Abstract A novel facile and cost-effective approach was developed to fabricate Fe3O4/Pd nanoparticles encapsulated in a nitrogen-doped carbon (NC) shell (Fe3O4/Pd@N–C) through a layer-by-layer assembly method coupled with high-temperature annealing. The Fe3O4/Pd@N–C nanocomposites acted as a high-performance catalyst for the catalytic reduction of Cr (VI) to Cr (III) using formic acid (HCOOH) as the reducing agent. Due to conductive and protective functions of the NC shell, the catalyst had a high stability and catalytic activity, and only needed 3 min were required to convert Cr(VI) to Cr(III). Furthermore, catalytic conditions such as annealing temperature, reaction temperature and Pd loading were optimized. The excellent catalytic performance of Fe3O4/Pd@N–C can be attributed to the following reasons: the thin NC shell, the high disperse of Pd NPs loaded on the Fe3O4, the high content of pyridinic nitrogen and graphitic nitrogen, as well as high surface area up to 110.77 m2 g−1.

中文翻译：

---

轻松合成氮掺杂碳包覆的 Fe3O4/Pd 纳米粒子作为 Cr (VI) 还原的高性能催化剂

摘要 开发了一种新的简便且具有成本效益的方法，通过逐层组装方法与高密度相结合来制造封装在氮掺杂碳（NC）壳（Fe3O4/Pd@N-C）中的 Fe3O4/Pd 纳米粒子。温度退火。Fe3O4/Pd@N-C 纳米复合材料作为一种高性能催化剂，使用甲酸 (HCOOH) 作为还原剂将 Cr (VI) 催化还原为 Cr (III)。由于NC壳的导电和保护功能，催化剂具有较高的稳定性和催化活性，仅需要3分钟即可将Cr(VI)转化为Cr(III)。此外，优化了退火温度、反应温度和钯负载等催化条件。Fe3O4/Pd@N-C 优异的催化性能可归因于以下原因：薄的 NC 壳，