Recently, great efforts have been devoted to improving the catalytic activity and durability of Pt based catalysts for proton exchange membrane fuel cells. Here, surfactant-free PtAg fractal dendritic nanocrystals (NCs) with high surface area were prepared via a facile one-pot reaction. The control synthetic experiments proved that the formation of PtAg fractal dendritic NCs resulted from a kinetics-controlled growth, i.e. the “diffusion limited aggregation” mechanism. Due to their unique structural advantage and clean surface, the as-prepared PtAg fractal dendritic NCs exhibited superior electrochemical catalytic activities and structural stabilities compared with commercial Pt black and Pt/C towards methanol electro-oxidation and oxygen reduction reaction in acidic media. The design strategy presented here may be useful in fabricating other highly active and stable Pt–M catalysts for fuel cells.

中文翻译：

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简便合成具有增强电化学性能的清洁PtAg树突状纳米结构

近来，已经致力于改善用于质子交换膜燃料电池的基于Pt的催化剂的催化活性和耐久性。在这里，通过简单的一锅反应制备了具有高表面积的无表面活性剂的PtAg分形树枝状纳米晶体（NCs）。对照合成实验证明，PtAg分形树突状NC的形成是由动力学控制的生长引起的，即“扩散有限聚集”机制。由于其独特的结构优势和清洁的表面，与市售的Pt黑和Pt / C在酸性介质中进行甲醇电氧化和氧还原反应相比，所制备的PtAg分形树突状NC具有优异的电化学催化活性和结构稳定性。本文提出的设计策略可能对制造其他高活性和稳定的燃料电池Pt-M催化剂有用。