以水滑石及类水滑石为前体制备的Ni、Mg、Al混合氧化物的合成和表征

采用了BET、XRD、TG-DSC、TPR、FTIR、微量量热吸附和异丙醇催化反应等测试方法，对以共沉淀法合成的水滑石(HT)和类水滑石(HTLcs)为前体制备的4Mg/Al、3Ni/Mg/Al、3.5Ni/0.5Mg/Al和4Ni/Al混合氧化物和前体进行了研究。测定表明：制备的混合氧化物的比表面积较大、随着镍含量的增大而降低。由于Ni²⁺离子的氧化还原属性，Ni²⁺离子进入后，削弱了HT层对阴离子的键合能力，从而使得样品的热分解温度及热稳定性降低，导致焙烧后

Synthesis and Characterization of Ni, Mg, Al Mixed Oxides from Hydrotalcite and Hydrotalcite-like Precursors

Various measuring methods, such as BET, XRD, TG-DSC, TPR, FTIR, microcalorimetric adsorption and isopropanol catalytic reaction were used to perform the studies of the samples of 4Mg/Al, 3Ni/Mg/Al, 3.5Ni/0.5Mg/Al and 4Ni/Al mixed oxides, which were obtained from the calcination of the precursors of the hydrotalcite (HT) and the Ni-containing hydrotalcite-like compounds (HTLcs) preparing with the coprecipitation method. The results showed that the specific surface areas of the mixed oxides derived from the HT and HTLcs precursors were larger whereas the specific surface areas for these samples decreased with the addition of Ni²⁺ and the increase of the Ni²⁺ content in the samples. After the nickel cations were introduced into the HT structure, due to the redox properties of the nickel cations, the binding abilities of the HT layers attracting the interlayer anions were weakened, and then enabled the thermal decomposition temperature and the thermostability to descend. And after calcination, the specific surface areas of the Ni-containing mixed oxides were lower than that of the 4Mg/Al sample. In TPR process, the 4Mg/Al sample was not reduced, while the reduction of the Ni-containing mixed oxide was via a path from Ni²⁺ to Ni⁰. The surface of the mixed oxide was showed to contain the acidic sites and the basic sites, and with the change of the Ni²⁺ content in the sample some adjustments were gained with the acidic sites and the basic sites. The FTIR indicated that on most of the surface of the Ni-containing mixed oxide the surface sites were the Lewis acid sites, and the Br?nsted acid sites were almost nil. The acetone selectivity of the isopropanol catalytic reaction was the highest, which indicated that the redox surface sites on these samples were in the dominant position. Due to the addition of Ni and the enhancement of the Ni content in these samples, the conversion of the isopropanol catalytic reaction increased, too.