Synthesis And Photocatalytic Activity Of Ag/N Co-modified TiO₂ Hollow Nanorod Arrays

Nowadays, environmental issues and energy crisis have seriously hindered the human development, and the semiconductor photocatalysis is a promising method for solving the environmental and energy problems. Due to relatively high reactivity, low cost, chemical stability and non-toxicity, TiO₂ is often applied in the field of photocatalysis. However, the practical applications of TiO₂ catalyst has been suppressed, due to its wide band gap, low quantum yield.Recently, several attempts have been made to improve the photocatalytic activity,such as the control of TiO₂ nano-structure's morphology or size, metal / non-metal doping, noble metal deposition on the surface of TiO₂, coupled semiconductor, etc.This paper focues on two aspects as following:1.The control of TiO₂ hollow nanorod arrays'morphology TiO₂ hollow nanorod arrays were synthesized by liquid phase deposition (LPD) method using ZnO nanorod arrays as template. The factors ( n(Ti) / n(B) molar ratio, reaction temperature) effecting on the morphology of TiO₂ hollow nanorod arrays were discussed.2. TiO₂ nano-structure catalysts co-modified by both metal and non-metal elementsUsing ammonium hexafluorotitanate ((NH4)2TiF6) as law material, N doped TiO₂ hollow nanorod arrays were easily achieved by liquid phase deposition (LPD) method. The effect of Ag loading with different content on the photocatalytic activity was also discussed. The catalysts were characterized by Raman spectrum, FESEM, HRTEM, UV-vis absorption spectrum and XPS. The results suggest that AgNO3 additive in the precursor solutions not only can promote the anatase to rutile phase transition, but also influence the amount of N doping in the samples.The photocatalytic activity of all the samples was evaluated by photodegradation of methylene blue (MB) in aqueous solution. The results show that the photocatalytic degradation rate of Ag/N-THNA is 1.8 and 5.5 times higher than N-TANA under UV and Visble light irradiation, corresponding to the optimum Ag/Ti mole ratio of 0.02 and 0.026, respectively, which were attributed to the synergetic effect of Ag loading, N doping, and the multiphase structure (anatase/rutile).