An artifact appearing during the cathodic transient of cyclic voltammograms (CVs) of low-loaded platinum on carbon (Pt/C) electrodes in proton exchange membrane fuel cells (PEMFCs) was examined. The artifact appears as an oxidation peak overlapping the reduction peak associated to the reduction of platinum oxide (PtOx). By varying the nitrogen (N₂) purge in the working electrode (WE), gas pressures in working and counter electrode, upper potential limits and scan rates of the CVs, the artifact magnitude and potential window could be manipulated. From the results, the artifact is assigned to crossover hydrogen (H_2X) accumulating in the WE, once the electrode is passivated towards hydrogen oxidation reaction (HOR) due to PtOx coverage. During the cathodic CV transient, PtOx is reduced and HOR spontaneously occurs with the accumulated H_2X, resulting in the overlap of the PtOx reduction with the oxidation peak. This feature is expected to occur predominantly in CV analysis of low-loaded electrodes made of catalyst material, whose oxide is inactive towards HOR. Further, it is only measurable while the N₂ purge of the WE is switched off during the CV measurement. For higher loaded electrodes, the artifact is not observed as the electrocatalysts are not fully inactivated towards HOR due to incomplete oxide coverage, and/or the currents associated with the oxide reduction are much larger than the spontaneous HOR of accumulated H_2X. However, owing to the forecasted reduction in noble metal loadings of catalyst in PEMFCs, this artifact is expected to be observed more often in the future.

检查了质子交换膜燃料电池（PEMFC）中低负载铂/碳（Pt / C）电极的循环伏安图（CV）阴极瞬变期间出现的伪影。伪影表现为氧化峰，与氧化铂（PtOx）的还原相关的还原峰重叠。通过改变工作电极（WE）中的氮气（N ₂）吹扫，工作电极和对电极中的气压，CV的电势上限和扫描速率，可以控制伪影的大小和电势窗口。根据结果​​，将伪像分配给交叉氢（H _2X电极上由于PtOx覆盖而钝化成氢氧化反应（HOR）时，会在WE中累积）。在阴极CV瞬态过程中，PtOx还原，并且HOR自发地发生，并伴有H _2X累积，导致PtOx还原与氧化峰重叠。预期此功能主要发生在由催化剂材料制成的低负载电极的CV分析中，该电极材料的氧化物对HOR无活性。此外，只有在N ₂在CV测量期间，将关闭WE的吹扫。对于较高负载的电极，未观察到伪影，因为由于不完全的氧化物覆盖，电催化剂未完全向HOR失活，和/或与氧化物还原相关的电流远大于累积的H _2X的自发HOR 。但是，由于预测PEMFC中催化剂的贵金属负载量会减少，因此预计将来会更频繁地观察到这种假象。