This work investigates the role of hydroxyl and epoxy bridges in room-temperature ferromagnetism (FM) of pyrolytic graphene oxide nanoplatelets (GOs). Graphene oxide nanoplatelets were synthesized from bamboo pyroligneous acid (BPA), varying oxide coverage (OC) from 5.3% to 13.0%. The amount of hydroxyl and epoxy functional groups in all the GO samples were estimated from results analysis of X-ray photoelectron spectroscopy (XPS). An FM signal was identified, measured at room temperature, which scaled with oxide coverage. Decreased oxide coverage results in enhanced FM. A combination of results from high-resolution transmission electron microscopy (HR-TEM), XPS, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Fourier transform infrared (FTIR), Raman, and electrical characterization allowed constructing an atomic model for each graphene oxide (GO) structure. First-principles calculations of the atomic model suggest that FM is induced by the adsorption of –OH and –O– atoms on graphene nanoplatelets; therefore, their magnetism is a response to the number of uncompensated spins due to topographic defects. These results suggest future possibilities of the magnetism approach of pyrolytic GO in spintronics of advanced sensors and devices.

这项工作研究了羟基和环氧桥在热解氧化石墨烯纳米片 (GO) 的室温铁磁性 (FM) 中的作用。氧化石墨烯纳米片由竹木焦木酸 (BPA) 合成，氧化物覆盖率 (OC) 从 5.3% 到 13.0%。根据 X 射线光电子能谱 (XPS) 的结果分析估计所有 GO 样品中羟基和环氧官能团的数量。确定了在室温下测量的 FM 信号，该信号与氧化物覆盖率成比例。减少的氧化物覆盖导致增强的 FM。高分辨率透射电子显微镜 (HR-TEM)、XPS、能量色散 X 射线光谱 (EDX)、X 射线衍射 (XRD)、电子能量损失光谱 (EELS)、傅里叶变换红外光谱 ( FTIR), 拉曼, 和电气特性允许为每个氧化石墨烯 (GO) 结构构建原子模型。原子模型的第一性原理计算表明，FM 是由 -OH 和 -O- 原子在石墨烯纳米片上的吸附引起的；因此，它们的磁性是对由于地形缺陷导致的未补偿自旋数量的响应。这些结果表明热解 GO 的磁性方法在高级传感器和设备的自旋电子学中的未来可能性。