制备方法及载体类型对Ni_2P/TiO_2催化剂加氢脱硫性能的影响

以两种类型的TiO2(锐钛矿anatase、晶须载体whiskers)为载体,分别采用程序升温还原(H2-TPR)法和溶剂热法制备Ni2P/TiO2催化剂,并用X射线衍射(XRD)、N2吸附比表面积(BET)测定、N2等温吸附脱附、CO吸附表征、X射线光电子能谱(XPS)技术、扫描电镜(SEM)对催化剂的结构和性质进行了表征。考察了不同的制备方法及不同类型TiO2载体对Ni2P/TiO2催化剂二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明,溶剂热法制备催化剂过程中,保持了TiO2晶体结构,抑制了TiPO4的形成,HDS活性高于H2-TPR法制备的催化剂;与锐钛矿TiO2为载体的催化剂相比,以晶须TiO2为载体的催化剂具有更优良的表面性质,能生成较多晶体颗粒粒径较小、分散性好的Ni2P活性相,具有更高的HDS活性。以晶须TiO2为载体,采用溶剂热法制备的Ni2P/TiO2催化剂,具有最好的加氢脱硫活性,在340℃、3.0MPa、氢油体积比为500、质量空速(WHSV)2.0h-1的条件下,二苯并噻吩转化率达到为98.2%。

Effect of preparation method and support type on hydrodesulfurization performance of Ni2 P/TiO2 catalyst

Nickel phosphide catalysts, supported on whiskers and anatase TiO₂, were prepared by temperature programmed reduction method and solvothermal method, respectively. The catalysts were characterized by X-ray diffraction (XRD), N₂-adsorption specific surface area measurements (BET), N₂ adsorption-desorption,CO adsorption, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (TEM). The effects of preparation method and support type on catalyst activity for dibenzothiophene (DBT) hydrodesulfurization (HDS) were studied. The result showed that the structures of the TiO₂ support remained unchanged, and the formation of TiPO₄ was suppressed in solvothermal method process, contributing to higher catalytic activity of Ni₂P/TiO₂ catalysts for HDS than the catalysts obtained by conventional TPR method. Compared with the catalysts supported on anatase TiO₂, the catalysts supported on whiskers TiO₂ displayed excellent surface properties, producing more Ni₂P crystal particles with smaller size and better dispersion, and therefore possessed higher HDS activity. The HDS activity of the catalyst supported on whiskers TiO₂ and made by solvothermal method was found to be the best one among the tested catalysts. The conversion of dibenzothiophene HDS was 98.2% under the selected reaction conditions of 340 ℃, 3.0 MPa, H₂/oil ratio of 500 (volume ratio), and WHSV of 2.0 h^-1.