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Liquid-phase hydrogenation of cinnamaldehyde over Cu-Au/SiO2 catalysts

Authors

  • Xiang Yuan,

    1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
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  • Jianwei Zheng,

    1. School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
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  • Qian Zhang,

    1. School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
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  • Shuirong Li,

    1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
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  • Yanhui Yang,

    Corresponding author
    1. School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
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  • Jinlong Gong

    Corresponding author
    1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
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Abstract

The synthesis, characterization, and application of silica-supported Cu-Au bimetallic catalysts in selective hydrogenation of cinnamaldehyde are described. The results showed that Cu-Au/SiO2 bimetallic catalysts were superior to monometallic Cu/SiO2 and Au/SiO2 catalysts under identical conditions. Adding a small amount of gold (6Cu-1.4Au/SiO2 catalyst) afforded eightfold higher catalytic reaction rate compared to Cu/SiO2 along with the high selectivity (53%, at 55% of conversion) toward cinnamyl alcohol. Characterization techniques such as x-ray diffraction, H2 temperature-programmed reduction, ultraviolet-visible spectroscopy, transmission electron microscopy, Fourier-transform infrared spectra of chemisorbed CO, and x-ray photoelectron spectroscopy were employed to understand the origin of the catalytic activity. A key genesis of the high activity of the Cu-Au/SiO2 catalyst was ascribed to the synergistic effect of Cu and Au species: the Au sites were responsible for the dissociative activation of H2 molecules, and Cu0 and Cu+ sites contributed to the adsorption-activation of C[DOUBLE BOND]C and C[DOUBLE BOND]O bond, respectively. A combined tuning of particle dispersion and its surface electronic structure was shown as a consequence of the formation of Au-Cu alloy nanoparticles, which led to the significantly enhanced synergy. A plausible reaction pathway was proposed based on our results and the literature. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3300–3311, 2014

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