Nan Jiang,Yi Du,Shiquan Liu,Minxing Du,Yibing Feng,Yang Liu
Different kinds of oriented TiO 2 nanorod arrays have been actively pursuing in recent years, however, these fabrications relied on the substrates, such as fluorine-doped tin oxide glass (FTO), silicon wafer or other semiconductor precursor layer. Herein, a stable Ti 3+ and oxygen vacancies doped blue TiO 2 flakes composed of oriented nanorod arrays were synthesized using a facile hydrothermal treatment in diluted hydrochloric acid solution. Such centimeter-scale flake-like TiO 2 product was obtained without any substrate. Since Ti 3+ self-doped and/or oxygen vacancies TiO 2 could extend the absorption range of TiO 2 to visible light region, the blue TiO 2 sample exhibited excellent photocatalytic activity under visible light irradiation (photocatalytic degradation efficiency can nearly reach up to 100% within 60 min).
Baolin Yan,Juan Zhou,Xiaoyu Liang,Kainan Song,Xintai Su
The production of H 2 by photocatalytic water splitting has become a promising approach for clean, economical, and renewable evolution of H 2 by using solar energy. In spite of tremendous efforts, the present challenge for materials scientists is to build a highly active photocatalytic system with high efficiency and low cost. Here we report a facile method for the preparation of TiO 2 /C nano-flakes, which was used as an efficient visible-light photocatalyst for H 2 evolution. This composite material was prepared by using a phase-transfer strategy combined with salt-template calcination treatment. The results showed that anatase TiO 2 nanoparticles with the diameter of ∼10 nm were uniformly dispersed on the carbon nano-flakes. In addition, the samples prepared at 600 °C (denoted as T600) endowed a larger surface area of 196 m 2 g −1 and higher light absorption, resulting in enhanced photocatalytic activity. Further, the T600 product reached a high H 2 production rate of 57.2 μmol h −1 under visible-light irradiation. This unusual photocatalytic activity arose from the positive synergetic effect between the TiO 2 and carbon in this hybrid catalyst. This work highlights the potential of TiO 2 /C nano-flakes in the field of photocatalytic H 2 evolution under visible-light irradiation.
Zhiwei Li,Guodong Jiang,Zihao Zhang,Ye Wu,Yinhui Han
Photocatalysts Phosphorus-Doped g-C 3 N 4 (P(x%)-g-C 3 N 4 ) were successfully prepared by a two-step method using melamine and phosphonitrilic chloride trimer (Cl 6 N 3 P 3 ). Then, the Phosphorus-doped g-C 3 N 4 sheets coated with TiO 2 nanoparticles (P(x%)-g-C 3 N 4 /TiO 2 ) were prepared by solvent-thermal method. The as-prepared P(x%)-g-C 3 N 4 /TiO 2 composites showed enhanced light absorption and photocatalytic properties in visible light region. The morphology of g-C 3 N 4 nanosheets and square flake TiO 2 nanoparticles were analyzed with field emission scanning electron microscopy (FESEM) and scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) proved that the P-C bonds were generated in P(x%)-g-C 3 N 4 . Photoluminescence (PL) spectra revealed that the phosphorus doping improved the separation and transfer of photogenerated electrons and holes in P(x%)-g-C 3 N 4 , UV–vis diffuse reflectance spectra (UV-vis DRS) indicated that the P(x%)-g-C 3 N 4 /TiO 2 heterostructure enhanced the absorption of visible light. The photocatalytic activity of the P(x%)-g-C 3 N 4 was evaluated by photocatalytic degradation of Methyl Blue (MB) under visible light irradiation. The result indicated that the P(0.1%)-g-C 3 N 4 /TiO 2 composite present considerably high photocatalytic degradation activities on MB, and the degradation of MB by P(0.1%)-g-C 3 N 4 /TiO 2 were 5.1 times and 2.9 times as high as that of g-C 3 N 4 and P25, respectively. At the end of article, a possible photocatalytic mechanism was discussed based on the experimental results.
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