AgO超细粉末的制备及银的价态变化研究

采用臭氧氧化硝酸银制备了高纯AgO超细粉末,利用差热法研究了AgO在不同温度下银的价态变化,同时采用X射线衍射、扫描电子显微镜和X射线光电子能谱等方法,分析了AgO粉末的物相、形貌以及不同温度加热后粉末中银的价态变化。结果表明,制备的AgO超细粉末属于单斜晶系,AgO粉末呈棒状。AgO超细粉末经过加热后,其颜色发生明显变化,且随着加热温度升高,粉末中AgO含量逐渐减少,Ag2O含量先增加后减少,Ag含量逐渐增加。当温度高于350℃时,AgO全部分解,46.49%转化为Ag2O,53.51%转化为Ag,至400℃时全部分解成银。XPS高分辨结果表明,不同粉末中氧的结构明显不同,反映出粉末中相的变化。

Preparation of Ultrafine AgO Powder and Silver Valence Change

High pure ultrafine AgO powder was synthesized by ozone oxidation of AgNO3. Silver valence change of AgO at different temperatures was determined by differential thermal analysis. AgO powder were also characterized by XRD, SEM and XPS to analyze the phase and morphology and the silver valence change of the powder heated at different temperatures. The results show that the crystal structure of the prepared ultrafine AgO powder belongs to monoclinic system and AgO particles are of virgulate shapes. The colour of ultrafine AgO powder changes obviously after heating. In the heating process, with increasing of the temperature, the content of AgO decreases gradually, the content of Ag2O increases firstly and then decreases and the content of Ag increases gradually. When the temperature exceeds 350 oC, AgO decompose completely, 46.49 % of which transforms into Ag2O and 53.51% transforms into Ag. And complete decomposition to Ag occurs at 400 oC. The XPS spectra of O1s on different powder surfaces are quite distinct, reflecting the lattice structure change of powder