THE EFFECT OF ELECTROCHEMICAL OXYGEN PUMPING ON THE RATE AND SELECTIVITY OF ETHYLENE OXIDATION ON POLYCRYSTALLINE SILVER
THE EFFECT OF ELECTROCHEMICAL OXYGEN PUMPING ON THE RATE AND SELECTIVITY OF ETHYLENE OXIDATION ON POLYCRYSTALLINE SILVER
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DOI：
10.1016/0021-9517(81)90323-7
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发表时间：
1981-01-01
影响因子：
7.3
通讯作者：
VAYENAS, CG
中科院分区：
文献类型：
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作者：
STOUKIDES, M;VAYENAS, CG
电化学氧泵对多晶银上乙烯氧化的选择性和环氧乙烷产率有显著影响。在固体电解质电池C_2H_4，C_2H_4O，CO_2，O_2，Ag γ ZrO_2（Y_2O_3）γ Ag，空气中，在400 °C附近，常压下研究了反应。在开路条件下，暴露于乙烯-O2混合物的多孔银电极充当C2 H4、氧化成C2 H4 O和CO2的正常催化剂。结果发现，当电池外加电压，O2−被“泵入”催化剂时，环氧乙烷的选择性和产率显著增加。在电压极性反转时观察到相反的效果。C2 H4 O生成速率的增加可以超过O2−泵送速率的400倍，表明银催化剂的性质发生了显著变化。这种现象是可逆的，典型的弛豫时间为几分钟的量级。提出了一个简单的模型来解释这一新现象。
The selectivity and ethylene oxide yield of ethylene oxidation on polycrystalline silver can be affected significantly by electrochemical oxygen pumping. The reaction was studied in the solid electrolyte cell C2H4, C2H4O, CO2, O2, Ag¦ZrO2(Y2O3)¦Ag, air at temperatures near 400 °C and atmospheric pressure. Under open-circuit conditions the porous silver electrode exposed to the ethylene-O2mixture acts as a normal catalyst for C2H4, oxidation to C2H4O and CO2. It was found that when external voltages are applied to the cell and O2−is “pumped” to the catalyst, the ethylene oxide selectivity and yield increase considerably. The opposite effect is observed upon inversion of the voltage polarity. The increase in the rate of C2H4O production can exceed the rate of O2−pumping by a factor of 400, indicating a dramatic change in the properties of the silver catalyst. The phenomenon is reversible and typical relaxation times are of the order of a few minutes. A simple model is proposed in order to explain this new phenomenon.