-15催化剂的制备、表征及加氢脱硫催化性能

以介孔分子筛SBA-15 为载体, 通过分步浸渍硝酸镍、磷酸氢二铵、钼酸铵, 然后在H₂气流下程序升温还原(H₂-TPR), 制备了一系列不同Mo 含量的Mo-Ni₂P/SBA-15 催化剂. 采用X 射线衍射(XRD)、氮气吸脱附(BET)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)对催化剂的结构进行了表征, 评价了催化剂对二苯并噻吩(DBT)的加氢脱硫(HDS)活性. 结果表明, Mo-Ni₂P/SBA-15 催化剂仍然保留有介孔结构, 催化剂的物相主要是Ni₂P. 催化剂表面的Ni 以Ni^δ+和Ni²⁺形式存在; P以P^δ-和P⁵⁺形式存在; Mo以Mo^δ+和Mo⁶⁺形式存在. Mo能促进催化性能的提高, 其中Mo含量为1% (w, 质量分数)的Mo-Ni₂P/SBA-15 催化剂具有最好的二苯并噻吩加氢脱硫催化活性, 在反应温度为380 ℃, 反应压力为3.0 MPa的条件下, 二苯并噻吩的转化率可达99.03%, 所有考察的Mo-Ni₂P/SBA-15都以直接加氢脱硫(DDS)途径为主.

Preparation,Characterization and Hydrodesulfurization Catalytic Performances of Mo-Ni2P/SBA-15 Catalysts

A series of Mo-Ni₂P/SBA-15 catalysts with various Mo loadings were prepared by impregnating nickel nitrate, diammonium hydrogen phosphate, and ammonium molybdate onto an SBA-15 support, followed by temperature-programmed reduction (TPR) under H₂. The structure of the catalysts was characterized by Xray diffraction (XRD), N₂ adsorption-desorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic performance was evaluated in the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The results indicate that the mesoporous structure was maintained and the Ni₂P phase was present in all of the catalysts. The chemical states of Ni were Ni^δ+ and Ni²⁺, the chemical states of P were P^δ- and P⁵⁺, and the chemical states of Mo were Mo^δ+ and Mo⁶⁺. Mo was shown to promote the HDS catalytic performance of Ni₂P/SBA-15 catalysts. The Mo-Ni₂P/SBA-15 catalysts with 1% (w, mass fraction) Mo loading exhibited the highest HDS activity. The conversion of the DBT reached 99.03%under reaction conditions of 380 ℃ and 3.0 MPa. The HDS of DBT proceeded mainly via the direct desulfurization (DDS) pathway over all of the tested Mo-Ni₂P/SBA-15 catalysts.