Nitrogen-doped graphene aerogel microspheres (rGNAMs) are prepared by electrospraying the graphene oxide dispersion with pyrrole and an oxidation agent and then subjecting it to freeze-drying and thermal annealing. The rGNAMs possess a high surface area, an interconnected pore structure, and uniform N doping. The Pt nanoparticles (Pt NPs) are loaded into rGNAMs through a hydrothermal reduction reaction to obtain the Pt/rGNAM composite catalyst for methanol electrooxidation. The N-doping structure of rGNAMs can improve the loading ratio of Pt on the carrier, decrease the dimension of Pt NPs, homogenize the dispersion of Pt NPs, and increase the content of Pt(111) crystal planes. Consequently, the oxidation activity of Pt/rGNAMs to methanol is improved compared to that without N doping. The optimized Pt/rGNAM composites used as anode electrocatalysts display a remarkable mass activity of 840.11 mA mg^–1 for methanol electrooxidation, which is about 4.9, 2.9, and 2.7 times higher than that of Pt/C, Pt/rGNAB (Pt/N-doped graphene aerogel bulk), and Pt/rGNAS (Pt/N-doped graphene aerogel millimeter spheres), respectively. Moreover, the Pt/rGNAMs also show superior long-term electrocatalytic stability. This work develops a new Pt/rGNAMs composite for potential application in fuel cells.

中文翻译：

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氮掺杂石墨烯气凝胶微球用作甲醇氧化的电催化剂载体

氮掺杂石墨烯气凝胶微球 (rGNAMs) 是通过用吡咯和氧化剂电喷雾氧化石墨烯分散体，然后对其进行冷冻干燥和热退火来制备的。rGNAMs 具有高表面积、相互连接的孔结构和均匀的 N 掺杂。Pt纳米颗粒（Pt NPs）通过水热还原反应负载到rGNAMs中，得到用于甲醇电氧化的Pt/rGNAM复合催化剂。rGNAMs的N掺杂结构可以提高Pt在载体上的负载率，减小Pt NPs的尺寸，使Pt NPs的分散均匀，增加Pt(111)晶面的含量。因此，与没有 N 掺杂的情况相比，Pt/rGNAMs 对甲醇的氧化活性有所提高。^–1用于甲醇电氧化，分别是 Pt/C、Pt/rGNAB（Pt/N 掺杂石墨烯气凝胶体）和 Pt/rGNAS（Pt/N 掺杂石墨烯气凝胶）的 4.9、2.9 和 2.7 倍毫米球），分别。此外，Pt/rGNAMs 还表现出优异的长期电催化稳定性。这项工作开发了一种新的 Pt/rGNAMs 复合材料，可用于燃料电池。