Fabrication of Barbed-Shaped SnO@SnO2 Core/Shell Nanowires

The interest in core/shell nanowires (Nws) is stimulated by the importance of fabricating materials possessing unique magnetic, catalytic, or optical properties relative to ones of their bulk parents. Here, the fabrication of a novel design of core−shell SnO@SnO2 Nws via heat treatment of Sn Nws, fully encapsulated inside the pores of alumina matrix, is demonstrated. Under this scenario, densely packed arrays of barbed-shaped Nws, possessing extremely high surface areas, have been fabricated. 119Sn Mossbauer effect spectroscopy, high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and X-ray diffraction spectroscopy (XRD) were used to study the morphology and composition of the end-products. In addition, electron energy-loss spectroscopy (EELS) was successfully applied here to detect the ionization edges of tin and oxygen in the core and shell part of single Nw.