ACTIVATION OF NITROGEN BY ALKALI-METAL PROMOTED TRANSITION-METAL .1. AMMONIA SYNTHESIS OVER RUTHENIUM PROMOTED BY ALKALI-METAL
ACTIVATION OF NITROGEN BY ALKALI-METAL PROMOTED TRANSITION-METAL .1. AMMONIA SYNTHESIS OVER RUTHENIUM PROMOTED BY ALKALI-METAL
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DOI：
10.1016/0021-9517(72)90179-0
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发表时间：
1972-01-01
影响因子：
7.3
通讯作者：
HORI, H
中科院分区：
文献类型：
--
作者：
AIKA, K;OZAKI, A;HORI, H
发现添加碱金属可显着提高氨合成率相对于钌的合成率，特别是当钌由活性炭（AC）或氧化铝负载时。 5%RuACK催化剂在250℃时的合成率可提高至传统双促进铁(FeAl2O3K2O)催化剂的10倍左右。 RuACCs 比 RuACK 具有更高的活性。催化活性随着添加碱的电离势的降低（Cs>K>Na）和碱金属添加量的增加而增加，在大约3-4毫克原子碱/克催化剂处接近稳定值。添加碱金属也可显着促进无负载钌的生长。因此得出结论，促进作用是通过从碱金属到过渡金属的电荷转移提供的，这在过渡金属中带来更高的电子密度，这是有利于氮活化的状态。每个表面钌的具体合成率比活性炭和氧化铝高于其他载体，表明这些载体作为电子转移介质的作用。
The rate of ammonia synthesis over ruthenium was found to be remarkably promoted by addition of alkali metal, particularly when ruthenium is supported by active carbon (AC) or alumina. The synthesis rate over the 5% RuACK catalyst can be raised to about 10 times that of conventional doubly promoted iron (Fe Al2O3K2O) catalyst at 250 °C. RuACCs gives even greater activity than RuACK. The catalytic activity increases with decrease in ionization potential of added alkali (Cs > K > Na) and with increase in the added amount of alkali metal, approaching a plateau value at around 3–4 mg-atom alkali/g-catalyst. Unsupported ruthenium is also remarkably promoted by addition of alkali metal. It is accordingly concluded that the promoter action is provided by a charge transfer from alkali metal to transition metal which brings about a higher electron density in the transition metal, a favorable state for the activation of nitrogen. The specific synthesis rates per surface ruthenium are higher over active carbon and alumina than other supports, suggesting a role of these supports as a medium of electron transfer.