A Simple Two-Step Template Approach for Preparing Carbon-Doped Mesoporous TiO2 Hollow Microspheres

Carbon-doped TiO2 hollow microspheres with mesoporous structure were prepared by a simple two-step template method. The characterizations for the physicochemical properties of prepared samples under different calcination temperature were carried out by X-ray diffraction analysis, Brunauer-Emmett-Teller measurements, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectra. The carbon doping of TiO2 hollow spheres was easily achieved during the procedure for removal of carbon cores. With the doping of carbon, the absorption wavelength edge was expanded to the visible light region and the additional diffusive electronic states were observed on the valence band spectra of samples. C-doped TiO2 hollow spheres with rapid combustion at 500 degrees C exhibited the superior visible light photocatalytic activity for the degradation of toluene, 4.6 times greater than that of Degussa P25, due to its good crystallization, mesoporous structure composed by hollow sphere structure, and strong absorption in the visible light region. The procedure of carbon doping was discussed and the generating mechanism was proposed.