Self-assembly of efficient flower-like Bi2SiO5 photocatalyst through Pt modification

The flower-like Pt/Bi2SiO5 photocatalysts was successfully synthesized via a hydrothermal-photoreduction method and applied for removing 17 alpha-ethynylestradiol (EE2). Firstly, the Bi2SiO5 nanosheets was prepared by hydrothermal method, marked as BSO. Then, the flower-like Pt/BSO was synthesized with H2PtCl6 as the platinum source, methanol as electron donor and the 300 W mercury lamp as light source to restore Pt. In the process of photoreduction, H2PtCl6 was not only used as Pt resources, but also cause the BSO nanosheets assembled into flower-like structures. In addition, with introduction of Pt, the band gap width become narrower. Moreover, the amount of platinum can affect the photocatalytic activity. When the dosage of H2PtCl6 solution is 0.2 mL, the prepared optimal material was marked as 0.2 Pt/BSO. The total degradation efficiency of EE2 reached 95.6% after only 8 min of UV-light irradiation over 0.2 Pt/BSO, and the reaction rate constant were 46.16, 8.0 and 5.82 times higher than EE2 photolysis, P25 and BSO nanosheets, respectively. The physical and chemical properties of different photocatalysts were characterized by XRD, XPS, SEM, TEM, UV-vis DRS and PL techniques. The effects of pH value for removing EE2 in water was investigated. The possible photocatalytic mechanism was proposed on the basis of trapping photocatalytic experiments. 0.2 Pt/BSO photocatalyst also depicted high stability and durability during three successive cycles. Results in this work provide new insights into improving the photocatalytic performance and constructing a flower-like morphology composed of nanosheets.