Fe2O3含量对Cu-Fe/铝土矿水煤气变换催化剂结构和性能的影响

利用具有高比表面积和介孔结构的改性铝土矿为载体,采用并流共沉淀法制备不同Fe2O3含量的Cu-Fe/铝土矿催化剂。以水煤气变换反应为探针反应,考察了催化剂性能。利用X射线荧光元素分析(XRF)、X射线粉末衍射(XRD)、H2程序升温还原(H2-TPR)、CO程序升温脱附(CO-TPD)和X射线光电子能谱(XPS)等对催化剂进行了表征。结果表明:负载的Fe2O3能显著提高CuO/改性铝土矿催化剂的水煤气变换活性特别是热稳定性能,且随负载的Fe2O3含量增加而提高,当负载量为20%时达到最佳。其原因是负载的Fe2O3和CuO之间发生了相互作用,形成了类似于CuFe2O4复合氧化物,且随负载的Fe2O3含量的增加而增强,这种相互作用同时促进了CuO和Fe2O3的还原,抑制了CuO的烧结,进而提高了催化剂的性能。

Effect of Fe2O3 Content on Structure and Catalytic Performance of Cu-Fe/Bauxite for Water Gas Shift Reaction

Using modified bauxite with large surface area and mesoporous structure as the support, a series of Cu-Fe/Bauxite catalysts were synthesized with co-precipitation method. The catalysts were characterized by means of X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), S_BET, H₂-temperature-programmed reduction (H₂-TPR) and CO temperature-programmed desorption (CO-TPD) and X-ray photoelectron spectroscopy (XPS). Their catalytic activity in water gas shift (WGS) reaction has also been studied. The results indicate that the WGS reaction activity increases markedly with increasing the content of supported Fe₂O₃ and when the content of Fe₂O₃ is to 20%, the catalyst exhibits the highest activity. Because there exists obvious interaction between supported Fe₂O₃ and CuO to form composite oxide like CuFe₂O₄ and it enhances with increase in Fe₂O₃ content. The interaction promotes the reduction of Fe₂O₃ and CuO and restrains the clotting of CuO, and then the catalytic activity increases.