Ce_(0.5)Zr_(0.5)O_2固溶体的原位拉曼光谱

IN SITU RAMAN SPECTROSCOPIC RESEARCH OF Ce 0.5 Zr 0.5 O 2 SOLID SOLUTION

控制合成条件以湿化学法制备了ＣｅＺｒＯ（ｎ（Ｃｅ）／ｎ（Ｚｒ）＝１）固溶体．ＸＲＤ结果证实催化剂前体经９２３Ｋ焙烧后可获得立方相Ｃｅ０．５Ｚｒ０．５Ｏ２固溶体．ＴＥＭ观察到固溶体颗粒大小均一（ｄ＝１１ｎｍ）、分散，呈纤毛状．在氧化和还原气氛条件下分别对固溶体进行了原位拉曼光谱研究．结果表明，除４５０～４７０ｃｍ－１处出现面心立方晶格Ｆ２ｇ拉曼活性模式对应的强拉曼谱峰外，２９０～３２０ｃｍ－１，５７０～６２０ｃｍ－１，７７０～７９０ｃｍ－１和１１６０～１１９０ｃｍ－１处分别出现弱峰或弱肩峰，各谱峰随样品处理条件改变而有不同的变化情况；固溶体的晶体结构会因氧化还原气氛以及温度等外界条件的不同发生畸变，但基本上保持为萤石构型．

Ce 0.5 Zr 0.5 O 2 solid solution was prepared by wet chemical preparation method under controlled conditions. The crystal structure of the solid solution after calcination at 923 K is face centered cubic (fluorite type) verified by XRD. The solid grain is super micro powder of fiber like. Diameter of the solid solution particle is 11 nm. In situ Raman spectra of the catalyst at 323～923 K in oxygen or hydrogen atmosphere give the strong Raman peaks at 450～470 cm -1 owing to the F 2g Raman active mode characteristic of fluorite structure. The weak Raman peaks at 290～320 cm -1 , 570～620 cm -1 , 770～790 cm -1 and 1160～1190 cm -1 are also given. The Raman peaks have different changes according to the alteration of environmental conditions, such as redox atmosphere and temperature. The Raman peaks reveal that the crystal structure is deformed in the lattice by changing the external conditions, but at the same time the fluorite structure keeps unchanged.