Highly Active and Stable Large Mo-Doped Pt-Ni Octahedral Catalysts for ORR: Synthesis, Post-treatments, and Electrochemical Performance and Stability.
Highly Active and Stable Large Mo-Doped Pt-Ni Octahedral Catalysts for ORR: Synthesis, Post-treatments, and Electrochemical Performance and Stability.
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DOI：
10.1021/acsami.2c02397
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发表时间：
2022-06
影响因子：
9.5
通讯作者：
Shlomi Polani;K. MacArthur;Jiaqi Kang;Malte Klingenhof;Xingli Wang;Tim Möller;Raffaele Amitrano;Raphaël Chattot;M. Heggen;R. Dunin‐Borkowski;P. Strasser
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文献类型：
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作者：
Shlomi Polani;K. MacArthur;Jiaqi Kang;Malte Klingenhof;Xingli Wang;Tim Möller;Raffaele Amitrano;Raphaël Chattot;M. Heggen;R. Dunin‐Borkowski;P. Strasser
在过去的十年中，用于燃料电池阴极的八面体形状的Pt-Ni合金纳米催化剂的胶体合成的进展已经提高了我们对颗粒形态和表面组成的原子尺度控制，这反过来又有助于提高其催化活性远远高于基准Pt催化剂。未来燃料电池在重型车辆中的部署导致科学优先级从合金颗粒活性转移到稳定性。较大的颗粒通常提供增强的热力学稳定性，但合成更大的八面体Pt-Ni合金纳米颗粒的方法仍然难以捉摸。在这项研究中，我们展示了如何一个简单的操作溶剂热合成反应动力学，涉及在反应的不同阶段的气相减压允许调整所得的八面体纳米催化剂的大小，以前未实现的规模。然后，我们将我们方法的潜在机制与经典的成核和生长“LaMer”模型联系起来。我们专注于大，退火钼掺杂Pt-Ni八面体和研究其合成，合成后的处理，和元素分布，使用先进的电子显微镜。我们评估的电催化ORR的性能和稳定性，并成功地获得一个更深层次的理解增强的稳定性的一类新的相对较大的，活性的，和长寿命的钼掺杂的Pt-Ni八面体催化剂的PEMFC的阴极。
Over the past decade, advances in the colloidal syntheses of octahedral-shaped Pt-Ni alloy nanocatalysts for use in fuel cell cathodes have raised our atomic-scale control of particle morphology and surface composition, which, in turn, helped raise their catalytic activity far above that of benchmark Pt catalysts. Future fuel cell deployment in heavy-duty vehicles caused the scientific priorities to shift from alloy particle activity to stability. Larger particles generally offer enhanced thermodynamic stability, yet synthetic approaches toward larger octahedral Pt-Ni alloy nanoparticles have remained elusive. In this study, we show how a simple manipulation of solvothermal synthesis reaction kinetics involving depressurization of the gas phase at different stages of the reaction allows tuning the size of the resulting octahedral nanocatalysts to previously unachieved scales. We then link the underlying mechanism of our approach to the classical "LaMer" model of nucleation and growth. We focus on large, annealed Mo-doped Pt-Ni octahedra and investigate their synthesis, post-synthesis treatments, and elemental distribution using advanced electron microscopy. We evaluate the electrocatalytic ORR performance and stability and succeed to obtain a deeper understanding of the enhanced stability of a new class of relatively large, active, and long-lived Mo-doped Pt-Ni octahedral catalysts for the cathode of PEMFCs.