化学学报 ›› 2000, Vol. 58 ›› Issue (7): 925-930. 上一篇    

研究论文

铬在纳米晶氧化铁中的掺杂研究

陈林深;吕光烈;许裕生;陈诵英   

  1. 浙江大学分析测试中心西溪分中心;苏州大学物理系;浙江大学催化研究所
  • 发布日期:2000-07-15

Study on the doping mechanism of chromium in nano-sized iron oxide

Chen Linshen;Lu Guanglie;Xu Yusheng;Chen Songying   

  • Published:2000-07-15

Fe^3^+(Cr^3^+)/Fe^2^+混合离子(M^3^+/M^2^+原子比为2:1)共沉淀法制备的Cr~2O~3掺杂量O~14%(质量分数)系列纳米氧化铁,XRDRietveld分析表明全是晶态γ-Fe~2O~3和非晶Fe~2O~3的混合物。非晶丰度范围为21.72%~48.6%。Mossbauer谱分析发现,掺杂量少于2%(质量分数)的氧化铁,晶态和非晶态均是磁性六线谱,大于2%(质量分数)后,另出现强度随掺杂量增加线性递增的超顺磁二线谱。共沉淀过程中,Fe^3^+为主夹杂定量Cr^3^+的Fe^3^+水合配合物网络与Cr^3^+为主夹杂定量Fe^3^+的Cr^3^+水合配合物网络,是形成磁性氧化铁和非晶非磁氧化铁的基础,后者镶嵌在前者中间,阻碍其晶化和晶粒长大,自身形成非晶非磁含铬氧化铁。

关键词: 氧化铬, 氧化铁, 纳米相材料, 掺杂, 穆斯堡尔谱法

Nano-sized Fe~2O~3 containing 0~14% (mass fraction) Cr~2O~3 was prepared by coprecipitation method using Fe^3^+ (Cr^3^+)/Fe^2^+ mixed ions (with the ions ratio= 2 : 1). XRD Rietveld analysis showed that such Fe~2O~3 was a mixture of crystalline γ-Fe~2O~3 and amorphous Fe~2O~3. The abundance of amorphous Fe~2O~3 ranged from 21.72% to 48. 60%. When the amount of doping Cr~2O~3 was less than 2.4%, the Mossbauer spectra of either the crystalline or amorphous Fe~2O~3 samples were all sextets. If Cr~2O~3 was more than 2.4%, there appearred a superpara-magnetic doublet whose intensity increases linearly with the concentration of Cr~2O~3 . During coprecipitating, there existed two hydrous complexes, one was Fe^3^+ hydrous complexes mixed with a small amount of Cr^3^+, another was Cr^3^+ hydrous complexes mixed with Fe^3^+. These hydrous complexes formed nano-sized magnetic and non-magnetic Fe~2O~3 respectively. The later hydrous complexes mixed with the former, hinderd crystal forming and growth.

Key words: CHROMIUM OXIDE, IRON OXIDE, NANOPHASE MATERIALS, DOPE, MOSSBAUER SPECTROMETRY

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