Preparation of In2O3@TiO2 core-shell spherical nanocomposites with the enhanced photocatalytic activity under solar light irradiation

Abstract

In this study, we demonstrate In2O3@TiO2 core-shell spherical nanocomposites prepared by hydrothermal method and sol-gel coating method. The In2O3 particles show quite a uniform part icle size (∼200 nm in diameter) and smooth surface. Porous TiO2 polycrystalline is coated on the surface of In2O3 nanospheres as a shell. The thickness of the shell can be controlled by adjusting the molar rat ios of In to Ti. UV-Vis spectra indicate that the adsorption peaks of pure In2O3 and TiO2 nanospheres are located at 323 and 319 nm, respectively. The surface coating of TiO2 canmake the adsorption of nanocomposites shift to the long wavelength to ∼340 nm. The photocatalytic activities of the pure In2O3, TiO2, and the nanocomposites obtained with different molar rat ios of In to Ti were evaluated by measurement of the degradation concentration of 30 ppm methylene blue (MB). The results show that the nanocomposites show higher photocatalytic performance than the pure oxides. The ratio at 1:10 exhibits the highest reaction rate constant (0.0152 min−1), similar to other nanocomposites but higher than pure In2O3 nanospheres (0.0069 min−1) and TiO2 (0.0058 min−1). This can be attributed to the large surface and tuned band energy structure for enhanced visible light absorption and the effective charge separation at the heterojunction of In 2O3 and TiO2. These findings may benefits to the new developed core-shell material as photocatalysts with enhanced efficiency for environmental applications.