MOF衍生的高选择性加氢芳香硝基化合物的石墨碳包覆镍催化剂

针对芳香硝基化合物的催化选择性加氢反应，开发可替代贵金属催化剂的低成本、高效非贵金属催化剂，对于芳香胺类化合物的绿色生产具有重要意义。利用简易、可规模化的制备方法，以镍—2,5-吡啶二羧酸金属有机框架为前驱体，热解制备了氮掺杂石墨碳包覆镍纳米催化材料（Ni@CN）。采用X射线衍射、扫描电镜、透射电镜、元素分析、N2吸脱附等检测手段对Ni@CN的物化性质进行了表征，并对其催化性能进行了评价。结果表明，Ni@CN可在温和条件下（85℃，1.0 MPa H2)高效加氢含取代官能团的芳香硝基化合物生成对应的芳香胺类化合物。对比试验表明，镍纳米颗粒是Ni@CN的加氢活性中心，而石墨碳壳的存在有利于优先吸附硝基官能团。此外，进一步考察了Ni@CN的循环使用性能以及抗硫化物中毒的特性。

Chemoselective catalytic hydrogenation of nitroarenes using MOF-derived graphitic carbon layers encapsulated Ni catalysts

Replacement of precious noble metal catalysts with cost-effective, non-noble heterogeneous catalysts for chemoselective hydrogenation of nitroarenes holds tremendous promise for the clean synthesis of nitrogen-containing chemicals. Graphitic carbon layers encapsulated Ni catalysts (Ni@CN) are generated by a facile, scalable and straightforward strategy via the pyrolysis of 2,5-pyridinedicarboxylic acid coordinated Ni-MOF acting as the precursor. Physicochemical properties of the Ni@CN catalysts have been investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, elemental analysis and N2 adsorption-desorption analysis. The Ni@CN catalysts were found to be highly efficient in the chemoselective hydrogenation of various nitroarenes with other functional groups towards corresponding anilines under mild reaction conditions (85 °C, 1.0 MPa of H2 pressure). Based on the results of controlled tests, the catalytic activity can be attributed to the Ni NPs, while the presence of graphitic carbon layers favors the preferential adsorption of the nitro groups. The recyclability and anti-sulfur poisoning capability of Ni@CN were also investigated.