【摘要】 用穆斯堡尔谱学,X射线衍射和激光喇曼光谱研究了EU₂O₃在非晶Al₂O₃上的固体-固体表面吸附。没有观察到Eu₂O₃的X射线衍射峰。随着Eu₂O₃含量的增加,同质异能移和线宽持续增加并趋近体相Eu₂O₃值。激光喇曼光谱表明Eu₂O₃含量为18.7wt.％时,出现表征二维含铕表面氧物种998cm^-1和1051cm^-1的两个弱振动峰。当Eu₂O₃含量增加到36.5wt.％时,出现表面氧物种的1068cm^-1峰和Eu₂₃的342cm^-1特征峰。比较了Eu₂O₃在非晶Al₂O₃和在其他载体表面的分散情况。同质异能移的变化缘于载体具有不同的电负性。研究结果表明,存在载体对分散在载体表面的Eu₂O₃结构形成的诱导效应。更多还原

【Abstract】 Solid-solid surface adsorption of Eu2O3 of amorphous A12O3 was investigated by Mossbauer Spectroscopy,X-ray diffraction analysis and a Laser Raman Spectra. No X-ray diffraction peak of crystalline Eu2O3 can be found for all samples studied. With increasing Eu2O3 content the isomer shift and line width increase continously and gradually approach those of bulk Eu2O3. The Laser Raman Spectra show that two peaks at 998 and 1051 cm-1assigned to two-dimensional surface europium-oxygen species appear at Eu2O3 content of 18. 7 wt. %. The peak at 1068 cm-1 due to the surface species and another peak at 342 cm-1 due to crystalline Eu2O3 content start to appear for the sample with Eu2O3 content of 36. 5 wt. %. The dispersity of Eu2O3 on the surface of amorphous A12O3 was compared with that of r-A12O3, g -A12O3 and SiO2 gel. The change of isomer shift for the different supports results from their distinct electronegativity. The results of these studies indicate that the structure of Eu2O3 dispersed onto the support surface depends on the structure of support and that there is an inductive effect of support on the structure of the Eu2O3.更多还原