The role of sodium surface species on electrochemical promotion of catalysis in a Pt/YSZ system: The case of ethylene oxidation
The role of sodium surface species on electrochemical promotion of catalysis in a Pt/YSZ system: The case of ethylene oxidation
复制标题
DOI：
10.1016/j.jcat.2013.03.015
复制
发表时间：
2013-07
影响因子：
7.3
通讯作者：
N. Ibrahim;D. Poulidi;I. Metcalfe
中科院分区：
文献类型：
--
作者：
N. Ibrahim;D. Poulidi;I. Metcalfe
研究了在铂/YSZ体系中，钠作为杂质物种对乙烯氧化的电化学促进作用。研究发现，催化剂表面的钠物种可以显著影响其催化和电催化性能，但目前还没有明确的证据表明这种物种是观察EPOC所必需的。在负极化下，低覆盖度的钠作为电子促进剂对乙烯氧化有显著的电化学促进作用。该反应从低钠覆盖率(0.11%)和中低氧分压(pO2⩽3.0kPa)下的亲电性转变为高钠覆盖率(65%)和高氧分压(pO2=8.0kPa)下的电泳性。在这两组条件之间，反应表现出火山类型的行为，这取决于钠和气相氧气分压的覆盖率。
The role of sodium addition as foreign (impurity) species on the electrochemical promotion of ethylene oxidation in a Pt/YSZ system was investigated. It was found that the presence of sodium surface species on the catalyst surface can significantly affect its catalytic and electrocatalytic properties, but there is no clear evidence at this stage that such species are necessary for the observation of EPOC. Under negative polarisation, low coverage sodium was found to have a pronounced effect on the electrochemical promotion of ethylene oxidation as an electronic promoter. The reaction changed behaviour from electrophilic at low sodium coverage (0.11%) and low to intermediate oxygen partial pressure (pO2⩽3.0kPa) to electrophobic at high sodium coverage (65%) and under high oxygen partial pressures (pO2=8.0kPa). In between the two sets of conditions, the reaction showed volcano-type behaviour depending on the coverage of sodium and gas-phase oxygen partial pressure.