Cu-Zr复合氧化物催化耦合甘油和CO2合成碳酸甘油酯

Synthesis of glycerol carbonate from glycerol and CO2 over Cu-Zr complex oxide

  • 摘要: 采用水热法合成了一系列不同Cu-Zr物质的量比的Cu1−xZrxO2双金属氧化物,以此为催化剂,将生物柴油生产过程副产物甘油与温室气体CO2耦合反应制备精细化工产品碳酸甘油酯。结果表明,Zr掺杂量不同,催化剂对甘油羰基化反应效果呈现明显差距,最佳反应条件下,Cu0.99Zr0.01O2催化剂具有最佳催化性能,甘油转化率和碳酸甘油酯选择性分别达到64.1%和85.9%。并且发现与纯CuO和纯ZrO2相比,Cu1−xZrxO2复合氧化物在甘油与CO2耦合反应体系中表现出更强的催化活性,结合X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、N2吸附-脱附、程序升温还原(H2-TPR)、程序升温脱附(TPD)、傅里叶变换红外光谱(FT-IR)等表征手段,推测高活性与Zr在CuO表面的分散程度、催化剂表面氧物种含量及酸碱性位点数量有关。此外,为了研究催化剂的稳定性,以Cu0.99Zr0.01O2催化剂作为基准进行了循环性能测试,结果表明,经过六次循环后,甘油的转化率和碳酸甘油酯的选择性未发生明显变化,说明该催化剂稳定性良好。

     

    Abstract: A series of Cu1−xZrxO2 bimetallic oxides with different Cu-Zr molar ratios for glycerol carbonate synthesis from glycerol and CO2 were prepared by hydrothermal method. The results found that the performance was significantly affected by the Zr doping amounts. Under the optimal reaction conditions, the Cu0.99Zr0.01O2 catalyst had the best catalytic performance. The conversion of glycerol and the selectivity of glycerol carbonate reached 64.1% and 85.9%, respectively. Cu1−xZrxO2 complex oxide exhibited better activity than pure CuO and pure ZrO2. The structures, morphologies and surface properties of the catalysts were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption and desorption, Temperature programmed reduction (H2-TPR), Temperature programmed desorption (TPD) and Fourier Transform Infrared Spectroscopy (FT-IR). It is speculated that the high activity is related to the degree of dispersion of Zr on the surface of CuO, the surface content of oxygen species and the number of acidic-basic sites. In addition, catalytic activity did not change significantly after six cycles, indicating the excellent stability of the catalyst.

     

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