The genesis of the active phase in Raney-type catalysts: the role of leaching parameters
The genesis of the active phase in Raney-type catalysts: the role of leaching parameters
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DOI：
10.1016/s0926-860x(02)00601-4
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发表时间：
2003-05
影响因子：
5.5
通讯作者：
F. Devred;B. Hoffer;W. Sloof;P. Kooyman;A. D. Langeveld;H. Zandbergen
中科院分区：
文献类型：
--
作者：
F. Devred;B. Hoffer;W. Sloof;P. Kooyman;A. D. Langeveld;H. Zandbergen
本文研究了两种工业用50- 50 wt.%研究了镍铝合金（A和B）。正如相图所预期的那样，观察到NiAl 3、Ni 2Al 3和少量金属铝。两个主相的分布由Ni 2Al 3的核和NiAl 3的壳组成。即使起始合金的组成相同，不同相的量也不同：在合金B中存在更多的Ni 2Al 3和更少的金属铝。用氢氧化钠水溶液处理（浸提过程）得到阮内型镍催化剂。使用不同的浸出时间，以遵循催化剂的形态的演变。活化过程非常快，在10秒的浸出后，大部分铝已经浸出并以氧化铝形式存在。浸出时间越长，催化剂的催化性能（活性和选择性）越好。在由合金A制成的催化剂的情况下，催化性能随时间的变化更加明显。
The morphology and microstructure of two commercial 50–50wt.% nickel aluminium alloys (A and B) have been studied. As expected from the phase diagram, NiAl3, Ni2Al3and a small amount of metallic aluminium were observed. The distribution of the two main phases consists of a core of Ni2Al3with a shell of NiAl3. Even if the composition of the starting alloys was the same, the amounts of the different phases are different: more Ni2Al3and less metallic aluminium were present in alloy B. Treatment with an aqueous sodium hydroxide solution (leaching process) leads to Raney-type nickel catalyst. Different leaching times were used in order to follow an evolution in the morphology of the catalysts. The activation process is very fast and after 10s of leaching, most of the aluminium has been leached out and is present as alumina. The longer the leaching time, the better the catalytic performance (both activity and selectivity) of the catalysts. This evolution of catalytic performance as function of time is much more pronounced in the case of catalysts issued from alloy A.