Shape-controlled Synthesis of Porous SnO_2 Nanostructures via Morphologically Conserved Transformation from SnC_2O_4 Precursor Approach

Porous SnO_2 nanostructures with controlled shapes were synthesized by a facile morphologically conserved transformation from Sn C_2O_4 precursor approach. Well-defined Sn C_2O_4 nanostructures can be obtained through a solution-based precipitation process at ambient conditions without any surfactant. The formation mechanism of such microstructures was tentatively proposed on the basis of intrinsic crystal structure and the reaction conditions. We found that the morphologies of precursor were well maintained while numerous pores were formed during the annealing process. The combined techniques of X-ray diffraction, nitrogen absorption–desorption, field emission scanning electron microscopy, and(high-resolution) transmission electron microscopy were used to characterize the as-prepared SnO_2 products. Moreover, cyclic voltammetry(CV) study shows that the shape of CV presents a current response like roughly rectangular mirror images with respect to the zero-current line without obvious redox peaks, which indicating an ideal capacitive behavior of the SnO_2 electrodes. The photoluminescence(PL) spectrum study suggests that the as-obtained porous SnO_2 nanostructures might have a large number of defects, vacancies of oxygen, and local lattice disorder at the interface, interior and exterior surfaces.