Preparation, characterization and photoactivity of hollow N, Co co-doped TiO2/SiO2 microspheres

Hollow N, Co co-doped TiO2/SiO2 microspheres (CNT) have been prepared by in-suit polymerization and chemical adsorption methods, using polystyrene microspheres (PS) as the templates, tetraethylorthosilicate (TEOS) and tetrabutyltitanate (TBOT) as precursors, triethylamine and cobaltous nitrate as N and Co sources, respectively. The resultant CNT was characterized and compared with TiO2/SiO2 (ST), N-doped TiO2/SiO2 (NT) and Co-doped TiO2/SiO2 (CT) which were synthesized by the same method. Characterization was performed by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). CNT was observed to be of hollow structure, with nanometer size, broad adsorption wavelength even to 600 nm and high photocatalytic activity. XPS analysis showed that a TiON bond was formed, while Co mainly existed in the form of CoOx–MO2 (M=Ti or Si). Co only served to broaden the visible light absorption scope. N and Co cooperated with each other and enhanced the photocatalytic activity.