混合硝酸镍和醋酸镍制备的催化剂的特征和催化加氢抗硫性能

Catalytic Performances and Characterization of Ni/γ-Al_2O_3 from Ni(NO_3)_2-NiAc_2/γ-Al_2O_3

使用直接还原镍盐前体 [Ni(NO3 ) 2 /γ Al2 O3 ,NiAc2 /γ Al2 O3 或Ni(NO3 ) 2 NiAc2 /γ Al2 O3 ]和镍氧化物前体的方法制备催化剂 ,研究了它们的表面特征和甲苯加氢抗硫性能 .还原镍盐得到的催化剂比还原其焙烧成的氧化物制得的催化剂金属的还原和分散程度高 .Ni(NO3 ) 2 NiAc2 /γ Al2 O3 分解得到的氧化物前体的TPR在约 415℃出现了较小数量的块状NiO的还原峰 ;而Ni(NO3 ) 2 NiAc2 /γ Al2 O3 的TPR中镍盐分解成氧化物时的耗氢量变小 .用氢溢流的概念和镍盐分解时的耗氢量可以将TPR的结果和金属的分散性关联起来 .在镍盐前体催化剂上甲苯的加氢具有较高的活性 ,而两种盐摩尔比为 1∶1时 ,盐前体催化剂反应活性出现了一极大值 。

The catalysts prepared from reducing Ni(NO 3) 2/γ-Al 2O 3 and NiAc 2/γ-Al 2O 3 have higher metal dispersion than those from reducing the nickel oxide precursors. Reducing Ni(NO 3) 2-NiAc 2/γ-Al 2O 3 leads to lower metal dispersion than reducing Ni(NO 3) 2/γ-Al 2O 3 or NiAc 2/γ-Al 2O 3 does. But reducing the mixture of oxides prepared from Ni(NO 3) 2-NiAc 2/γ-Al 2O 3 leads to higher nickel dispersion than reducing the pure oxides. The TPR of the mixture of oxides presents small sharp peaks in bulk NiO reduction, but TPR of the mixture of salts consumes small amount of H 2 in the salt decomposition. Toluene hydrogenation rates of salt precursor catalysts are higher than that of oxide precursor catalysts. When two salts are mixed, a maximum of hydrogenation activity can be obtained for the salt precursor catalysts, meanwhile the highest sulfur resistance is obtained for both the salt and oxide precursor catalysts.