Muravev Aleksandr D, Ivanov Andrei V, Mukhanov Vladimir A, Kulnitskiy Boris A, Maksimova Natalia V, Avdeev Victor V
Chemistry Department, Lomonosov Moscow State University, Leninskie Gory 1-3, Moscow 119991, Russia.
Federal State Budgetary Institution "Technological Institute for Superhard and Novel Carbon Materials of National Research Centre «Kurchatov Institute»", Centralnaya Str. 7a, Troitsk 108840, Russia.
Nanomaterials (Basel). 2025 Sep 4;15(17):1363. doi: 10.3390/nano15171363.
This study demonstrates a novel route to synthesize gold-decorated exfoliated graphite (EG) through graphite intercalation compounds (GICs) with tetrachloroauric acid (HAuCl). We aimed to develop a scalable method for producing EG/Au composites with controlled nanoparticle morphology by investigating the effects of precursor chemistry and thermal expansion conditions. II-stage GIC-HAuCl (average gross-composition: CHAuCl; intercalate layer thickness d = 6.85 Å) was prepared via an exchange reaction of HAuCl with graphite nitrate. Interaction of this GIC with liquid methylamine yielded an occlusive complex, where methylamine-bound HAuCl occupies both interlayer and intercrystalline spaces in the graphite matrix. Methylamine treatment of GIC reduces the onset temperature of exfoliation by ≈100 °C and enhances the expansion efficiency, yielding EG with a low bulk density range of 4-6 g/L when processed at 900 °C in air or nitrogen. Thermal exfoliation of these GICs yielded EG decorated with gold nanoparticles, exhibiting a broad size distribution from a few nanometers to several hundred nanometers, as confirmed by electron microscopy. An X-ray diffraction analysis identified the coexistence of crystalline gold and hexagonal graphite phases, with no detectable impurity phases.
本研究展示了一种通过石墨插层化合物（GICs）与四氯金酸（HAuCl）合成金修饰的膨胀石墨（EG）的新途径。我们旨在通过研究前驱体化学和热膨胀条件的影响，开发一种可扩展的方法来制备具有可控纳米颗粒形态的EG/Au复合材料。通过HAuCl与硝酸石墨的交换反应制备了II阶段GIC-HAuCl（平均总组成：CHAuCl；插层层厚度d = 6.85 Å）。这种GIC与液态甲胺的相互作用产生了一种封闭络合物，其中甲胺结合的HAuCl占据了石墨基质中的层间和晶间空间。用甲胺处理GIC可使剥离起始温度降低约100°C，并提高膨胀效率，在空气或氮气中于900°C处理时，可得到堆积密度低至4-6 g/L的EG。这些GIC的热剥离产生了装饰有金纳米颗粒的EG，电子显微镜证实其尺寸分布范围从几纳米到几百纳米。X射线衍射分析确定了结晶金和六方石墨相共存，未检测到杂质相。
