Structural characterization, phase analysis and electrochemical hydrogen storage studies on new pyrochlore SmRETi2O7 (RE = Dy, Ho, and Yb) microstructures

A modified solid-state method was used to synthesize new SmRETi2O7 pyrochlores. The new samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), Fourier transform infrared (FT-IR) and Raman spectroscopy. Qualitative and quantitative analyses were done by MAUD software to obtain crystallographic parameters. Based on the results, the crystal system of the new SmRETi2O7 pyrochlores was cubic with Fd3m space group. A slight shift in the Bragg positions was observed which was related to the cationic radii of the rare earth cations. The correlation between the structural parameters and the crystallographic data was also done. Besides, the electrochemical hydrogen storage (EHS) capacity of these pyrochlores were investigated. The holmium-containing oxide structure (SmHoTi2O7) compared to other samples exhibited a higher discharge capacity, about 1340 mAh/g. The results of EHS studies well correlated with the crystallographic data.