添加金属对MoO3/Al2O3 碳化过程的影响

通过对镍、铜和钾改性的MoO3/Al2 O3样品进行与甲烷的程序升温表面反应 (CH4 TPSR)研究以及其碳化样品的BET测定 ,发现镍的添加对于甲烷还原以及碳化氧化钼具有促进作用 ,并对甲烷在碳氧化物或碳化物表面上的活化也具有促进作用 ,镍改性的碳化物样品具有较大的比表面和对甲烷比较高的本征活性 ;铜的添加对于甲烷还原以及碳化氧化钼稍有促进作用 ,对于甲烷在碳氧化物或碳化物表面上的活化稍有促进作用 ,但铜的引入也会加快催化剂的烧结 ;钾的添加对氧化钼被甲烷的还原以及碳化都不利 ,对于甲烷的活化也不利 ,钾的加入还会促使催化剂烧结 .因此 ,钾的添加对于甲烷在碳氧化物或碳化物上的转化是不利的

Effects of Doping Metal on the Carburization of MoO3/Al2O3

The investigation on MoO 3/Al 2O 3 sample or its modifiers with nickel, copper or potassium was performed using temperature programmed surface reaction (TPSR) technique and measurements of BET surface area. The results indicate that addition of nickel promotes the methane reduction, further the carburization, of MoO 3, and addition of nickel also promotes the activation of methane over the surface of oxycarbide or carbide due to the increase of active sites per unit area and intrinsic activity of catalytic centers. This is favorable to the conversion of methane. The addition of copper promotes the methane reduction, further the carburization, of MoO 3 to some extent, while the introduction of copper also accelerates the sintering of catalyst to a degree. Thus copper doped carbide catalyst exhibits its exceptionally catalytic performance. However, potassium prevents the MoO 3 from reduction with methane, which is unfavorable to the carburization. Potassium also restrains methane from being activated over the surface of oxycarbide or carbide. MoO 3/Al 2O 3 doped with potassium is of lower specific area, which originates from its boosting sintering of catalyst. This caauses the inferior methane conversion over potassium doped carbide catalyst.