Mesoporous TiO2 nanofibers with controllable Au loadings for catalytic reduction of 4-nitrophenol

The Au/TiO2 hybrid nanofibers composed of mesoporous TiO2 nanofibers and Au nanoparticles were synchronously fabricated by integrating a facile electrospinning technique and subsequent annealing in air. The Au loading content in the hybrid nanofibers was regulated by varying the dosage of chlorauric acid added in the precursor solution. The compositions, microstructures and optical response properties of the Au/TiO2 hybrid nanofibers were characterized. The UV-vis spectra of the as-prepared hybrid fibers reveal two absorption bands belonging to the band gap absorption of TiO2 and the surface plasmon resonance (SPR) of Au nanoparticles. For the catalytic reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride, the apparent reaction rate constant is raised but TOF value of the catalyst decreases, as the Au loading amount in the hybrid fibers increases. This is because the Au nanoparticles with smaller sizes have higher total surface areas at the same weight and therefore show higher catalytic activity. This method for producing Au/TiO2 hybrid nanofibers is versatile and can be extended to the fabrication of other hybrid nanofibers composed of various noble metal nanoparticles and other mesoporous metal oxide nanofibers, designing of highly efficient catalysts for more important chemical reactions.