Pd-doped Ni nanoparticle-modified N-doped carbon nanocatalyst with high Pd atom utilization for the transfer hydrogenation of nitroarenes
Pd-doped Ni nanoparticle-modified N-doped carbon nanocatalyst with high Pd atom utilization for the transfer hydrogenation of nitroarenes
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DOI：
10.1039/c7gc03710d
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发表时间：
2018-03-07
期刊：
影响因子：
9.8
通讯作者：
Dong, Zhengping
中科院分区：
文献类型：
--
作者：
Cui, Xueliang;Long, Yu;Dong, Zhengping
钯基催化剂能最大限度地利用钯原子，对氢化反应和节约钯资源具有重要意义。本文通过热解聚丙烯腈、三聚氰胺和Ni(NO3)(2)中心点6H(2)O的混合物，成功制备了高度分散的Ni纳米颗粒（NP）修饰的介孔n掺杂碳（Ni/mCN）。然后，用Pd(AcO)(2)处理得到具有高度分散的金属Ni NPs的Ni/mCN材料，Pd2+被Ni NPs自发还原为金属Pd，提供了PdNi NPs基催化剂（PdNi/mCN）。自发还原过程将大部分Pd原子沉积在Ni NPs表面，从而最大限度地利用贵金属Pd。制备的介孔n掺杂碳载体不仅可以提供更大的表面积来吸附反应底物，还可以提高PdNi NPs活性位点的可及性。与其他Pd基催化剂相比，所制备的PdNi/mCN纳米催化剂在环境条件下以甲酸为还原剂在水溶液中对硝基芳烃的转移加氢具有很高的催化活性，这可能是因为PdNi NPs的高度分散和Pd原子的最大利用率，以及mCN的优越结构。此外，PdNi/mCN纳米催化剂具有良好的可回收性和可重复使用性，经过10个反应循环后，催化活性没有明显下降。因此，我们认为本研究将为制备多孔n掺杂碳负载催化剂开辟一个新的前沿，最大限度地利用贵金属，实现绿色和可持续的催化。
Palladium (Pd)-based catalysts with maximum utilization of the Pd atoms are attractive for hydrogenation reactions and conserving Pd resources. Herein, the highly dispersed Ni nanoparticle (NP)-modified mesoporous N-doped carbon (Ni/mCN) was successfully prepared by pyrolyzing a mixture of polyacrylonitrile, melamine and Ni(NO3)(2)center dot 6H(2)O. Then, the resulting Ni/mCN material with highly dispersed metallic Ni NPs was treated with Pd(AcO)(2), and Pd2+ was spontaneously reduced to metallic Pd by the Ni NPs, affording the PdNi NP-based catalyst (PdNi/mCN). The spontaneous reduction process deposits most of the Pd atoms on the surface of the Ni NPs, thus allowing for the maximum utilization of the noble metal Pd. The prepared mesoporous N-doped carbon support can not only provide more surface area to adsorb reaction substrates, but also enhances the accessibility of the active sites of PdNi NPs. The prepared PdNi/mCN nanocatalyst shows a very high catalytic activity for the transfer hydrogenation of nitroarenes using formic acid as the reductant under ambient conditions in aqueous solution, as compared to other Pd-based catalysts, probably because of the highly dispersed PdNi NPs and the maximum utilization of the Pd atoms, as well as the superior structure of mCN. Moreover, the PdNi/mCN nanocatalyst exhibits excellent recyclability and reusability, and the catalytic activity does not obviously decrease after ten reaction cycles. Therefore, we believe that this study should open a new frontier in the preparation of porous N-doped carbon-supported catalysts with maximum utilization of the noble metals for green and sustainable catalysis.