Fan Xiuling, Zhao Ming, Li Tianhao, Zhang Lian Ying, Jing Maoxiang, Yuan Weiyong, Li Chang Ming
Ningbo Research Institute, Zhejiang University, Ningbo 315100, China.
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Nanoscale. 2021 Nov 11;13(43):18332-18339. doi: 10.1039/d1nr05988b.
Highly conductive cocatalysts with great promotion effects are critical for the development of pristine graphene supported Pt-based catalysts for the methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs). However, identification of these cocatalysts and controlled fabrication of Pt/cocatalyst/graphene hybrids with superior catalytic performance present great challenges. For the first time, pristine graphene supported N-rich carbon (NC) has been controllably fabricated ionic-liquid-based self-assembly for growth of small and uniformly dispersed Pt NP chains to improve the MOR catalytic activity. It is discovered that the NC serves simultaneously as a linker to facilitate nucleation of Pt, a stabilizer to restrict its growth and aggregation, and a structure-directing agent to induce the formation of Pt NP chains. The obtained nanohybrid shows a much higher forward peak current density than commercial Pt/C and most reported noncovalently functionalized carbon (NFC) supported Pt catalysts, a lower onset potential than almost all commercial Pt/C and NFC supported Pt, and greatly enhanced durability compared to graphene supported Pt NPs and commercial Pt/C. The superior catalytic performance is ascribed to the uniformly dispersed, small-diameter, and short Pt NP chains supported on highly conductive G@NC providing high ECSA and improved CO tolerance and the NC with high content of graphitic N greatly enhancing the intrinsic activity and CO tolerance of Pt and offering numerous binding sites for robustly attaching Pt. This work not only identifies and controllably fabricates a novel cocatalyst to significantly promote the catalytic activity of pristine graphene supported Pt but provides a facile and economical strategy for the controlled synthesis of high-performance integrated catalysts for the MOR in DMFCs.
具有显著促进作用的高导电性助催化剂对于开发用于直接甲醇燃料电池（DMFC）中甲醇氧化反应（MOR）的原始石墨烯负载铂基催化剂至关重要。然而，识别这些助催化剂以及可控地制备具有优异催化性能的Pt/助催化剂/石墨烯杂化物面临巨大挑战。首次通过基于离子液体的自组装可控地制备了原始石墨烯负载的富氮碳（NC），用于生长小且均匀分散的Pt NP链，以提高MOR催化活性。发现NC同时充当促进Pt成核的连接体、限制其生长和聚集的稳定剂以及诱导Pt NP链形成的结构导向剂。所获得的纳米杂化物显示出比商业Pt/C和大多数报道的非共价功能化碳（NFC）负载的Pt催化剂高得多的正向峰值电流密度，比几乎所有商业Pt/C和NFC负载的Pt更低的起始电位，并且与石墨烯负载的Pt NPs和商业Pt/C相比，耐久性大大提高。优异的催化性能归因于负载在高导电性G@NC上的均匀分散、小直径和短的Pt NP链提供了高的电化学活性表面积（ECSA）并改善了CO耐受性，以及具有高石墨氮含量的NC大大提高了Pt的本征活性和CO耐受性并提供了大量用于牢固附着Pt的结合位点。这项工作不仅识别并可控地制备了一种新型助催化剂以显著促进原始石墨烯负载Pt的催化活性，而且为DMFC中MOR的高性能集成催化剂的可控合成提供了一种简便且经济的策略。
