免焙烧制备Ni2P/SiO2加氢脱硫催化剂

Preparation of Ni_2P/SiO_2 Hydrodesulfurization Catalyst by a Non-Calcination Method

采用免焙烧的方法,直接将负载Ni（NO3）2和（NH4）2HPO4盐的前驱体通过程序升温还原（TPR）制备了Ni2P/SiO2加氢脱硫（HDS）催化剂.以质量分数为0.8％的二苯并噻吩/十氢萘溶液为模型化合物,考察了Ni2P/SiO2催化剂的HDS反应催化性能,并用XRD对催化剂进行了表征.结果表明,免焙烧法制备的Ni2P/SiO2催化剂的单层分散阈值在15％～25％（质量分数）之间.随负载量增加,Ni2P/SiO2催化剂的HDS活性增加,但直接脱硫路径（DDS）选择性降低;当活性组分负载量大于单层分散阈值时,继续增加负载量对催化剂粒度和反应性能影响不大.免焙烧法制备的Ni2P/SiO2催化剂的HDS活性与传统方法制备的催化剂相当（负载量大于单层分散阈值时）或更高（负载量小于单层分散阈值时）,并且具有良好的反应稳定性.TPR过程中升温程序是影响免焙烧法制备的Ni2P/SiO2催化剂HDS性能的重要因素;低温阶段升温速率对催化剂性能没有明显影响,而在400℃停留一段时间则有利于提高其活性.

Ni2P/SiO2 hydrodesulfurization （HDS） catalysts were prepared by a non-calcination method,in which the precursors containing Ni（NO3）2 and （NH4）2HPO4 were directly converted to the active phosphide phase through the temperature-programmed reduction （TPR） procedure.The HDS performances of the prepared Ni2P/SiO2 catalysts were studied with a model fuel containing 0.8％ （mass fraction） dibenzothiophene in decalin,and the morphologies of the catalysts were characterized by XRD.The results indicated that the monolayer dispersion threshold of the Ni2P/ SiO2 catalysts prepared by the non-calcination method was between 15 ％-25 ％ （mass fraction）.The increase of the active component loading in Ni2P/SiO2 catalyst led to the increase of HDS activity and the decrease of the direct desulfurization pathway selectivity.However,further increase in the active component loading would not affect the particle sizes and HDS activity of the catalyst,when the loading was above the monolayer dispersion threshold.The catalyst prepared by the non-calcination method exhibited a good stability during HDS reaction,and its HDS activity was equal to （when the loading was above the monolayer dispersion threshold） or higher than （when the loading was less than the monolayer dispersion threshold） that of the catalyst prepared by conventional method.The heating program in the TPR method was a key parameter affecting the HDS activity of Ni2P/SiO2.The heating rate at lower temperature region hardly affected the HDS performance of the catalyst,while holding at 400℃ for a short period had a positive action to its HDS activity.