Role of Microstructure and Spectrum Features on the Catalysis Effect of Ce1-x(Nd0.5Eu0.5)xO2-d Solid Solutions

分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》

ZHANG Guo-Fang HOU Zhong-Hui ZHAI Ting-Ting XV Jian-Yi ZHANG Yang-Huan

摘要： Nanosized Ce1-x(Nd0.5Eu0.5)xO2-d solid solutions (x = 0.00～0.20) were synthesized by means of hydrothermal method. Then the solid solutions were ball milled with Mg2Ni and Ni powders for 20 h to get the Mg2Ni–Ni–5 mol% Ce1-x(Nd0.5Eu0.5)xO2-d composites. The structures and spectrum characteristics of the Ce1-x(Nd0.5Eu0.5)xO2-d solid solutions catalysts were analyzed systemically. XRD results showed that the doped samples exhibited single phase of CeO2 fluorite structure. The cell parameters and cell volumes were increased with increasing the doped content. Raman spectrum revealed that the peak position of F2g mode shift to higher wavenumbers and the peak corresponding to oxygen vacancies were observed distinctly for the doped samples. UV-Vis technique indicated that the absorption peaks of Eu3+ and Nd3+ ions appeared; the bandgap energy was decreased linearly. The electrochemical and kinetic properties of the Mg2Ni–Ni–5 mol% Ce1-x(Nd0.5Eu0.5)xO2-d composites were measured. The maximum discharge capacity was increased from 722.3 mAh/g for x = 0.00 to 819.7 mAh/g for x = 0.16, and the cycle stability S20 increased from 25.0% (x = 0.00) to 42.2% (x = 0.20). The kinetic measurement proved that the catalytic activity of composite surfaces and the hydrogen diffusion rate were improved for the composites with doped catalysts, especially for the composites with x = 0.16 and x = 0.20. The catalysis mechanism was analyzed from the point of microstructure and spectrum features of the Ce1-x(Nd0.5Eu0.5)xO2-d solid solutions.

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