Mesoporous architecture of TiO_2 microspheres via controlled template assisted route and their photoelectrochemical properties

摘要

Anatase titanium dioxide (TiO_2) microspheres were successfully synthesized via a controlled chemical route using carbon spheres as sacrificial templates. The morphology has been controlled by varying the deposition time of carbonaceous (c) spheres from 4 to 16 h with the interval of 4 h, which affect the size of TiO_2 spheres. The structural, morphological, optical, compositional and photoelectrochemical properties of the TiO_2 thin films were studied. X-ray diffraction (XRD) pattern confirms the formation of anatase TiO_2 with the tetragonal crystal structure. Field emission scanning electron microscopy analysis revealed that the synthesized anatase TiO_2 microspheres has average diameter of ~ 330-510 nm. The blueshift in optical absorption is observed due to Mie scattering. The indirect optical band gap energy of TiO_2 was varied over 3.05-3.16 eV, with the increase in deposition time. The HRTEM and SAED results show the polycrystalline nature of the sample which is in good agreement with the XRD. The anatase TiO_2 hollow spheres with mesoporous walls and high specific surface area i.e. 41 m~2 g~(-1) was obtained using this simple method. The films were photoelectro-chemically active with maximum current density 531 μA/ cm~2 under 100 mW/cm2 illuminations.