Structure and Catalytic Property of Li–Al Metal Oxides from Layered Double Hydroxide Precursors Prepared via a Facile Solution Route
Structure and Catalytic Property of Li–Al Metal Oxides from Layered Double Hydroxide Precursors Prepared via a Facile Solution Route
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DOI：
10.1021/ie2000264
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发表时间：
2011-05
影响因子：
4.2
通讯作者：
Jia Wang;Zhiyi Lei;H. Qin;Lihong Zhang;Feng Li
中科院分区：
文献类型：
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作者：
Jia Wang;Zhiyi Lei;H. Qin;Lihong Zhang;Feng Li
采用分离成核和溶剂热老化的新方法，从锂铝层状双氢氧化物（LiAl-LDHs）中合成了锂铝混合金属氧化物。采用粉末x射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、热重-差热分析（TG-DTA）、扫描电镜（SEM）和低温氮吸附-脱附实验研究了600℃下合成的LiAl-LDHs及其煅烧产物的理化性质。结果表明，与水和水/乙醇混合溶剂相比，以乙醇为溶剂的LiAl-LDH在老化步骤中得到的颗粒更均匀，粒径更小；特别是煅烧后，混合金属氧化物的表面碱度变化很大，这与它们的晶粒尺寸和表面积密切相关。作为固体碱催化剂用于苯甲醛的Knoevenagel缩合反应。
This paper presents the synthesis of Li–Al mixed metal oxides from Li–Al layered double hydroxides (LiAl-LDHs) by using a novel separate nucleation and solvothermal aging steps method. The physicochemical properties of as-synthesized LiAl-LDHs and resulting calcined products at 600 °C were investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), simultaneous thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscope (SEM), and low-temperature nitrogen adsorption–desorption experiments. The results indicated that uniform LiAl-LDH particles with smaller sizes were obtained by using ethanol as solvent in the aging step, in contrast with those by using water and water/ethanol mixture. Especially, after calcination, the resulting mixed metal oxides showed variable surface basicities, which were strongly dependent on their crystallite sizes and surface areas. When used as solid base catalysts for the Knoevenagel condensation of benzaldehyde...