Converting Fluorinated Graphite to Nitridated Graphene for Room-Temperature Magnetic Applications
摘要
Nitrogen doping has emerged as a promising strategy for achieving intrinsic magnetism in graphene, yet experimental demonstrations at room temperature remain limited. This work reports on the achievement of magnetic, metal-free nitrogen-doped graphene derived from fluorinated graphite. The material was obtained by reducing the fluorine content to 0.25 at.% from commercial fluorinated graphite and incorporating 5.5 at.% nitrogen via a two-stage annealing process, as verified by x-ray photoelectron spectroscopy. Fourier transform infrared analysis confirmed the successful incorporation of functional groups, while the presence of a broad, prominent peak at 26.17° in the x-ray diffraction pattern indicated a graphene structure. Atomic force microscopy confirmed the graphene layer thickness as approximately 2 nm. Magnetic characterization using vibrating-sample magnetometry in the temperature range of 2–300 K showed a significant magnetic response, with magnetization of 0.13 emu g−1 at 300 K, providing direct experimental evidence that nitrogen doping can effectively induce room-temperature magnetism in graphene. Inductively coupled plasma optical emission spectroscopy confirmed that intrinsic magnetic impurities were present at levels contributing only ~10−6 emu, which is five orders of magnitude lower than the observed magnetic saturation. This result confirms that the observed magnetic response is primarily due to extrinsic nitrogen doping.