Cu-Zr复合氧化物催化耦合甘油和CO_(2)合成碳酸甘油酯

Synthesis of glycerol carbonate from glycerol and CO_(2) over Cu-Zr complex oxide

采用水热法合成了一系列不同Cu-Zr物质的量比的Cu1-xZrxO_(2)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CO_(2)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,Cu0.99Zr0.01O_(2)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ZrO_(2)相比,Cu1-xZrxO_(2)复合氧化物在甘油与CO_(2)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Cu0.99Zr0.01O_(2)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。

A series of Cu1−xZrxO_(2) bimetallic oxides with different Cu-Zr molar ratios for glycerol carbonate synthesis from glycerol and CO_(2) 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 Cu0.99Zr0.01O_(2) catalyst had the best catalytic performance.The conversion of glycerol and the selectivity of glycerol carbonate reached 64.1%and 85.9%,respectively.Cu1−xZrxO_(2) complex oxide exhibited better activity than pure CuO and pure ZrO_(2).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.