Currently, platinum is the most widely used catalyst for low temperature proton exchange membrane fuel cells (PEMFC). However, the kinetics at the cathode are slow, and the price of platinum is high. To improve oxygen reduction reaction (ORR) kinetics at the cathode, platinum can be alloyed with rare earth elements, such as yttrium. We report that Pt3Y has the potential to be over 2 times more active for the ORR compared with Pt inside a real fuel cell. We present detailed photoemission analysis into the nature of the sputtered catalyst surface, using synchrotron radiation photoelectron spectroscopy (SRPES) to examine if surface adsorbates or impurities are present and can be removed. Pretreatment removes most of the yttrium oxide in the surface leaving behind a Pt overlayer which is only a few monolayers thick. Evidence of a substochiometric oxide peak in the Y 3d core level is presented, this oxide extends into the surface even after Ar+ sputter cleaning in-situ. This information will aid the development of new highly active nanocatalysts for employment in real fuel cell electrodes.

中文翻译：

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用于低温燃料电池的高活性 Pt 3 Y 合金催化剂的表面组成

目前，铂是低温质子交换膜燃料电池（PEMFC）使用最广泛的催化剂。然而，阴极的动力学很慢，铂的价格很高。为了改善阴极的氧还原反应 (ORR) 动力学，铂可以与稀土元素（例如钇）形成合金。我们报告说，与实际燃料电池内的 Pt 相比，Pt3Y 的 ORR 活性有可能高出 2 倍以上。我们对溅射催化剂表面的性质进行了详细的光电发射分析，使用同步辐射光电子能谱 (SRPES) 来检查表面吸附物或杂质是否存在并且可以去除。预处理去除了表面的大部分氧化钇，留下只有几个单层厚的 Pt 覆盖层。提供了 Y 3d 核心级中亚化学计量氧化物峰的证据，即使在原位 Ar+ 溅射清洁后，该氧化物也会延伸到表面。该信息将有助于开发用于实际燃料电池电极的新型高活性纳米催化剂。