Fabrication of porous TiO2 nanofiber and its photocatalytic activity

Porous TiO2-based nanofiber was fabricated via a combined electrospinning and alkali-dissolution method. TiO2/SiO2 composite nanofiber was firstly prepared by electrospinning and sintering, and then silica was leached out with alkaline solution from the bulk of TiO2/SiO2 composite nanofiber to produce porous microstructure. The thermal decomposition and phase structure of the composite nanofiber precursor was investigated with TG/DSC and XRD, and optimal sintering temperature was obtained. SEM-EDX and FT-IR characterization show that most silica can be dissolved out from the composite nanofiber and thus porous nanofiber with excellent microstructure can be spontaneously formed. The effect of composite nanofiber composition on porous microstructure was studied, and it is found that the composite nanofiber with 20wt% silica can produce better porous microstructure compared to those with 10wt% and 30wt% silica. Meanwhile, porous TiO2 nanofiber with 20wt% silica shows higher degradation efficiency to Congo Red.