Pd-based electrocatalysts are considered to be a promising alternative to Pt in anion-exchange membrane fuel cells (AEMFCs), although major challenges remain. Most of the Pd-based electrocatalysts developed for the sluggish oxygen reduction reaction (ORR) have been exclusively evaluated by rotating disk electrode (RDE) voltammetry at room temperature, rather than in membrane electrode assemblies (MEAs), making it challenging to apply them in practical fuel cells. We have developed a series of carbon-supported novel PdH_x nanosheets (PdH_x NS), which displayed outstanding ORR performance in room-temperature RDE tests. Specifically, a sample synthesized at 190 °C displayed a mass activity of 0.67 A mg^–1 and a specific activity of 1.07 mA cm^–2 at 0.95 V vs RHE, representing the highest reported value among Pd-based ORR electrocatalysts in alkaline media and higher than Pt-based catalysts reported in the literature. Furthermore, we employed PdH_x NS and commercial Pd/C as model catalysts to systematically study the effects of temperature on their ORR activity in RDE measurements and subsequently evaluated their performance in MEA testing. Our observations indicate/demonstrate how oxidative stability affected the ORR performance of Pd-based electrocatalysts, which provided some critical insights into future ORR catalyst development for alkaline fuel cell applications.

中文翻译：

---

氧化稳定性很重要：用于碱性燃料电池的氢化钯纳米片的案例研究

尽管仍存在重大挑战，但基于 Pd 的电催化剂被认为是阴离子交换膜燃料电池 (AEMFC) 中 Pt 的有前途的替代品。大多数为缓慢氧还原反应 (ORR) 开发的 Pd 基电催化剂仅在室温下通过旋转圆盘电极 (RDE) 伏安法进行评估，而不是在膜电极组件 (MEA) 中进行评估，因此很难将它们应用于实用的燃料电池。我们开发了一系列碳负载的新型 PdH _x纳米片 (PdH _x NS)，在室温 RDE 测试中表现出出色的 ORR 性能。具体来说，在 190 °C 合成的样品显示出 0.67 A mg ^–1的质量活度和 1.07 mA cm ^{–2的比活度}在 0.95 V vs RHE，代表了 Pd 基 ORR 电催化剂在碱性介质中的最高报道值，高于文献中报道的 Pt 基催化剂。此外，我们采用 PdH _x NS 和商业 Pd/C 作为模型催化剂，系统地研究了温度对其 RDE 测量中 ORR 活性的影响，并随后评估了它们在 MEA 测试中的性能。我们的观察表明/证明了氧化稳定性如何影响 Pd 基电催化剂的 ORR 性能，这为未来用于碱性燃料电池应用的 ORR 催化剂开发提供了一些重要的见解。