Nickel nanoparticles are gaining increasing attention in catalysis due to their versatile catalytic action. A novel, low-cost and facile method was developed in this work to synthesize carbon microsphere-supported metallic nickel nanoparticles (Ni-NP/C) for heterogeneous catalysis. The synthesis was based on carbonizing a polystyrene-based cation exchange resin loaded with nickel ions at temperatures between 500 and 1000 °C. The decomposition of the nickel-organic framework resulted in both Ni-NP and carbon microsphere formation. The phase composition, morphology and surface area of these Ni-NP/C microspheres were characterized by powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy and BET analysis. Elemental nickel was found to be the only metal containing phase; fcc-Ni coexisted with hcp-Ni at carbonization temperatures between 500 and 700 °C, and fcc-Ni was the only metallic phase at 800–1000 °C. Graphitization and carbon nanotube formation were observed at high temperatures. The catalytic activity of Ni-NP/C was tested in the reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride, and Ni-NP/C was proved to be an efficient catalyst in this reaction. The relatively easy and scalable synthetic method, as well as the easy separation and catalytic activity of Ni-NP/C, provide a viable alternative to existing nickel nanocatalysts in future applications.

中文翻译：

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碳微球负载金属镍纳米颗粒作为新型多相催化剂及其在还原硝基苯酚中的应用

镍纳米粒子由于其多功能的催化作用而在催化领域受到越来越多的关注。在这项工作中开发了一种新颖、低成本和简便的方法来合成碳微球负载的金属镍纳米粒子 (Ni-NP/C) 用于多相催化。该合成基于在 500 至 1000 °C 的温度下碳化负载有镍离子的聚苯乙烯基阳离子交换树脂。镍-有机骨架的分解导致 Ni-NP 和碳微球的形成。这些 Ni-NP/C 微球的相组成、形貌和表面积通过粉末 X 射线衍射、拉曼光谱、扫描电子显微镜和 BET 分析进行了表征。发现元素镍是唯一含金属的相；fcc-Ni 与 hcp-Ni 在 500 至 700 °C 的碳化温度下共存，而 fcc-Ni 是 800-1000 °C 的唯一金属相。在高温下观察到石墨化和碳纳米管形成。Ni-NP/C 在硼氢化钠还原 4-硝基苯酚为 4-氨基苯酚的过程中测试了 Ni-NP/C 的催化活性，证明 Ni-NP/C 是该反应的有效催化剂。相对简单和可扩展的合成方法，以及 Ni-NP/C 的容易分离和催化活性，为未来应用中现有镍纳米催化剂提供了可行的替代方案。Ni-NP/C 在硼氢化钠还原 4-硝基苯酚为 4-氨基苯酚的过程中测试了 Ni-NP/C 的催化活性，证明 Ni-NP/C 是该反应的有效催化剂。相对简单和可扩展的合成方法，以及 Ni-NP/C 的容易分离和催化活性，为未来应用中现有镍纳米催化剂提供了可行的替代方案。Ni-NP/C 在硼氢化钠还原 4-硝基苯酚为 4-氨基苯酚的过程中测试了 Ni-NP/C 的催化活性，证明 Ni-NP/C 是该反应的有效催化剂。相对简单和可扩展的合成方法，以及 Ni-NP/C 的容易分离和催化活性，为未来应用中现有镍纳米催化剂提供了可行的替代方案。