稀土和过渡金属助剂对氧化脱硫催化剂反应性能影响

The Effect of Rare Earths and Transition Metals Additives on Catalytic Oxidative Desulfurization

采用溶胶-凝胶法制备了不同稀土金属和过渡金属离子为助催化剂的SiO_2负载型磷钼酸(HPMo)催化剂M-HPMo/SiO_2(M=Eu、La、Ni、Co),研究了此催化剂在模拟柴油的催化氧化脱硫反应中的性能。使用X射线衍射(XRD)、傅里叶变换-红外光谱FT-IR、N2吸附-脱附等分析手段对催化剂的结构进行了表征。结果表明,稀土金属和过渡金属离子的加入保持了磷钼酸的Keggin结构,并促进了磷钼酸活性中心在SiO_2表面的分布,稀土元素催化助剂Eu在反应中的助催化作用最为明显,Eu-HPMo/SiO_2有较高的催化活性。在催化剂用量为0.1 g、反应温度为50℃、n(H_2O_2)/n(S)=3、反应时间60 min,催化剂Eu-HPMo/SiO_2对DBT的脱除率为99.2%。该脱硫反应为表观一级反应,反应表观活化能为51.16±5.79 k J/mol,指前因子A=6154±697。

M-HPMo / SiO2（M = Eu、Ni、La、Co） catalysts were prepared by the sol- gel method. The catalysts were characterized by X- ray diffraction（ XRD）,FT- IR and nitrogen adsorption- desorption isotherm. The catalysts performance were evaluated by catalytic oxidative dusulfurizaion for the simulated diesel oil. The result shows that rare earth and transition metal ions promotes the distribution of phosphomolybdic acid on the surface of the catalyst. At the conditions of catalyst 0. 1 g,n（ H2O2） /n（S） = 3 and reaction temperature 50 ℃,99. 2% dibenzothiophene removal was observed over Eu-HPMo/SiO2.The oxidative desulfurization reaction is the pseudo first- order reaction and the apparent activation energy is found to be51. 16 ± 5. 79 k J / mol.