二元稀土钴酸盐合成及其电化学性能

摘要

用溶胶凝胶法合成了系列二元稀土钴酸盐,通过X-射线粉末衍射分析了晶体的结构.结果表明,获得的二元稀土钴酸盐具有钙钛矿结构,粉体晶粒尺寸在16.7～31.5nm之间.研究了碱性介质中的二元稀土钴酸盐的循环伏安性能,观察到Co(Ⅱ)/Co(Ⅲ)和Co(Ⅲ)/Co(Ⅳ)转化峰;研究了碱性介质中二元稀土钴酸盐对甲醇的催化氧化性能.研究表明,该系列稀土钴酸盐对甲醇具有电催化氧化作用,且随着钴酸盐所含的稀土元素的核电荷数增加,催化氧化性能下降;其中镧镨钴酸盐La0.5Pr0.5CoO3表现出较高的催化性能.%A series of binary rare earth cobaltites were synthesized by citrate sol-gel route and crystal structures were analyzed by X-ray diffraction spectra.Results show that the binary rare earth cobaltites possess perovskite structure,and that the particle sizes are between 16.7-31.5 nm.Both Co(Ⅱ)/Co(Ⅲ) transition and Co(Ⅲ)/Co(Ⅳ) transition are observed by cycle voltammetry in alkalescence medium.The results indicate that the binary rare earth cobaltites show electrocatalytic activities on the oxidation of methanol,and that electrocatalytic activities of the binary rare earth cobaltites decrease when increasing the nuclear charge number of rare earth.The results also display that cobahite La0.sPr0.5CoO3 shows higher catalytic activities than other binary rare earth cobaltites.