Angel Gyen Ming A, Mansor Noramalina, Jervis Rhodri, Rana Zahra, Gibbs Chris, Seel Andrew, Kilpatrick Alexander F R, Shearing Paul R, Howard Christopher A, Brett Dan J L, Cullen Patrick L
Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
Nanoscale. 2020 Aug 14;12(30):16113-16122. doi: 10.1039/d0nr03326j. Epub 2020 Jul 23.
Creating effective and stable catalyst nanoparticle-coated electrodes that can withstand extensive cycling is a current roadblock in realising the potential of polymer electrolyte membrane fuel cells. Graphene has been proposed as an ideal electrode support material due to its corrosion resistance, high surface area and high conductivity. However, to date, graphene-based electrodes suffer from high defect concentrations and non-uniform nanoparticle coverage that negatively affects performance; moreover, production methods are difficult to scale. Herein we describe a scalable synthesis for Pt nanoparticle-coated graphene whereby PtCl is reduced directly by negatively charged single layer graphene sheets in solution. The resultant nanoparticles are of optimal dimensions and can be uniformly dispersed, yielding high catalytic activity, remarkable stability, and showing a much smaller decrease in electrochemical surface area compared with an optimised commercial catalyst over 30 000 cycles. The stability is rationalised by identical location TEM which shows minimal nanoparticle agglomeration and no nanoparticle detachment.
制造出能经受大量循环的有效且稳定的催化剂纳米颗粒包覆电极，是实现聚合物电解质膜燃料电池潜力的当前障碍。石墨烯因其耐腐蚀性、高表面积和高导电性，已被提议作为理想的电极支撑材料。然而，迄今为止，基于石墨烯的电极存在高缺陷浓度和纳米颗粒覆盖不均匀的问题，这对性能产生负面影响；此外，生产方法难以规模化。在此，我们描述了一种用于铂纳米颗粒包覆石墨烯的可扩展合成方法，即通过溶液中带负电荷的单层石墨烯片直接还原PtCl。所得纳米颗粒尺寸最优且能均匀分散，具有高催化活性、显著的稳定性，并且在30000次循环中，与优化的商业催化剂相比，电化学表面积的减小要小得多。通过相同位置透射电子显微镜观察发现纳米颗粒团聚极少且无纳米颗粒脱离，从而解释了这种稳定性。
