Synthesis and characterization of Pt-Co/C binary and Pt-Co-Ni/C ternary core-shell structured nanoparticle electrocatalysts for polymer electrolyte membrane fuel cells

聚合物电解质膜（PEM）燃料电池具有高功率密度、高能量转换效率和零排放等优点，被广泛认为是未来各种应用领域的动力装置。因此，在PEM燃料电池技术的开发中已经进行了广泛的努力。然而，PEM燃料电池继续面临主要由燃料电池材料和组件决定的成本和耐久性挑战。其中最重要的是催化氧还原反应（ORR）的阴极电催化剂。碳载铂（Pt）作为阴极电催化剂已被广泛应用于质子交换膜燃料电池中。然而，Pt的高成本使得阴极电催化剂成为导致燃料电池高成本的最重要因素。开发更有效的ORR催化剂以减少Pt的用量或取代昂贵的Pt一直是许多燃料电池研究人员的焦点。近年来，铂基合金被报道具有固有的增强铂催化剂的电催化活性的ORR，这可以潜在地减少铂的用量，提高燃料电池的性能。然而，在苛刻的燃料电池操作环境下，存在从Pt合金溶解的非贵金属的中毒效应，并且据报道该效应导致耐久性问题。据报道，这种效应会导致耐久性问题。在这项工作中，我们提出了使用三种方法来合成核壳结构的纳米粒子电催化剂在质子交换膜燃料电池中的应用。核-壳结构的催化剂具有非贵金属/金属合金核和Pt皮。这种核壳结构的催化剂将显著提高Pt的利用率，由于更有利的横向应变，有效地防止了非贵金属的析出，从而提高了Pt的本征活性。我们计划首先使用各种合成方法系统地研究二元和三元核-壳结构催化剂的合成过程，目标是开发可靠且具有成本效益的工艺，然后使用优化的合成路线研究放大效果，至少达到20 g/批次水平。所提出的工作预计将导致一个实际的工业合成过程，以生产高活性的核壳结构的催化剂的PEM燃料电池在显着低成本。

Due to its high power density, high energy conversion efficiency and zero emission, polymer electrolyte membrane (PEM) fuel cell has been widely considered to be the future power devices for many different types of applications. As a result, extensive efforts have been made in the development of PEM fuel cell technology. Nevertheless, PEM fuel cells continue to face cost and durability challenges that are predominately determined by the fuel cell materials and components. Paramount among them is the cathode electrocatalyst that catalyzes the oxygen reduction reaction (ORR). Platinum (Pt) supported on carbon has been commonly used in the PEM fuel cells as the cathode electrocatalyst. However, the high cost of Pt makes the cathode electrocatalyst the most significant factor that is responsible for the high cost of fuel cells. Development of more efficient ORR catalysts to reduce the dosage of Pt or replace the expensive Pt has been the focus of many fuel cell researchers. In recent years, Pt-based alloys have been reported to have intrinsic enhancement of the electrocatalytic activity of Pt catalysts for ORR, which can potentially reduce the Pt dosage and improve the fuel cell performance. However, there is a poisoning effect of the non-precious metals dissolved from the Pt alloy under the harsh fuel cell operation environment, and this effect has been reported to cause durability issues. This effect has been reported to cause durability issues. In this work, we propose to use three approaches to synthesize core-shell structured nanoparticle electrocatalysts for applications in PEM fuel cells. The core-shell structured catalysts have a non-precious metal/metal alloy core and a Pt skin. This core-shell structured catalyst will significantly improve the utilization of Pt, enhance the intrinsic activity of Pt due to more favorable lateral strain which effectively prevents the leach-out of the non-precious metal. We plan first to systematically investigate the synthesis procedures of binary and ternary core-shell structured catalysts using various synthesis methods with the goal of developing a reliable and cost-effective process and then study the scale-up effect with an optimized synthesis route to at least 20 g/batch level. The proposed work is expected to lead to a practical industrial synthesis process to produce highly active core-shell structured catalysts for PEM fuel cells at a significantly low cost.