Polarization-enhanced photoelectrochemical properties of BaTiO₃/BaTiO_3-x/CdS heterostructure nanocubes

With the aim of improving the photocatalytic activity for water splitting, novel core-shell-structured crystalline-BaTiO₃/amorphous-BaTiO_3-x/crystalline-CdS composite nanocubes are prepared by a facile two-step synthesis approach. Basic characterization techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy are carried out on the as-prepared composite nanocubes in order to confirm the quality of their crystal structure, morphology and chemical components correspondingly. UV-Vis-NIR measurements of the as-prepared composite nanocubes validate the presence of extended visible-light absorbance due to oxygen-deficient BaTiO_3-x. Photoelectrochemical tests are carried out on the as-prepared nanocomposite films that are coated directly on indium tin oxide (ITO) glass substrates. The as-prepared composite nanocubes show a photocurrent density of 100 μA cm^-2 without electric field poling, whereas they show about 200 μA cm^-2 with an electric field poling of 18.8 kV cm^-1. This study suggests that the photoelectrochemical performance is highest in our prepared BaTiO₃/BaTiO_3-x/CdS composite film compared to the pure BaTiO₃, CdS and BaTiO₃/BaTiO_3-x films, and it may offer a new potential route for designing cost-effective, highly stable and efficient photocatalysts.