Achieving the optimal balance between cost-efficiency and stability of oxygen reduction reaction (ORR) catalysts is currently among the key research focuses aiming at reaching a broader implementation of proton-exchange membrane fuel cells (PEMFCs). To address this challenge, we combine two well-established strategies to enhance both activity and stability of platinum-based ORR catalysts. Specifically, we prepare ternary PtNi–Au alloys, where each alloying element plays a distinct role: Ni reduces costs and boosts ORR activity, while Au enhances stability. A systematic comparative analysis of the activity–stability relationship for compositionally tuned PtNi–Au model layers, prepared by magnetron co-sputtering, was conducted using a diverse range of complementary characterization techniques and electrochemistry, supported by density functional theory calculations. Our study reveals that a progressive increase of the Au concentration in the Pt₅₀Ni₅₀ alloy from 3 to 15 at % leads to opposing catalyst activity and stability trends. Specifically, we observe a decrease in the ORR activity accompanied by an increase in catalyst stability, manifested in the suppression of both Pt and Ni dissolution. Despite the reduced activity compared to PtNi, the PtNi–Au alloy with 15 at % Au still exhibits nearly three times the activity of monometallic Pt. It also demonstrates a significantly improved dissolution stability relative to that of the PtNi alloy and even monometallic Pt. These findings provide valuable insights into the intricate balance between activity and stability in multimetallic ORR catalysts, paving the way for the design of cost-effective and durable materials for PEMFCs.

中文翻译：

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通过三元 PtNi-Au 合金 ORR 催化剂的成分工程来平衡活性和稳定性


在氧还原反应 （ORR） 催化剂的成本效益和稳定性之间实现最佳平衡是目前旨在更广泛地实施质子交换膜燃料电池 （PEMFC） 的关键研究重点之一。为了应对这一挑战，我们结合了两种成熟的策略，以提高铂基 ORR 催化剂的活性和稳定性。具体来说，我们制备了三元 PtNi-Au 合金，其中每种合金元素都发挥着不同的作用：Ni 降低成本并提高 ORR 活性，而 Au 增强稳定性。在密度泛函理论计算的支持下，使用各种互补表征技术和电化学对由磁控管共溅射制备的成分调谐 PtNi-Au 模型层的活性-稳定性关系进行了系统的比较分析。我们的研究表明，Pt₅₀Ni₅₀ 合金中的 Au 浓度从 3% 逐渐增加到 15%，导致催化剂活性和稳定性趋势相反。具体来说，我们观察到 ORR 活性的降低伴随着催化剂稳定性的增加，表现在 Pt 和 Ni 溶解的抑制上。尽管与 PtNi 相比活性降低，但 Au 含量为 15% 的 PtNi-Au 合金的活性仍是单金属 Pt 的近三倍。与 PtNi 合金甚至单金属 Pt 相比，它还显示出显著提高的溶解稳定性。这些发现为多金属 ORR 催化剂的活性和稳定性之间的复杂平衡提供了宝贵的见解，为设计具有成本效益且耐用的 PEMFC 材料铺平了道路。