کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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6454940 | 1418819 | 2017 | 10 صفحه PDF | دانلود رایگان |
- Double-shelled and sandwiched TiO2@Au@CeO2 hollow spheres are prepared.
- The important of controllable location of the noble metals as cocatalysts is proved.
- The electron-hole separation of TiO2@Au@CeO2 is improved.
- The photo-degradation of aromatic pollutants is enhanced.
Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Although TiO2 is the most popular photocatalyst, the lack of visible light utilization and a low efficiency of electron-hole separation should be overcome. Therefore, Au nanoparticles (NPs) as cocatalyst were controllably loaded between the double-shell or into CeO2 shell (as photocatalyst and oxygen buffer) and then a novel visible-light-driven TiO2@CeO2 nanocomposite was prepared, using functionalized polystyrene spheres, sol-gel, hydrothermal reaction, and calcination. The presence of TiO2 shell, Au NPs and CeO2 shell were confirmed by EDX and electron energy loss mapping analysis. Under visible-light irradiation, the photo-degradation rate constant k (minâ1) was in the order of TiO2@Au@CeO2 (0.026)Â >Â TiO2@CeO2/Au (0.021)Â >Â TiO2@CeO2 (0.014)Â >Â CeO2 (0.0091)Â >Â TiO2 (0.0046)Â >Â P25 (0.0034). Compared with P25, TiO2@CeO2, and TiO2@CeO2/Au, the visible-light photocatalytic activity of TiO2@Au@CeO2 for the photo-degradation of organic pollutant and photo-reduction of Cr(VI) were the highest. This result was attributed to the combination of TiO2 and CeO2, the double-shelled and sandwiched nanostructure and the addition of Au NPs as electron trap site and surface plasmon resonance-sensitizer, which could reduce the recombination of the electron-hole and induce the visible light absorption. The major obstacle of heterogeneous photocatalysis could be resolved. The photo-degradation rate of 95% was achieved by TiO2@Au@CeO2, which exhibited an increase of 63% compared to Degussa P25 TiO2. The photo-degradation activity of TiO2@CeO2/Au was improved by Au NPs loaded on outer shell of TiO2@CeO2/Au but limited by their stability. This work confirmed the importance of controllable location of the noble metals as cocatalysts.
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Journal: Applied Catalysis B: Environmental - Volume 201, February 2017, Pages 12-21