Abstract:

[Cu(EDTA)]^2- intercalated ZnAl hydrotalcite-like precursors with different Cu proportions were successfully prepared by the co-precipitation method, and then calcined to form mixed metal oxide catalysts. The catalysts were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), N₂ physical adsorption and desorption, transmission electron microscopy (TEM), N₂O titration test, inductively coupled plasma-emission spectroscopy (ICP-OES), H₂ programmed temperature-raising reduction (H₂-TPR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the catalytic performance of these CuZnAl catalysts in CO hydrogenation reaction was evaluated. The results indicated that smaller CuO particles were beneficial to increasing the oxygen vacancies, Cu dispersion and Cu specific surface area, enhancing the activation of reactants, and improving catalytic activity. Notably, compared with other catalysts, the HT-Cu_0.5(EDTA) catalyst exhibited stronger domain-limiting effect of the hydrotalcite-like laminates, leading to the smaller CuO particle size, higher Cu dispersion, larger exposed Cu specific surface area, easier reduction to Cu⁰, stronger interaction between Cu species and ZnO on the laminates, and more oxygen vacancies. These features facilitated the adsorption and activation of the reactants, resulting in a remarkable space-time total alcohol yield of 1448.9mg ROH/(g Cu·h), demonstrating superior catalytic performance.

Key words: hydrotalcite-like, intercalation ion, catalyst, syngas, low-carbon alcohols

摘要：

采用共沉淀法成功制备了不同比例[Cu(EDTA)]^2-插层ZnAl类水滑石前体，经焙烧后形成混合金属氧化物催化剂。通过X射线粉末衍射（XRD）、傅里叶红外变换（FTIR）、N₂物理吸脱附、透射电子显微镜（TEM）、N₂O滴定测试、电感耦合等离子体发射光谱（ICP-OES）、H₂程序升温还原（H₂-TPR）和X射线光电子能谱（XPS）等方法对催化剂结构进行表征分析，并考察了其催化CO加氢制取低碳醇的性能。结果表明，较小的CuO颗粒可以增加氧空位数量，提高Cu分散度和Cu比表面积，增强对反应物的活化，进而提高催化活性。相较于其他比例的催化剂，HT-Cu_0.5（EDTA）催化剂中类水滑石层板的限域作用最强，导致CuO颗粒尺寸最小，Cu分散度最高，暴露的Cu比表面积最大且更易还原为Cu⁰，Cu物种与层板上的ZnO相互作用较强，氧空位相对含量最多，有利于促进反应物的吸附和活化，其总醇的时空收率高达1448.9mg ROH/(g Cu·h)，表现出最优的催化性能。

关键词: 类水滑石, 插层离子, 催化剂, 合成气, 低碳醇