Heizmann Philipp A, Nguyen Hien, von Holst Miriam, Fischbach Andreas, Kostelec Mitja, Gonzalez Lopez Francisco Javier, Bele Marjan, Pavko Luka, Đukić Tina, Šala Martin, Ruiz-Zepeda Francisco, Klose Carolin, Gatalo Matija, Hodnik Nejc, Vierrath Severin, Breitwieser Matthias
Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany
Institute and FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg Georges-Köhler-Allee 105 79110 Freiburg Germany.
RSC Adv. 2023 Feb 6;13(7):4601-4611. doi: 10.1039/d2ra07780a. eCollection 2023 Jan 31.
The design of catalysts with stable and finely dispersed platinum or platinum alloy nanoparticles on the carbon support is key in controlling the performance of proton exchange membrane (PEM) fuel cells. In the present work, an intermetallic PtCo/C catalyst is synthesized double-passivation galvanic displacement. TEM and XRD confirm a significantly narrowed particle size distribution for the catalyst particles compared to commercial benchmark catalysts (Umicore PtCo/C). Only about 10% of the mass fraction of PtCo particles show a diameter larger than 8 nm, whereas this is up to or even more than 35% for the reference systems. This directly results in a considerable increase in electrochemically active surface area (96 m g >70 m g), which confirms the more efficient usage of precious catalyst metal in the novel catalyst. Single-cell tests validate this finding by improved PEM fuel cell performance. Reducing the cathode catalyst loading from 0.4 mg cm to 0.25 mg cm resulted in a power density drop at an application-relevant 0.7 V of only 4% for the novel catalyst, compared to the 10% and 20% for the commercial benchmarks reference catalysts.
在碳载体上设计具有稳定且高度分散的铂或铂合金纳米颗粒的催化剂是控制质子交换膜（PEM）燃料电池性能的关键。在本工作中，通过双钝化电置换法合成了一种金属间化合物PtCo/C催化剂。与商业基准催化剂（优美科PtCo/C）相比，透射电子显微镜（TEM）和X射线衍射（XRD）证实该催化剂颗粒的粒径分布显著变窄。只有约10%的PtCo颗粒质量分数显示直径大于8 nm，而参考体系中这一比例高达或甚至超过35%。这直接导致电化学活性表面积大幅增加（96 m²/g > 70 m²/g），这证实了新型催化剂中贵金属催化剂的使用效率更高。单电池测试通过改善PEM燃料电池性能验证了这一发现。将阴极催化剂负载量从0.4 mg/cm²降至0.25 mg/cm²时，对于新型催化剂，在与应用相关的0.7 V下功率密度下降仅为4%，而商业基准参考催化剂的这一数值分别为10%和20%。
