| Anatase TiO2 crystals usually expose with {101} facets rather than {001} facets. High recombination rate of photoinduced e-/h+ pairs and low quantum efficiency have greatly inhibited its photocatalytic activity. Moreover, TiO2 nanometerials have wide band gap?3.2 eV?, and can only utilize 35 % ultraviolet light in sunlight. Therefore, these disadvantages have greatly limite its practical application. In this work, TiO2 nanotubes used as precursor to react with Sr?OH?2 solution to fabricate heterojunction TiO2/SrTiO3 nanotube arrays?STO/TNs? exposed with antase TiO2 {001} facets. The photocatalytic activities of these desired composites can be largely enhanced under ultraviolet light. These samples were characterized by XRD, FE-SEM, FE-TEM, Raman spectra and XPS methods. The photoelectrochemical properties of TiO2/SrTiO3 composites were explored using a standard three-electrode mode. In order to study the influence of hydrothermal time on photo-electrocatalytic activity and photo-electrocatalytic stability of heterojunction STO/TNs, MB and Rh.B were used as target pollutants. Moreover, photo-electrocatalytic mechanism of heterojunction STO/TNs was further discussed.It is indicated that all STO/TNs expose with {001} high-reactive facets after 15 h hydrothermal reaction. More corrugated “gibbosity” crystals grains can be oberserved on the wall of samples and the wall thickness increases with increasing hydrothermal time. Photoelectrochemical experiments show that heterojunction STO/TNs prepared with 2 h?STNs-2? exhibites the best photoelectric response performance. The STNs-2 sample with optimum content of SrTiO3 form optimum heterojunction interface area on the surface of nanotubes and then inhibits the recombination of photo-excited e-/h+ pairs. The photoelectric degradation of MB and Rh.B show that STNs-2 conducts the best photoelectric degradation activity. Furthermore, STNs-2 achieves with 97 %99 % recovering yield, leading to good photostability. |
PDF Full Text Request