采用低温燃烧法和溶剂热法分别合成了富含五配位Al³⁺物种的氧化铈改性Al₂O₃(Ce-Al₂O₃)和介孔-大孔Al₂O₃(M-Al₂O₃);通过程序升温还原浸渍法负载的Mo的磷酸盐前驱体制备了MoP催化剂。以二苯并噻吩(DBT)为模型含硫化合物评价了其加氢脱硫(HDS)性能。结果表明,M-Al₂O₃上制备纯相MoP所需磷酸盐前驱体的P/Mo摩尔比在1~1.2之间。DBT在MoP催化剂上转化率大小为MoP(1)/SiO₂>MoP(1)/Ce-Al₂O₃>MoP(1.2)/M-Al₂O₃。动力学研究表明,DBT在MoP(1)/Ce-Al₂O₃和MoP(1.2)/M-Al₂O₃上的HDS反应活化能几乎相同,显著小于MoP(1)/SiO₂上的活化能。在MoP催化剂上,直接脱硫(DDS)路径选择性随温度的增加而增加。在较低的温度下(如280℃),DBT主要通过加氢(HYD)反应路径脱硫;在较高的温度下(如360℃),DDS和HYD两条反应路径并重。

A cerium oxide modified Al₂O₃ (Ce-Al₂O₃) and a macro-mesoporous Al₂O₃ (M-Al₂O₃),which are both rich in pentahedrally coordinated Al³⁺,are synthesized via a low-temperature combustion method and a solvothermal method,respectively.MoP catalysts are obtained through temperature-programmed method to reduce the supported molybdenum phosphate precursors prepared via an impregnation method.The hydrodesulfurization performances of MoP catalysts are evaluated through using dibenzothiophene (DBT) as model sulfur-containing compound.It is indicated that the P/Mo molar ratio in the phosphate precursor required for the formation of phase-pure MoP over M-Al₂O₃ is between 1 and 1.2.The conversion of DBT over MoP catalysts drops in the order of MoP(1)/SiO₂>MoP(1)/Ce-Al₂O₃>MoP(1.2)/M-Al₂O₃.It is demonstrated by the kinetic study that the hydrodesulfurization activation energy of DBT over MoP(1)/Ce-Al₂O₃ is nearly same as that over MoP(1.2)/M-Al₂O₃,both are much lower than that over MoP(1)/SiO₂.Over these MoP catalysts,the selectivity of the direct desulfurization pathway increases with the rising temperature.At a relatively low temperature (e.g.280℃),the desulfurization of DBT occurs mainly through the hydrogenation pathway;while at a high temperature (e.g.360℃),both the direct desulfurization and hydrodesulfurization pathways play an equal role.

邹洁(1985-),女,本科,副教授,研究方向为加氢精制及电催化析氢,55831883@qq.com