磷化镍/介孔TiO_2催化剂的制备及其催化加氢脱硫性能

Preparation of Nickel Phosphide/Mesoporous-TiO_2 Catalyst and Its Hydrodesulfurization Performance

以介孔TiO2(m-TiO2)为载体,采用程序升温还原法制备了Ni2P/m-TiO2催化剂,考察了不同起始Ni/P摩尔比及活性组分负载量对该催化剂结构及其催化加氢脱硫(HDS)性能的影响.结果表明,当Ni/P摩尔比为1.25时,活性组分以Ni2P为主,催化剂的最佳Ni负载量为10%.采用X射线衍射、低温N2吸附-脱附、场发射扫描电镜和程序升温还原等技术表征了m-TiO2及其它不同载体负载的Ni2P催化剂.结果表明,高结晶度m-TiO2载体使Ni和P物种的还原温度大幅度降低,在450～600oC还原制得的Ni2P/m-TiO2催化剂的结构参数基本一致,比表面积均为90m2/g左右,具有很高的热稳定性和对二苯并噻吩的HDS催化性能.在相同的反应条件下,m-TiO2负载的Ni2P催化剂HDS性能最好,各载体负载的Ni2P催化剂活性大小顺序为Ni2P/m-TiO2>Ni2P/SiO2>Ni2P/P25.

Using mesoporous TiO2 （m-TiO2） as the support, novel nickel phosphide/m-TiO2 catalysts （Ni2P/m-TiO2） were prepared by a temperature-programmed reduction method. The influence of the Ni/P molar ratio and the amount of active component on the catalyst structure and the hydrodesulfurization （HDS） performance was investigated. The results indicated that the reduction of precursor with Ni/P = 1.25 yielded mainly Ni2P, and the optimum loading of Ni was 10%. The influence of m-TiO2 on the preparation and HDS performance of nickel phosphide catalysts was also evaluated by X-ray diffraction, N2 physisorption, field-emission scanning electron microscopy, and temperature-programmed reduction. The results showed that m-TiO2 with high crystallinity could dramatically decrease the reduction temperatures of Ni and P species. When the reduction temperatures were between 450 and 600 °C, the textures of the Ni2P/m-TiO2 catalysts were very similar and the specific surface areas were about 90 m2/g. The effects of the support on the dibenzothiophene HDS performance of the nickel phosphide catalysts were also investigated. The results showed that the order of dibenzothiophene conversion was Ni2P/m-TiO2 Ni2P/SiO2 Ni2P/P25.