金属有机骨架材料负载镍纳米颗粒催化硝基苯加氢

摘要

The metal-organic frameworks (MOFs), MIL-53(Al), MIL-96(Al), and MIL-120(Al) (MIL: Material Institute of Lavorisier) were synthesized and used as supports, to incorporate low-cost Ni nanoparticles (NPs) by wet impregnation. The samples were used as catalysts in the hydrogenation of nitrobenzene to aniline. The catalyst prepared with MIL- 53(Al) as a support exhibited excel ent catalytic performance. Ni/MIL- 53(Al) heterogeneous catalysts were prepared using nickel nitrate, nickel acetate, and nickel ethanediamine as precursors. Characterization by powder X-ray diffraction, Fourier-transform infrared spectroscopy, inductively coupled plasma spectroscopy, N2 sorption measurements, H2- temperature programmed reduction, and transmission electron microscopy showed that the Ni precursor affected the metal-support interaction, Ni particle size and particle distribution. The catalyst prepared using nickel ethanediamine possessed moderate metal-support interactions, smaller Ni nanoparticles (4-5 nm), and a high Ni distribution. This resulted in its superior catalytic activity, with 100% conversion of nitrobenzene in the hydrogenation. The Ni/MIL-53(Al) catalyst retained its catalytic activity after five cycles, and exhibited a nitrobenzene conversion of ~92%.%以MIL-53(Al)、MIL-96(Al)和MIL-120(Al)(MIL： Material Institute of Lavorisier)三种金属有机骨架材料为载体，采用浸渍法制备了负载廉价金属镍纳米颗粒的催化剂。将其用于催化硝基苯加氢合成苯胺反应，发现以MIL-53(Al)为载体制得的催化剂表现出优异的催化性能。采用不同的镍前驱体，如硝酸镍、醋酸镍、乙二胺合镍，制备了一系列Ni/MIL-53(Al)催化剂。通过X射线衍射、傅里叶变换红外光谱、电感耦合等离子体、N2物理吸附、H2程序升温还原、透射电镜等技术对其进行了表征，研究了镍前驱体对金属-载体相互作用、镍颗粒尺寸以及分散程度的影响。结果表明：以乙二胺合镍为镍前驱体制得的催化剂具有金属-载体相互作用适中、镍纳米颗粒更小(4-5 nm)和分布更均匀的特点，在硝基苯加氢反应中表现出优异的催化性能，硝基苯转化率达到100%。回收重复使用5次后，此催化剂仍保持催化活性，硝基苯转化率达92%。