Abstract
Nano-composites of lanthanum-samarium oxide (LaSmO2) were prepared in the absence and presence of graphene oxide (GO) and characterized as an effective electrode material for hydrogen fuel cells. X-ray and scanning electron microscope investigations revealed grain sizes of 8 nm for LaSmO2 and 12 nm for GO-LaSmO2 composites. The x-ray diffraction pattern showed sharp peaks, indicating a well-crystallized phase indexable to a rhombohedral structure with space group R 3 (C) , and their structural refinement performed in the hexagonal mode. The ionic conductivity of LaSmO2 was found to be 4.12 x 10(-5) S/cm, while in the presence of GO it was enhanced to 5.32 x 10(-5) S/cm. The mechanism of conduction in the proposed nano-materials was investigated based on frequency exponent S. The values of S were observed to decrease with increasing temperature. This result was found to be in good agreement with the correlated barrier hopping (CBH) model. The present work revealed GO to be a conductivity enhancer that caused the GO-LaSmO2 composite to be an effective electrode material for hydrogen fuel cells.