氧化共沉淀法制备Ce_(0.65)Zr_(0.25)Y_(0.1)O_(1.95)的结构转化过程

Structure Evolution Process of Ce_(0.65)Zr_(0.25)Y_(0.1)O_(1.95) Prepared by Oxidation-Coprecipitation Method

以氨水和碳酸铵为沉淀剂,采用氧化-共沉淀法制备了Ce0.65Zr0.25Y0.1O1.95复合氧化物,并对不同处理温度下制备的样品用热重-差示扫描分析(TG-DSC)、傅里叶变换红外(FT-IR)光谱、X射线衍射(XRD)和表面分析仪(BET)等进行了表征.结果表明,共沉淀法得到的沉淀物同时含有羟基和羧基,随着焙烧温度的升高,分别在100-170℃、250-300℃和420-500℃温度范围内先后发生脱水、脱羟基和脱羧基反应,在此过程中固溶体逐渐形成.提出了由沉淀物转变为Ce0.65Zr0.25Y0.1O1.95复合氧化物的结构转变模型.

Ce0.65Zr0.25Y0.1O1.95 oxides were prepared by oxidation-coprecipitation method using ammonia and salvolatile as precipitators. The as-prepared samples were thermally treated at different temperatures and characterized by thermogravimetry-differential scanning calorimetry （TG-DSC）, Fourier transform-infrared （FT-IR） spectrometry, X-ray diffraction （XRD）, and specific surface area measurements （BET）. The results showed that the hydroxyl and carboxyl groups coexisted in the precipitate and a perfect solid solution was gradually formed with an increase in calcination temperature. The physisorbed water was lost from 100 to 170℃, hydroxyl groups were removed from 250 to 300℃, and the carboxyl groups were eliminated from 420 to 500℃. A structure model was further proposed to understand the Ce0.65Zr0.25Y0.1O1.95 structure evolution process in depth.