| TiO2hollow spheres (HSs) were synthetized with a template method. We firstlyobtained SiO2core spheres through the hydrolysis of tetraethyl orthosilicate (TEOS)and then coated the SiO2spheres with TiO2using titanium tert-butoxide (TBOT) as aprecursor. Then we coated the SiO2@TiO2with another SiO2layer to formSiO2@TiO2@SiO2nanocomposites. The external SiO2layer makes theamorphous-anatase transformation possible, in the meanwhile restrains the growth ofanatase into large particles, inhibiting the phase transformation from anatase to rutileat high temperatures (subsequently reaching800oC condition). Through calcinationand etching of SiO2, we obtained the TiO2hollow spheres. These TiO2HSs werethermally treated with NH3for nitrogen doping and impregnated with AgNO3todeposite Ag nanoparticles on TiO2surface (Ag-N/TiO2). Methyl blue was used as amodel pollutant to evaluate the performance of photocatalyst activities undervisible-light irradiation. We noted that the Ag-N/TiO2hollow spheres nanostructurepossessed high activities and were very stable even at high temperature, which couldbe attributed to the advantage of high photo-harvesting efficiency and the unique shellstructure. This paper also describes the synthesis of TiO2hollow spheres (HSs)modified via nitrogen doping and silver loading (Ag-N-TiO2) with particle diametersof~100nm The specific surface area of the Ag-N-TiO2was up to147m2g1and thisstructure is stable upon high temperature treatment. Ag-N-TiO2exhibited excellentphotocatalytic activity for degradation of dye compoun under visible light irradiation(≥410nm) due to their larger surface area and controlled morphology compared withpreviously reported N-doped TiO2fine particles (e.g., N-P25) Finally, this paperdescribes a method for facile synthesis of mesoporous cuplike anatase TiO2nanocrystals. The novel cuplike morphology of TiO2nanomaterial shows remarkablyhigh photocatalytic activity for degradation of methylene blue under visible lightirradiation. |
PDF Full Text Request