Synthesis and photocatalytic properties of SiO2/TiO2 nanofibers using templates of TEMPO-oxidized cellulose nanofibers

SiO2/TiO2 nanofibers were fabricated using TEMPO-oxidized cellulose nanofibers (TOCN) as templates. SiO2 and/or TiO2 deposition onto the surface of TOCN was achieved by the hydrolysis and condensation reactions of two types of silicon alkoxide and a titanium alkoxide. After the combustion of TOCN templates, SiO2/TiO2 nanofibers with the high specific surface area of 158 m(2)/g that were the composite nanofibers of TiO2 and SiO2 were obtained. The SiO2/TiO2 nanofibers have a diameter of around 8 nm and consist of a core/shell structure derived from the sequential deposition of SiO2 and TiO2. The structures of SiO2 core and TiO2 shell consist of amorphous and anatase nanocrystals, respectively. We confirmed that the synthesized SiO2/TiO2 nanofibers exhibit higher photocatalytic activity for degrading the cationic pollutant of methylene blue (MB) than conventional porous TiO2 particles with a similar specific surface area. The mechanisms for the enhanced MB degradation of the SiO2/TiO2 nanofibers are discussed.