Kandare Everson, Hossenlopp Jeanne M
Department of Chemistry, Marquette University, P. O. Box 1881, Milwaukee, Wisconsin 53201-1881, USA.
Inorg Chem. 2006 May 1;45(9):3766-73. doi: 10.1021/ic060071k.
Two hydroxy double salts (HDSs), zinc copper hydroxy acetate (ZCA) and zinc nickel hydroxy acetate (ZNA), and an analogous layered compound, zinc hydroxy acetate (ZHA), have been prepared by a coprecipitation method. The thermal degradation of these materials was characterized via thermogravimetric analysis (TGA), differential thermal analysis (DTA), and TGA coupled with Fourier transform infrared spectroscopy of gas-phase products, TGA-FTIR. Loss of physisorbed and interlayer H2O was observed between 50 and 150 degrees C for all compounds. Acetic acid, acetone, water, and CO2 were released at high temperatures with relative acetone yields found to be dependent on precursor identity, with very little formed from ZCA compared with ZHA and ZNA. Combined FTIR and XRD analysis of solid residues extracted at different points in the heating profile suggests that ketonization occurs via dissociative adsorption of acetic acid on ZnO surfaces. Nanometer-sized ZnO particles were formed from ZHA, showing slight preferential growth in the ZnO (002) lattice direction, while the presence of a second metal, Ni or Cu, served to retard ZnO crystallite growth at temperatures below 600 degrees C and eliminate preferential growth. ZCA leads to the formation of reduced copper species (metallic copper and Cu2O) when heated to 250 degrees C.
通过共沉淀法制备了两种羟基复盐（HDSs），即羟基乙酸锌铜（ZCA）和羟基乙酸锌镍（ZNA），以及一种类似的层状化合物羟基乙酸锌（ZHA）。通过热重分析（TGA）、差示热分析（DTA）以及热重分析与气相产物的傅里叶变换红外光谱联用（TGA-FTIR）对这些材料的热降解进行了表征。所有化合物在50至150摄氏度之间均观察到物理吸附的和层间的H2O损失。高温下释放出乙酸、丙酮、水和CO2，发现相对丙酮产率取决于前驱体的性质，与ZHA和ZNA相比，ZCA形成的丙酮很少。对在加热曲线不同点提取的固体残渣进行傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）联合分析表明，酮化反应是通过乙酸在ZnO表面的解离吸附发生的。由ZHA形成了纳米尺寸的ZnO颗粒，在ZnO（002）晶格方向上显示出轻微的择优生长，而第二种金属Ni或Cu的存在有助于在600摄氏度以下的温度下抑制ZnO微晶生长并消除择优生长。当加热到250摄氏度时，ZCA会导致形成还原态的铜物种（金属铜和Cu2O）。
