非晶氧化锆水合物红外研究

摘要

用红外吸收光谱（IR）结合X射线衍射（XRD）、差热（DTA）和热失重分析（TG）详细研究了氧化锆前驱物（溶胶凝胶法制得的非晶态氧化锆水合物）的结构。实验结果表明在非晶态氧化锆水合物中有三种不同的近程结构。它表现为不同条件下制得的非晶氧化锆水合物的红外吸收谱在1700～1200cm-1水和羟基的弯曲振动吸收区出现1633、1551、1400和1340cm-1四个不同的羟基吸收峰。这表明样品中有三种不同近邻结构的羟基。根据实验结果我们提出了相应的非晶氧化锆水合物的近邻结构模型。造成这种结构差异的原因是制备过程中溶胶-凝胶反应的羟基浓度的不同。非晶态氧化锆水合物晶化后生成具有不同晶体结构的纳米氧化锆的主要原因是由于它们的不同近邻结构。%The structures of precursor of zirconia(a kind of amorphous hydrous zirconia prepared by sol-gel)were studied by infrared spectrum(IR),X-ray diffraction(XRD),differential thermal analysis(DTA)and weight loss(TG)in detail.The results indicated that there are three different near structures in amorphous hydrous zirconia.The different near structures can be found by infrared adsorption spectrum.In the band of 1700～1200cm-1,there are four absorption peaks for hydroxyl bending vibration.They are 1633,1551,1400 and 1340cm-1 respectively.We suggest that the 1633cm-1 belonged to physical adsorbed H2O,the 1564cm-1 belonged to coordinated H2O,the 1400cm-1 belonged to bridging hydroxyl group,and the 1340cm-1 belonged to coordinated hydroxyl group.It indicates that there are four different hydroxyl groups in these amorphous hydrous zirconia,and three different near structures.We suggested three modals for them.The cause of formation of these different structures is the difference of pH values in their preparation sol-gel reaction.The reason of formation different crystalline phases of zirconia from amorphous hydrous zirconia prepared in different pH value is the different near structures of them.