Synthesis and characterization of silica-capped titania nanorods: An enhanced photocatalyst

摘要

A new one-pot synthesis route to produce silica nano-layer capped titania (SiO_2TiO_2) nanorods,a TiO_2-based nanocomposite photocatalyst,has been developed by means of a non-aqueous solution method.The whole of the TiO_2 rod is covered with a heterogeneous SiO_2 layer except at the two ends.The simultaneous development of a SiO_2 nano-layer onto an evolutional TiO_2 nanorod highly depends on the mole ratio of the starting reagents.Additionally,in the study of the adsorption of rhodamine-6G (R-6G) by SiO_2TiO_2 nanorods,the spectra data confirms that the SiO_2 nano-layer can noticeably accumulate the adsorbed concentration of R-6G on the surface of SiO_2TiO_2 nanorods,which offers a critical example to explain why the SiO_2 layer can enhance the photodecomposition rates of TiO_2 based photocatalysts.Under UV irradiation (lambda= 254 nm),the photodecomposition rates of R-6G for the SiO_2TiO_2 samples (0.0242 min~(-1)) are about 3-6 times faster than that of the particulate TiO_2 (4.0 x 10~(-3) min~(-1)) and SiO_2/TiO_2 (=25/75) (6.7 x 10~(-3) min~(-1)) xerogel photocatalysts.The process of uniformly growing SiO_2 nano-layer onto TiO_2 based nanocomposite photocatalyst also demonstrates that the existence of SiO_2 layer is beneficial for the photocatalysis efficiency but the improvement of photocatalysis efficiency is not proportional to the thickness of SiO_2 layer.