Transmission electron microscopy (TEM) is a critical tool evaluating nanoscale phenomena that occur in nanomaterials. Although TEM is a high-vacuum instrument, due to the presence of molecules remaining under the equilibrium gas partial pressure, unintended reactions can be thermodynamically driven by various factors during TEM observation. In particular, highly reactive gas molecules, such as oxygen, can react with the specimen and reduce the reliability of the analysis result. In this work, an oxidation reaction caused by the electron beam irradiation and heating in a microscope was studied using pristine copper nanowires (Cu NWs), with a high oxygen affinity. Real-time imaging revealed that the beam irradiation and heat led to a transition of Cu to Cu oxides due to residual oxygen in the microscope. This study also presents a method (i.e., graphene encapsulation) for preventing the unintended oxidation reaction of a TEM specimen. The proposed method is not only effective in inhibiting oxidation of Cu NWs induced by electron beam irradiation and heating, but also effective in preserving specimens for prolonged periods.

透射电子显微镜（TEM）是评估纳米材料中发生的纳米级现象的重要工具。尽管TEM是一种高真空仪器，但由于在平衡气体分压下仍残留有分子，因此在TEM观察期间，各种因素可能会热力学地驱动意外反应。尤其是高反应性的气体分子，例如氧气，可能会与样品发生反应并降低分析结果的可靠性。在这项工作中，使用具有高氧亲和力的原始铜纳米线（Cu NWs）研究了在显微镜下由电子束辐射和加热引起的氧化反应。实时成像显示，由于显微镜中的残留氧气，光束照射和热量导致Cu转变为Cu氧化物。这项研究还提出了一种方法（即 石墨烯封装）以防止TEM样品意外的氧化反应。所提出的方法不仅能有效抑制电子束辐照和加热引起的铜纳米线的氧化，而且能长时间保存标本。