Xin Song,Fangjun Shao,Zijiang Zhao,Xiaonian Li,Zhongzhe Wei,Jianguo Wang
Precise regulation of reaction selectivity at high conversions is the key to non-terminated alkyne semi-hydrogenation. Herein, a support modification strategy was employed to incorporate trace amounts of Mg elements into alumina support. The modified support loaded Pd catalyst optimized the activity and selectivity of the non-terminated alkyne semi-hydrogenation reaction. The TEM and XRD characterization of the catalysts demonstrated the entry of Mg elements into the Al 2 O 3 lattice to achieve the modification of the support. For the 2-butyne-1-ol semi-hydrogenation reaction, the Pd 0.5 /Mg 1 @Al 2 O 3 catalyst showed 99 % conversion and 97 % selectivity of the cis product at hydrogen pressure of 0.1 MPa and 25 °C. The introduced Mg element changed the electronic structure of Pd nanoparticles in the catalyst. The precise regulation of the 2-butyne-1-ol semi-hydrogenation reaction was achieved by adjusting the ratio of Pd 0 to Pd 2+ using the synergistic effect of Pd 0 and Pd 2+ .
Haiyang Xie,Dan Tang,Yanjuan Zhang,Zuqiang Huang,Huayu Hu,Qian He,Hongbing Ji,Tao Gan
The design of non-noble metal single-atom catalysts (SACs) with superior performance for semi-hydrogenation of alkynol to alkenol is remarkable but challenging. Herein, fluorine-tuned Fe SACs supported on N, F-codoped carbon (Fe 1 -NFC) with a Fe-N 4 F 1 structure is successfully prepared via a complexation method. The axial F-doping can modulate the electronic structure of the metalloporphyrin-like active sites (Fe-N 4 ), promoting the transfer of electrons from Fe atoms to F atoms to form electron-deficient Fe δ+ species. As a result, the Fe 1 -NFC catalyst shows a remarkable activity for the semi-hydrogenation of 2-methyl-3-butyn-2-ol to 2-methyl-3-buten-2-ol under mild conditions, with a TOF of 9163 h −1 and a selectivity of 96 % at 97 % conversion, both much higher than that of the Fe SACs supported on N-doped carbon (Fe 1 -NC). Density functional theory (DFT) calculations reveal that the excellent catalytic activity is attributed to the interfacial electronic effect of Fe species induced by axial F-doping, thereby enhancing the exothermic adsorption of alkynol on the Fe-N 4 F 1 structures and accelerating the desorption of alkenol to against the overhydrogenation.
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