La-Cu-Mn系钙钛矿型复合氧化物的表面特征

Surface Characterization of La-Cu-Mn Perovskite-type Mixed Oxides

关键词:  钙钛矿  复合氧化物  X射线衍射(XRD)  X射线光电子能谱(XPS)

Key words:  perovskite  complex oxide  X-ray diffraction (XRD)  X-ray photoelection spectroscopy (XPS)

摘要:

采用以EDTA为配位剂的Sol-gel法制备La-Cu-Mn体系钙钛矿型复合氧化物,借助X射线衍射(XRD)、X射线光电子能谱(XPS)等手段对其表面的结构和性质进行表征。结果表明,Cu²⁺部分取代A位、B位或同时部分取代A位、B位将导致氧化物表面特征发生变化;部分取代A位的La³⁺比部分取代B位的Mn³⁺更有利于锰离子在表面富集,更能提高晶格氧的相对含量和阳离子缺陷的浓度,但对Mn³⁺含量的影响程度没有明显差异。

Abstract:

The La-Cu-Mn perovskite-type mixed oxides were prepared by the Sol-gel method using EDTA as complex agent,and characterized by X-ray diffraction(XRD) and X-ray photoelection spectroscopy(XPS).The XPS analysis reveals the characteristic changes resulting from the A-site substitutions,B-site substitutions or both substitutions of Cu in LaMn₃.A-site substitutions for La³⁺ is more beneficial to enhance the content of manganese ion on the surface,the relative value of lattice oxygen and the concentration of ion defect than B-site substitutions for Mn³⁺.But there is no marked difference in influence on Mn⁴⁺.