The combined promotional effect of electrochemically-supplied O2- and chemically-supplied Na+ promoters, was studied for the case of CO oxidation on Pt/YSZ. Four different sodium coverages (0.16, 1.6, 8 and 40%) were loaded onto the catalyst surface and the catalytic behaviour was compared with a nominally 'clean' catalyst under a wide range of reactants' ratios under open-circuit and polarised conditions. Sodium generally increased oxygen adsorption by lowering the work function of the catalyst. However, sodium promoted the catalytic rate only at coverages up to 1.6% and worked synergistically with O2- promoting species to an increased overall promotion of the catalytic rate. At higher sodium coverages, i.e. θNa ≥ 8%, the catalytic behaviour was strongly affected by the interactions between the sodium species, the catalyst, the reactants and oxygen ions promoting species. The postulated formation of stable sodium oxide species on the catalyst pores reduced the active catalytic area which resulted in poisoning the catalytic rate and suppressing EPOC effect, respectively. It is suggested that these stable sodium oxide species which also induced a permanent EPOC effect by oxygen storage, were formed by the migrated oxygen ions.

中文翻译：

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钠促进的Pt / YSZ上CO氧化的电化学促进：多种促进物种之间的相互作用。

对于在Pt / YSZ上进行CO氧化的情况，研究了电化学提供的O2-和化学提供的Na +促进剂的联合促进作用。将四种不同的钠覆盖率（0.16％，1.6％，8％和40％）加载到催化剂表面，并在开路和极化条件下，在各种反应物比率下，将催化性能与标称“清洁”催化剂进行比较。钠通常通过降低催化剂的功函数来增加氧的吸附。但是，钠仅在覆盖率高达1.6％时才促进催化速率，并且与促进O2的物种协同工作，从而提高了整体的催化速率。在较高的钠离子覆盖度（即θNa≥8％）下，钠离子，催化剂，反应物和氧离子促进物质。假定在催化剂孔上形成稳定的氧化钠物种会减少活性催化面积，从而分别导致催化速率中毒和抑制EPOC效应。提示这些稳定的氧化钠物质是通过迁移的氧离子形成的，它们也通过储氧引起永久的EPOC效应。