The ineffective removal of antibiotics from the aquatic environment has raised serious problems, including chronic toxicity and antibiotic resistance. Among the numerous strategies, photocatalytic degradation appears to be one of the promising methods to remove antibiotics. Semiconductors are the most widely used photocatalysts, whereas, their efficiencies still suffer from limited light absorption and poor charge separation. Given their exceptional properties, including a superior surface area and massive active sites, MOFs are excellent candidates for the formation of hierarchical nanostructures with semiconductors to address the above issues. In this study, highly-oriented one-dimensional (1D) MIL-100(Fe)/TiO 2 nanoarrays were developed as photocatalysts for the first time (MIL = Materials Institute Lavoisier). The 1D structured TiO 2 nanoarrays not only enable the direct and enhanced charge transport, but also permit easy recycling. With the in situ growth of MIL-100(Fe) on the TiO 2 nanoarrays, the composite exhibits enhanced light absorption, electron/hole separation, and accessibility of active sites. As a result, up to 90.79% photodegradation efficiency of tetracycline, a representative antibiotic, by the MIL-100(Fe)/TiO 2 composite nanoarrays was achieved, which is much higher than that of pristine TiO 2 nanoarrays (35.22%). It is also worth mentioning that the composite nanoarrays demonstrate high stability and still exhibit high efficiency twice that of the pristine TiO 2 nanoarrays even in the 5th run. This study offers a new strategy for the degradation of antibiotics by using 1D MOF-based nanocomposite nanoarrays.
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Electron shuttle in the MOF derived TiO 2 /CuO heterojunction boosts light driven hydrogen evolution
Metal organic frameworks (MOFs) have emerged as a novel template to develop porous photocatalytic materials for solar fuel conversion. In this work, we report the synthesis, charge separation dynamics, and photocatalytic performance of the TiO 2 /CuO heterostructure derived from mixed-phase MOFs based on Ti and Cu metal nodes, which demonstrates significantly enhanced catalytic activity for the hydrogen evolution reaction (HER) compared to metal oxides derived from single node MOFs. More importantly, using transient absorption spectroscopy, we identified the specific role each component in the heterostructure plays and unravelled the key intermediate species that is responsible for the exceptional photocatalytic activity of the heterostructure. We found that the HER is initiated with ultrafast electron transfer (<150 fs) from the molecular photosensitizer to the conduction band of TiO 2 , where TiO 2 acts as an electron mediator and shuttles the electron to the CuO cocatalyst, facilitating charge separation and ultimately boosting the HER efficiency. These results not only demonstrate the great potential of using mixed-phase MOFs as templates to synthesize mesoporous heterostructure photocatalysts but also provide important insight into the HER mechanism.
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- Award ID(s):
- 1706971
- NSF-PAR ID:
- 10303780
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 9
- Issue:
- 10
- ISSN:
- 2050-7488
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0TA12220C
