The electrochemical promotion of ethylene oxidation at a Pt/YSZ catalyst.
The electrochemical promotion of ethylene oxidation at a Pt/YSZ catalyst.
复制标题
Pt/YSZ 催化剂上电化学促进乙烯氧化。
作者：
Arafat Toghan;Liz M. Rösken;R. Imbihl
研究了在 10(-5) 和 10(-4) mbar 范围内，使用连接钇稳定氧化锆 (YSZ) 的 Pt 催化剂作为工作电极，电化学促进 C(2)H(4)+O(2) 反应形成 CO(2) 和 H(2)O。使用光电发射电子显微镜（PEEM）作为空间分辨方法。在开路条件下，即没有施加外部电压的情况下，CO(2) 的产生在 p(C(2)H(4)) 的循环变化时表现出明显的滞后现象。滞后现象归因于碳质 CH(x) 层的形成，抑制 O(2) 吸附，从而毒害反应。结果表明，施加 1 V 的正电位会触发反应从非反应分支到活跃分支的转变。文献中报道的该反应体系的大非法拉第度被解释为由于部分去除抑制性碳质层而引起的点火效应。
The electrochemical promotion of the C(2)H(4)+O(2) reaction to form CO(2) and H(2)O is studied in the 10(-5) and 10(-4) mbar range with a Pt catalyst interfaced as working electrode to yttrium-stabilized zirconia (YSZ). Photoemission electron microscopy (PEEM) was used as spatially resolving method. Under open-circuit conditions, that is, without an external voltage applied, the CO(2) production exhibits a pronounced hysteresis upon cyclic variation of p(C(2)H(4)). The hysteresis is attributed to the build-up of a carbonaceous CH(x) layer inhibiting O(2) adsorption and hence poisoning the reaction. It is shown that the application of a positive potential of 1 V triggers a transition from the unreactive branch of the reaction to an active branch. The large non-Faradayicity reported in the literature for this reaction system is explained as an ignition effect caused by the partial removal of the inhibiting carbonaceaous layer.