Vibrational spectroscopy investigation of defects in Zr- and Hf-UiO-66

Yost, Brandon; Gibbons, Bradley; Wilson, Addison; Morris, Amanda J.; McNeil, L. E.

doi:10.1039/d2ra03131k

Cited by 9 publications

(12 citation statements)

References 28 publications

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“…The decoration of AA will lead to the inability of the COOH of NH 2 –BDC to coordinate with the Zr‐oxo cluster, thus dispersing the charge on the CN bond. [ 39 ] The characteristic peaks at 1480 and 485 cm −1 are attributed to C–S and Zr···N, respectively, which proved the successful coordination of DL‐cysteine. Also, Raman results are available at 485 cm −1 .…”

Section: Resultsmentioning

confidence: 91%

Decoration of Defective Sites in Metal–Organic Frameworks to Construct Tight Heterojunction Photocatalyst for Hydrogen Production

Qian,

Zhang,

et al. 2023

Solar RRL

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Zr–metal–organic frameworks (MOFs) have received much interest for their ultrahigh stability and are considered an up‐and‐coming class of catalysts for photocatalytic water splitting. However, their activity still needs to be improved. In this work, a series of defective UiO‐66‐NH2‐x@CdS nanoparticles (NPs) (x = 0, 50, 100, 150, 200, denotes the molar equivalent of the defect modulator) heterostructure photocatalysts is constructed for water splitting using defect engineering followed by a postmodification strategy. Defective structures are introduced to improve the photocatalytic activity of heterojunctions in the following ways: 1) modulating the energy band structure of UiO‐66‐NH2‐x, 2) providing chelate binding sites for modifying the bridging molecules and thus building strong interactions between UiO‐66‐NH2‐x and CdS NPs, and 3) serving as trapping sites to separate the photogenerated electron–hole pairs. Hence, this constructed series of UiO‐66‐NH2‐xCdS NPs exhibit ultrahigh photocatalytic water splitting for H2 production, especially UiO‐66‐NH2‐150@CdS NPs with moderately defective levels showing catalytic activity up to 2303 μmol g−1 h−1, which is 2.36 times higher than pure CdS NPs. Furthermore, the heterojunction catalysts with different defect levels exhibit a volcano‐type trend, demonstrating the feasibility of defect engineering. This work provides novel insights for developing advanced defect‐based MOF‐constructed composite photocatalysts.

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Section: Resultsmentioning

confidence: 91%

Decoration of Defective Sites in Metal–Organic Frameworks to Construct Tight Heterojunction Photocatalyst for Hydrogen Production

Qian,

Zhang,

et al. 2023

Solar RRL

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“…The low-frequency modes, in particular, will be more prone to anharmonic behavior. As the presence of defects can primarily be observed through fingerprints in the low-frequency spectrum, , the simulation of the corresponding phonon modes benefits from the dynamic approach. The experimental Raman spectrum of our UiO-66 sample does indeed feature a Raman band at 20 cm –1 (mode A in Figure ), which can, with the help of our simulations, be assigned to the presence of a cluster defect.…”

Section: Vibrational Properties Of Nanostructured Materialsmentioning

confidence: 99%

“…Second, the case of the rigid MOF UiO-66 will be treated . Although UiO-66 is a very stable MOF, it often contains defects that have an impact on its vibrational properties . Next, the MHP CsPbBr 3 will be investigated, which exhibits strong anharmonic character. , Finally, the influence of guest species within a porous framework on the vibrational fingerprints will also be studied.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, for complex nanostructured materials, their interpretation might not always be trivial due to overlapping bands. Furthermore, the presence of defects may influence the character and frequency of the phonon modes . Also, the identification of multiple guest species within porous framework materials can become cumbersome when their characteristic vibrational fingerprints overlap .…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the presence of defects may influence the character and frequency of the phonon modes. 43 Also, the identification of multiple guest species within porous framework materials can become cumbersome when their characteristic vibrational fingerprints overlap. 44 Theoretical calculations are quintessential to assist in the assignment of phonon modes.…”

Section: Introductionmentioning

confidence: 99%

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A Critical Assessment on Calculating Vibrational Spectra in Nanostructured Materials

Hoffman,

Temmerman,

Campbell

et al. 2023

J. Chem. Theory Comput.

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Vibrational spectroscopy is an omnipresent spectroscopic technique to characterize functional nanostructured materials such as zeolites, metal−organic frameworks (MOFs), and metal−halide perovskites (MHPs). The resulting experimental spectra are usually complex, with both low-frequency framework modes and high-frequency functional group vibrations. Therefore, theoretically calculated spectra are often an essential element to elucidate the vibrational fingerprint. In principle, there are two possible approaches to calculate vibrational spectra: (i) a static approach that approximates the potential energy surface (PES) as a set of independent harmonic oscillators and (ii) a dynamic approach that explicitly samples the PES around equilibrium by integrating Newton's equations of motions. The dynamic approach considers anharmonic and temperature effects and provides a more genuine representation of materials at true operating conditions; however, such simulations come at a substantially increased computational cost. This is certainly true when forces and energy evaluations are performed at the quantum mechanical level. Molecular dynamics (MD) techniques have become more established within the field of computational chemistry. Yet, for the prediction of infrared (IR) and Raman spectra of nanostructured materials, their usage has been less explored and remain restricted to some isolated successes. Therefore, it is currently not a priori clear which methodology should be used to accurately predict vibrational spectra for a given system. A comprehensive comparative study between various theoretical methods and experimental spectra for a broad set of nanostructured materials is so far lacking. To fill this gap, we herein present a concise overview on which methodology is suited to accurately predict vibrational spectra for a broad range of nanostructured materials and formulate a series of theoretical guidelines to this purpose. To this end, four different case studies are considered, each treating a particular material aspect, namely breathing in flexible MOFs, characterization of defects in the rigid MOF UiO-66, anharmonic vibrations in the metal−halide perovskite CsPbBr 3 , and guest adsorption on the pores of the zeolite H-SSZ-13. For all four materials, in their guest-and defect-free state and at sufficiently low temperatures, both the static and dynamic approach yield qualitatively similar spectra in agreement with experimental results. When the temperature is increased, the harmonic approximation starts to fail for CsPbBr 3 due to the presence of anharmonic phonon modes. Also, the spectroscopic fingerprints of defects and guest species are insufficiently well predicted by a simple harmonic model. Both phenomena flatten the potential energy surface (PES), which facilitates the transitions between metastable states, necessitating dynamic sampling. On the basis of the four case studies treated in this Review, we can propose the following theoretical guidelines to simulate accurate vibrational spectra of functional soli...

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Efficient internalization of nano architectured 177Lu-hyaluronic acid@ zirconium-based metal-organic framework for the treatment of neuroblastoma: Unravelling toxicity, stability, radiolabelling and bio-distribution

Kulkarni,

Pandey,

Soman

et al. 2024

International Journal of Biological Macromolecules

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Vibrational spectroscopy investigation of defects in Zr- and Hf-UiO-66

Abstract: Missing cluster defects in Hf-UiO-66 cause a redshift of a distinct peak in the Raman spectrum.

Cited by 9 publications

References 28 publications

Decoration of Defective Sites in Metal–Organic Frameworks to Construct Tight Heterojunction Photocatalyst for Hydrogen Production

Decoration of Defective Sites in Metal–Organic Frameworks to Construct Tight Heterojunction Photocatalyst for Hydrogen Production

A Critical Assessment on Calculating Vibrational Spectra in Nanostructured Materials

Efficient internalization of nano architectured 177Lu-hyaluronic acid@ zirconium-based metal-organic framework for the treatment of neuroblastoma: Unravelling toxicity, stability, radiolabelling and bio-distribution

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