Synthesis, characterization, and photocatalytic properties of ZnO/(La,Sr)CoO3 composite nanorod arrays

ZnO/(La, Sr) CoO3 (ZnO/LSCO) core-shell composite nanorod arrays have been successfully synthesized by a sequential combination process of a hydrothermal synthesis followed by a pulsed laser deposition (PLD) process (or a colloidal deposition process). Compared to the colloidal deposition process, PLD produces a more uniform and efficient deposition of continuous and mesoporous LSCO thin films onto ZnO nanorod arrays. During the PLD process, the deposited film uniformity was found to be dependent on the nanorod diameter, array density, and thus specific surface area of the nanorod arrays, in addition to the PLD deposition parameters. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to investigate the surface morphologies and orientations of the composite nanorod arrays. With densely packed ZnO nanorod arrays as a unique support structure, the mesoporous LSCO thin film coated on top exhibited better photocatalytic properties than ZnO nanorod arrays and LSCO thin films deposited on flat Si substrates. With optimization of the structure, dimensionality, packing density, as well as the composition and interface structure, these unique composite nanoarchitectures could be a promising class of photocatalyst candidates for organic molecule degradation.