| One-dimensional hydrogen titanate and titanate nanomaterials find potential applications in the various fields of photocatalysis, dye-sensitized solar cells, lithium-ion battery electrodes, gas sensors, and hydrogen storage. It is of interest to develop a preparation method which has the advantages of simple equipmental requirements, mild reaction condtions, simple operations, and being applicable to various substrates. In this paper, hydrogen titanate nanowire film (HTNF) was deposited on the substrate of a stainless steel mesh. The effects of various processing parameters on the morphology of the film were studied and efforts were also made to achieve the one-pot deposition of HTNF on the stainless steel mesh with a large surface of ca.960 cm2. The photocatalytic activity was evaluated by photodegradation of rhodamine B in water with and without the additives of H2O2 or H2SO4. The structure and photocatalytic activity of the HTNF was regulated by the subsequent hot water treatment and heat treatment in air. The photocatalytic activity of a large area film was evaluated by photodegradation of a variety of organic compounds of rhodamine B, sulfosalicylic acid, and phenol in deionized water and tap water.Follows are the main conclusions obtained:1. The preparation of HTNF:HTNF was deposited on stainless steel mesh with a sol-gel TiO2 seed layer by immersing them in a H2O2 solution including C3H6N6 and HNO3 at 80 ℃. Sponge Ti particles were added to provide the Ti(Ⅳ) source. Homogeneous HTNF with high density was achieved using the processing parameters as follows:6-48 h reaction time,20-30 wt.% H2O2,0.385-1.93 g/L C3H6N6, and 11.5-19.2 mL/L HNO3. The optimized technique to fabricate HTNF was of good reproducibility and was capable of depositing HTNF on large area stainless steel mesh (35 cm in diameter), in case that the seed layer was deposited by repeating twice the sol-gel dip-coating procedure.2. Photocatalytic performance of HTNF and its improvements:The HTNF with a size of 2.5×2.5 cm2 in area was used to assist photodegradation of 50 mL 0.005 mM rhodamine B under UV illumination. The degradation rate is 82.1% after 2 h’s illumination, but with poor cycling performance. There was an 18.9% increase in the degradation rate when 5×10-2 M H2SO4 was added in the solution. When 20 ppm H2O2 was added, there was a 17.3% increase in the degradation rate, which then decreased with the additive of more H2O2.3. The regulation of the structure and photocatalytic activity of the HTNF: The HTNF subjected to a subsequent pure water treatment at 80 ℃ for 48 h transformed to TiO2 mainly consisted of anatase, which exhibited the best photocatalytic properties. Increasing the hot water treatment temperature to 90 ℃ accelerated the transformation procedure of the hydrogen titanate nanwires. When calcinated in air at 200 ℃ for 1 h, no remarkable change in both the morphology and the crystal structure of the HTNF can be discerned; however, the photocatalytic property reduced significantly. The calcination of HTNF at 550 ℃ for 1 h resulted in anatase TiO2 nanowires with chain-like stacked nanoparticles, which exhibited a good cycle performance when used to assist the degradation of organic compounds in water, with the additive of 20 ppm H2O2. |
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