Cobalt (Co) mainly exists in two allotropic forms: a low temperature hexagonal close-packed (HCP) structure and a high temperature face-centered cubic (FCC) structure. However, annealing at high temperature only induces the formation of FCC-Co on the surface of a bulk sample and fabrication of bulk FCC-Co is still a great challenge. In this work, nanoporous FCC-Co with a macroscopic dimension is successfully fabricated via a vapor phase alloying (VPA)–vapor phase dealloying (VPD) strategy using zinc (Zn) as the vapor source. Moreover, the thickness of the nanoporous layer could be modulated by adjusting the VPA time. The bulk nanoporous FCC-Co with different shapes and sizes can be fabricated owing to the flexibility and reactivity of the Zn vapor. Both the temperature effect and the size influence contribute to the formation of bulk FCC-Co during the VPD process. In addition, nanoporous FCC-Co shows different magnetic properties as benchmarked with pristine HCP-Co. Our findings provide a new methodology for the preparation of bulk nanoporous FCC-Co which may exhibit unique properties and potential applications.

中文翻译：

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具有面心立方结构的块状纳米多孔钴的气相脱合金驱动合成

钴（Co）主要以两种同素异形体存在：低温六方密堆积（HCP）结构和高温面心立方（FCC）结构。然而，高温退火只会诱导大块样品表面形成 FCC-Co，因此大块 FCC-Co 的制备仍然是一个巨大的挑战。在这项工作中，通过以下方法成功制造了具有宏观尺寸的纳米多孔 FCC-Co使用锌 (Zn) 作为蒸汽源的气相合金化 (VPA)-气相脱合金 (VPD) 策略。此外，纳米多孔层的厚度可以通过调节 VPA 时间来调节。由于锌蒸气的灵活性和反应性，可以制造具有不同形状和尺寸的块状纳米多孔 FCC-Co。在 VPD 过程中，温度效应和尺寸影响都有助于形成块状 FCC-Co。此外，纳米多孔 FCC-Co 显示出与原始 HCP-Co 基准不同的磁性。我们的发现为制备块状纳米多孔 FCC-Co 提供了一种新方法，该方法可能具有独特的性质和潜在的应用。