Hierarchical TiO2 nanosheet‐assembled nanotubes with dual electron sink functional sites for efficient photocatalytic degradation of rhodamine B

Abstract

A novel Pt–TiO2/Ag nanotube photocatalyst has been synthesized successfully via a facile method. TiO2 nanotubes are assembled with numerous ultrathin TiO2 nanosheets and show a highly open structure. The gaps between adjacent TiO2 nanosheets can serve as channels for the access of reactants, accelerating the mass transfer process. During the fabrication process of the Pt–TiO2/Ag nanotube photocatalyst, high‐quality Pt–SiO2 nanotubes are synthesized first with the structure‐directing effect of polyvinylpyrrolidone. Then a TiO2 layer is coated on the outside surface of the silica nanotubes. The introduced titanium species can be converted into TiO2 nanosheet structure during the subsequent hydrothermal treatment, gradually constructing nanosheet‐assembled nanotubes. Lastly, after the introduction of another electron sink function site of Ag through UV irradiation, the Pt–TiO2/Ag nanotube photocatalyst with dual electron sink functional sites is obtained. The specially doped Pt and Ag NPs can simultaneously inhibit the recombination process of photogenerated charge carriers and increase light utilization efficiency. Therefore, the as‐synthesized Pt–TiO2/Ag nanotube catalyst exhibits a high photocatalytic degradation performance for rhodamine B of 0.2 min−1, which is about 3.2 and 5.3 times as high as that of Pt–TiO2 and TiO2 nanotubes because of the enhanced charge carrier separation efficiency. Furthermore, in the unique nanoarchitecture, the nanotubes are assembled with numerous ultrathin TiO2 nanosheets, which can absorb abundant active species and dye molecules for photocatalytic reaction. On the basis of experimental results, a possible rhodamine B degradation mechanism is proposed to explain the excellent photocatalytic efficiency of the Pt–TiO2/Ag nanotube photocatalyst.