Electrochemical Deposition for Electrochemical Energy Applications

质子交换膜燃料电池(PEMFC)具有能量效率高、功率密度高、启动快、工作温度低、连续工作、模块化、燃料灵活性和温室气体排放低等优点，是潜在的化石燃料的汽车和固定能源替代品。尽管有这些优点，质子交换膜燃料电池仍然面临着成本高和耐用性差的问题，这限制了它们的广泛使用。这些成本与它们对铂(铂)基电催化剂的依赖以及阴极催化剂层中需要较高的铂负载量来补偿氧还原反应(ORR)的缓慢动力学有关。 研究人员共同努力，通过使用铂与价格较低的过渡金属(如Co、Fe和Ni)合金化的电催化剂来降低铂的需求。这种方法不仅降低了材料成本，而且由于这些合金对ORR的活性高于纯铂，因此还被证明可以改善燃料电池的性能。然而，铂的负载量仍然远远高于美国能源部(DOE)设定的目标，这些铂合金催化剂的稳定性也存在问题。 这项研究的目的是应用电沉积技术来制备具有更高的ORR活性和稳定性的铂-钴催化剂薄膜，同时减少铂的负载量。尽管电沉积有一些优点并在过去取得了成功，但它在制备铂基催化剂方面并没有像其他方法那样被广泛使用。这项研究的目的是通过应用新的调制和脉冲技术来更充分地探索这些优势，这些技术提供了比直流电镀更多的操作变量来控制合金成分和沉积形貌。利用观察到的铂钴沉积行为，将开发一种新的、简单的方法来制备组成可调的催化薄膜，然后对其ORR活性和稳定性进行分析。如果成功，这可能会增加铂的利用率，足以将铂的负载量降低到DOE目标水平，并仍然能够改善ORR活性。

Proton exchange membrane fuel cells (PEMFC) are potential alternatives to fossil fuels as energy sources for automotive and stationary applications due to their high energy efficiency, high power density, quick start-up, low operating temperature, continuous operation, modularity, fuel flexibility and low greenhouse gas emissions. Despite these advantages, PEMFCs still face problems of high costs and less than desired durability that have limited their widespread use. These costs are linked to their reliance on platinum (Pt)-based electrocatalysts and the high Pt loading levels required in the cathode catalyst layer to compensate for the slow kinetics of the oxygen reduction reaction (ORR). Researchers have made concerted efforts to reduce the Pt requirement by using electrocatalysts consisting of Pt alloyed with less expensive transition metals such as Co, Fe and Ni. This approach not only reduces material costs, but also has been shown to improve fuel cell performance due to the higher activity of these alloys for the ORR than that of pure Pt. Nevertheless, the Pt loading is still much higher than the target set by the U.S. Department of Energy (DOE) and questions exist regarding the stability of these Pt alloy catalysts. The proposed research is aimed at applying electrodeposition techniques to fabricate Pt-Co catalyst films with improved ORR activity and stability, while reducing Pt loading. Electrodeposition is not as widely used to fabricate Pt-based catalysts as other methods although it has some advantages and has shown success in the past. The objective of the proposed research is to more fully explore these advantages by applying novel modulated and pulsed techniques that provide more operating variables to control alloy composition and deposit morphology than is possible with DC plating. A novel and simple method that takes advantage of the observed behaviour of Pt-Co deposition will be developed to fabricate catalyst films with tunable composition profiles which will then be analyzed for their ORR activity and stability. If successful, this could increase Pt utilization enough to lower Pt loading to the DOE target level and still be able to improve the ORR activity.