Interface engineering of $\hbox {TiO}_{2}$@PANI nanostructures for efficient visible-light activation

Abstract

Core–shell-structured $\hbox {TiO}_{2}$@PANI composites were fabricated using negatively charged titanium glycolate (TG) precursor spheres, which were decorated using hydrochloric acid; subsequently, the uniform polyaniline (PANI) layer could be attached onto the surface of the polystyrene spheres by in situ chemical oxidative polymerization and finally, the resulting PANI-grafted TG were allowed to hydrolyse by treating the material with hot water. The TGs were transformed to porous $\hbox {TiO}_{2}$, leading to the formation of core–shell $\hbox {TiO}_{2}$@PANI composites. The resulting $\hbox {TiO}_{2}$@PANI composite photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet–visible diffuse reflection spectroscopy and photoluminescence spectroscopy. Significantly, the $\hbox {TiO}_{2}$@PANI composite photocatalysts exhibited dramatically enhanced photo-induced electron–hole separation efficiency, which was confirmed by the results of photocurrent measurements. PANI was dispersed uniformly over the porous $\hbox {TiO}_{2}$ surface with an intimate electronic contact on the interface to act cooperatively to achieve enhanced photocatalytic properties, indicating that core–shell $\hbox {TiO}_{2}$@PANI composite photocatalysts could be promising candidate catalysts under visible-light irradiation. The mechanism of enhancing photocatalytic activity was proposed on the basis of the experimental results and estimated energy band positions.