Chen Manyu, Cui Yan, Qian Wei, Peng Qingpo, Wang Jiajia, Gong Honghui, Fang Jian, Dai Sheng, Hou Zhenshan
Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.
Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
Langmuir. 2020 Oct 6;36(39):11589-11599. doi: 10.1021/acs.langmuir.0c02153. Epub 2020 Sep 23.
Catalytic hydrogenations represent fundamental processes and allow for atom-efficient and clean functional group transformations for the production of chemical intermediates and fine chemicals in chemical industry. Herein, the Ru/CoO nanocomposites have been constructed and applied as nanocatalysts for the hydrogenation of phenols and furfurals into the corresponding cyclohexanols and tetrahydrofurfuryl alcohols, respectively. The functionalized ionic liquid acted not only as a ligand for stabilizing the Ru/CoO nanocatalyst but also as a thermoregulated agent. The as-obtained nanocatalyst showed superior activity, and it could be conveniently recovered the thermoregulating phase separation. In six recycle experiments, the catalysts maintained excellent performance. It was observed that the catalytic performance highly hinged on the molar ratio of Ru to Co in the nanocatalyst. The catalyst characterization was carried out by high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution mass spectrometry, Fourier transform infrared, nuclear magnetic resonance, and UV-vis. Especially, the characterization by HRTEM and HAADF-STEM images of the nanocatalyst demonstrated that Ru(0) and Co(II) species were distributed uniformly and the Ru and Co(II) species were close to each other. However, Co(0) was generated and an electronic transfer from Co to Ru species could occur under the hydrogenation conditions. The C NMR characterization indicated further that Co(II) sites were mainly responsible for phenol adsorption. Meanwhile, the adjacent electron-rich Ru(0) sites can promote H dissociation and favor for the sequential hydrogenation.
催化氢化是基础过程，能实现原子经济且清洁的官能团转化，用于化工行业生产化学中间体和精细化学品。在此，构建了Ru/CoO纳米复合材料，并将其用作纳米催化剂，分别将苯酚和糠醛氢化为相应的环己醇和四氢糠醇。功能化离子液体不仅作为配体用于稳定Ru/CoO纳米催化剂，还作为热调节试剂。所制备的纳米催化剂表现出优异的活性，并且通过热调节相分离可方便地回收。在六次循环实验中，催化剂保持了优异的性能。观察到催化性能高度取决于纳米催化剂中Ru与Co的摩尔比。通过高分辨率透射电子显微镜（HRTEM）、高角度环形暗场扫描透射电子显微镜（HAADF-STEM）、X射线光电子能谱、X射线衍射、高分辨率质谱、傅里叶变换红外光谱、核磁共振和紫外可见光谱对催化剂进行了表征。特别是，通过纳米催化剂的HRTEM和HAADF-STEM图像表征表明，Ru(0)和Co(II)物种均匀分布，且Ru和Co(II)物种彼此靠近。然而，在氢化条件下会生成Co(0)，并且可能发生从Co到Ru物种的电子转移。13C NMR表征进一步表明，Co(II)位点主要负责苯酚吸附。同时，相邻的富电子Ru(0)位点可促进H解离并有利于后续氢化。
