Nano zero-valent iron (nZVI) and its composite materials have been extensively studied in the field of environmental remediation. However, the oxidation and agglomeration of nZVI limits the large-scale application of nZVI in environmental remediation. This study developed a two-step method to prepare stable carbon-coated nZVI (Fe⁰@C) which combined hydrothermal carbonization and carbothermal reduction methods and used glucose and iron oxide (Fe₃O₄) as precursors. When the carbothermal reduction temperature was 700 °C and the elemental molar ratio of carbon to iron was 22:1, stable Fe⁰@C can be generated. The nZVI particles are encapsulated by mesoporous carbon and embedded in the carbon spheres. The unique structure of carbon coating not only inhibits the agglomeration of nZVI, but also makes nZVI stable in air for more than 120 days. Not only that, the as-synthesized Fe⁰@C exhibited high catalytic activity toward the degradation of 4-chlorophenol (4-CP) by activating persulfate. Different from conventional nZVI catalysts in generation of sulfate radicals, Fe⁰@C selectively induced hydroxyl radicals for 4-CP degradation. Moreover, Fe⁰@C has been shown to efficiently degrade 4-CP by using the dissolved oxygen in water to form hydroxyl radicals. This study not only provides a simple, green method for the preparation of stabilized nZVI, but also provides the possibility of large-scale application of nZVI in the field of environmental remediation.

纳米零价铁（nZVI）及其复合材料在环境修复领域得到了广泛的研究。然而，nZVI的氧化和结块限制了nZVI在环境修复中的大规模应用。这项研究开发了一种两步法来制备稳定的碳包覆nZVI（Fe ⁰ @C），该方法结合了水热碳化和碳热还原方法，并使用葡萄糖和氧化铁（Fe ₃ O ₄）作为前体。碳热还原温度为700°C且碳铁元素摩尔比为22：1时，Fe ⁰稳定可以生成@C。nZVI颗粒被中孔碳包裹并嵌入碳球中。碳涂层的独特结构不仅可以抑制nZVI的团聚，还可以使nZVI在空气中稳定超过120天。不仅如此，合成后的Fe ⁰ @C通过活化过硫酸盐对4-氯苯酚（4-CP）的降解表现出高催化活性。与常规nZVI催化剂的硫酸根自由基生成不同，Fe ⁰ @C选择性诱导羟基自由基降解4-CP。而且，Fe ⁰通过使用水中溶解的氧形成羟基自由基，已证明@C可以有效降解4-CP。这项研究不仅为稳定的nZVI的制备提供了一种简单，绿色的方法，而且还为nZVI在环境修复领域的大规模应用提供了可能性。