Synthesis and photocatalytic activity of polyaniline-TiO2 composites with bionic nanopapilla structure

Polyaniline (PANI)-TiO2 nanocomposites possessing both nano and microscale structures were prepared through a facile hydrothermal route in the presence of PANI. The nanopapilla particles were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectra, X-ray diffraction, FTIR spectra, UV-Vis spectroscopy, and N-2 adsorption analysis, etc. The results show that the composites possess both nano and microscale structures. The TiO2 nanorods are dispersed on PANI with one end fixed to the surface. The photocatalytic properties of the powders were verified by the photodegradation of gaseous acetone under UV (lambda = 254 nm) and visible-light irradiation (lambda > 400 nm). In fact, the photocatalytic effects exhibited by the composite particles were superior to that of pure TiO2 and P25 samples. This excellent behavior is attributed to the structural features of PANI-TiO2 microspheres and the synergistic effect between PANI and TiO2 which facilitates a larger amount of surface active sites. This in turn causes a faster charge separation and slower charge recombination which results in a more efficient decomposition of gaseous pollutants.