Characterization of ZnAl2O4 Spinel Obtained by Hydrothermal and Microwave Assisted Combustion Method: A Comparative Study

In this work, zinc aluminate spinel was prepared by two methods of directly synthesis (without calcination): microwave assisted combustion and hydrothermal method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2-adsorption/desorption isotherms. The XRD patterns confirmed the formation of cubic ZnAl2O4 spinel structure with no secondary phases for both synthesis routes, whereas the hydrothermal method yielded powders with crystallite size 3 times smaller (6.9 nm), as compared to the powders produced by microwave assisted combustion method (25.6 nm). The micrographs revealed agglomerated powders with plate-like morphologies for both routes. Nitrogen adsorption/desorption isotherms (BET) revealed higher surface area (183 m2.g-1) and greater pore volume (0.173 cm3.g-1) for ZnAl2O4 powders prepared by the hydrothermal method.

本研究采用两种无需煅烧的直接合成方法制备铝酸锌尖晶石：微波辅助燃烧法与水热法。采用X射线衍射（X-ray diffraction, XRD）、扫描电子显微镜（scanning electron microscopy, SEM）以及氮气吸附-脱附等温线对所得材料进行了表征。XRD图谱证实，两种合成路线均成功制备出立方相ZnAl₂O₄尖晶石结构，且无杂相生成；相较于微波辅助燃烧法制备的粉体（晶粒尺寸为25.6 nm），水热法所得粉体的晶粒尺寸仅为其三分之一（6.9 nm）。扫描电镜图像显示，两种方法制备的粉体均呈团聚态，且形貌为片状。氮气吸附-脱附等温线（BET）测试结果表明，水热法制备的ZnAl₂O₄粉体具有更高的比表面积（183 m²·g⁻¹）与更大的孔体积（0.173 cm³·g⁻¹）。