scholarly journals Band Gap Modulation in Zirconium-Based Metal-Organic Frameworks by Defect Engineering

2019 ◽  
Author(s):  
Marco Taddei ◽  
Giulia M. Schukraft ◽  
Michael E. A. Warwick ◽  
Davide Tiana ◽  
Matthew McPherson ◽  
...  
Keyword(s):  
Band Gap ◽  
Gas Phase ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Benzoic Acids ◽  
Defect Engineering ◽  
Metal Organic ◽  
Band Gap Modulation ◽  
Valence Band Energy ◽  
Defective Sites

We report a defect-engineering approach to modulate the band gap of zirconium-based metal-organic framework UiO-66, enabled by grafting of a range of amino-functionalised benzoic acids at defective sites. Defect engineered MOFs were obtained by both post-synthetic exchange and modulated synthesis, featuring band gap in the 4.1-3.3 eV range. Ab-initio calculations suggest that shrinking of the band gap is mainly due to an upward shift of the valence band energy, as a result of the presence of light-absorbing monocarboxylates. The photocatalytic properties of defect-engineered MOFs towards CO<sub>2</sub> reduction to CO in the gas phase and degradation of Rhodamine B in water were tested, observing improved activity in both cases, in comparison to a defective UiO-66 bearing formic acid as the defect-compensating species.

scholarly journals Band Gap Modulation in Zirconium-Based Metal-Organic Frameworks by Defect Engineering

2019 ◽  
Author(s):  
Marco Taddei ◽  
Giulia M. Schukraft ◽  
Michael E. A. Warwick ◽  
Davide Tiana ◽  
Matthew McPherson ◽  
...  
Keyword(s):  
Band Gap ◽  
Gas Phase ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Benzoic Acids ◽  
Defect Engineering ◽  
Metal Organic ◽  
Band Gap Modulation ◽  
Valence Band Energy ◽  
Defective Sites

We report a defect-engineering approach to modulate the band gap of zirconium-based metal-organic framework UiO-66, enabled by grafting of a range of amino-functionalised benzoic acids at defective sites. Defect engineered MOFs were obtained by both post-synthetic exchange and modulated synthesis, featuring band gap in the 4.1-3.3 eV range. Ab-initio calculations suggest that shrinking of the band gap is mainly due to an upward shift of the valence band energy, as a result of the presence of light-absorbing monocarboxylates. The photocatalytic properties of defect-engineered MOFs towards CO<sub>2</sub> reduction to CO in the gas phase and degradation of Rhodamine B in water were tested, observing improved activity in both cases, in comparison to a defective UiO-66 bearing formic acid as the defect-compensating species.

scholarly journals Band Gap Modulation in Zirconium-Based Metal-Organic Frameworks by Defect Engineering

2019 ◽  
Author(s):  
Marco Taddei ◽  
Giulia M. Schukraft ◽  
Michael E. A. Warwick ◽  
Davide Tiana ◽  
Matthew McPherson ◽  
...  
Keyword(s):  
Band Gap ◽  
Gas Phase ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Benzoic Acids ◽  
Defect Engineering ◽  
Metal Organic ◽  
Band Gap Modulation ◽  
Valence Band Energy ◽  
Defective Sites

We report a defect-engineering approach to modulate the band gap of zirconium-based metal-organic framework UiO-66, enabled by grafting of a range of amino-functionalised benzoic acids at defective sites. Defect engineered MOFs were obtained by both post-synthetic exchange and modulated synthesis, featuring band gap in the 4.1-3.3 eV range. Ab-initio calculations suggest that shrinking of the band gap is mainly due to an upward shift of the valence band energy, as a result of the presence of light-absorbing monocarboxylates. The photocatalytic properties of defect-engineered MOFs towards CO<sub>2</sub> reduction to CO in the gas phase and degradation of Rhodamine B in water were tested, observing improved activity in both cases, in comparison to a defective UiO-66 bearing formic acid as the defect-compensating species.

scholarly journals Band gap modulation in zirconium-based metal–organic frameworks by defect engineering

2019 ◽  
Vol 7 (41) ◽  
pp. 23781-23786 ◽  
Author(s):  
Marco Taddei ◽  
Giulia M. Schukraft ◽  
Michael E. A. Warwick ◽  
Davide Tiana ◽  
Matthew J. McPherson ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Defect Engineering ◽  
Engineering Approach ◽  
Metal Organic ◽  
Engineered Materials ◽  
Band Gap Modulation ◽  
Organic Framework

A simple defect engineering approach to systematically tune the band gap of the prototypical zirconium-based metal–organic framework UiO-66 is reported. Defect engineered materials display enhanced photocatalytic activity.

Engineering Porosity Through Defects in a Giant Pore Metal–Organic Framework

2020 ◽  
Author(s):  
Adam Sapnik ◽  
Duncan Johnstone ◽  
Sean M. Collins ◽  
Giorgio Divitini ◽  
Alice Bumstead ◽  
...  
Keyword(s):  
Distribution Function ◽  
Ball Milling ◽  
Local Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Defect Engineering ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Defect engineering is a powerful tool that can be used to tailor the properties of metal–organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal–linker bonds, generating more coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially</p><p>retained, even in the amorphised material. We find that the solvent toluene stabilises the MIL-100 (Fe) framework against collapse and leads to a substantial rentention of porosity over the non-stabilised material.</p>

Band gap modulation of functionalized metal–organic frameworks

2014 ◽  
Vol 16 (43) ◽  
pp. 23646-23653 ◽  
Author(s):  
Terence Musho ◽  
Jiangtan Li ◽  
Nianqiang Wu
Keyword(s):  
Band Gap ◽  
Metal Organic Frameworks ◽  
Fuel Conversion ◽  
Metal Organic ◽  
Band Gap Modulation

Metal–organic frameworks (MOFs) have been envisioned as alternatives to planar metallic catalysts for solar-to-fuel conversion.

scholarly journals Direct Imaging of Correlated Defect Nanodomains in a Metal-Organic Framework

2020 ◽  
Author(s):  
Duncan Johnstone ◽  
Francesca Firth ◽  
Clare P. Grey ◽  
Paul A. Midgley ◽  
Matthew Cliffe ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Electron Diffraction ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Synthetic Control ◽  
Defect Engineering ◽  
Nanoscale Characterization ◽  
Metal Organic ◽  
Image Defect ◽  
Scanning Electron

<p>Defect engineering can enhance key properties of metal-organic frameworks (MOFs). Tailoring the distribution of defects, for example in correlated nanodomains, requires characterization across length scales. However, a critical nanoscale characterization gap has emerged between the bulk diffraction techniques used to detect defect nanodomains and the sub-nanometre imaging used to observe individual defects. Here, we demonstrate that the emerging technique of scanning electron diffraction (SED) can bridge this gap. We directly image defect nanodomains in the MOF UiO-66(Hf) over an area of ca. 1 000 nm and with a spatial resolution ca. 5 nm to reveal domain morphology and distribution. Based on these observations, we suggest possible crystal growth processes underpinning synthetic control of defect nanodomains. We also identify likely dislocations and small angle grain boundaries, illustrating that SED could be a key technique in developing the potential for engineering the distribution of defects, or “microstructure”, in functional MOF design.</p>

scholarly journals Phosphonate Metal-Organic Frameworks: A Novel Family of Semiconductors

2020 ◽  
Author(s):  
Konrad Siemensmeyer ◽  
Craig A. Peeples ◽  
Patrik Tholen ◽  
Bünyemin Çoşut ◽  
Gabriel Hanna ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Band Gap ◽  
Narrow Band ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
One Dimensional ◽  
Metal Organic ◽  
Copper Dimers ◽  
Electrodes For Supercapacitors

<p>Herein is reported the first semiconducting and magnetic phosphonate metal-organic framework (MOF), TUB75, which contains a one-dimensional inorganic building unit composed of a zig-zag chain of corner-sharing copper dimers. The solid-state UV-Vis spectrum of TUB75 reveals the existence of a narrow band gap of 1.4 eV, which agrees well with the 1.77 eV one obtained from DFT calculations. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors. </p>

scholarly journals Direct Imaging of Correlated Defect Nanodomains in a Metal-Organic Framework

2020 ◽  
Author(s):  
Duncan Johnstone ◽  
Francesca Firth ◽  
Clare P. Grey ◽  
Paul A. Midgley ◽  
Matthew Cliffe ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Electron Diffraction ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Synthetic Control ◽  
Defect Engineering ◽  
Nanoscale Characterization ◽  
Metal Organic ◽  
Image Defect ◽  
Scanning Electron

<p>Defect engineering can enhance key properties of metal-organic frameworks (MOFs). Tailoring the distribution of defects, for example in correlated nanodomains, requires characterization across length scales. However, a critical nanoscale characterization gap has emerged between the bulk diffraction techniques used to detect defect nanodomains and the sub-nanometre imaging used to observe individual defects. Here, we demonstrate that the emerging technique of scanning electron diffraction (SED) can bridge this gap. We directly image defect nanodomains in the MOF UiO-66(Hf) over an area of ca. 1 000 nm and with a spatial resolution ca. 5 nm to reveal domain morphology and distribution. Based on these observations, we suggest possible crystal growth processes underpinning synthetic control of defect nanodomains. We also identify likely dislocations and small angle grain boundaries, illustrating that SED could be a key technique in developing the potential for engineering the distribution of defects, or “microstructure”, in functional MOF design.</p>

scholarly journals Study of the inorganic substitution in a functionalized UiO-66 metal–organic framework

2016 ◽  
Vol 18 (18) ◽  
pp. 12748-12754 ◽  
Author(s):  
Alhassan Salman Yasin ◽  
Jiangtian Li ◽  
Nianqiang Wu ◽  
Terence Musho
Keyword(s):  
Band Gap ◽  
Metal Organic Framework ◽  
Metal Organic ◽  
Band Gap Modulation ◽  
Organic Framework

A study of the band gap modulation in response to the inorganic substitution of the UiO-66 functionalized MOF.

scholarly journals Metal-organic framework UiO-66 membranes

2019 ◽  
Vol 14 (2) ◽  
pp. 216-232 ◽  
Author(s):  
Xinlei Liu
Keyword(s):  
Gas Phase ◽  
Electrochemical Deposition ◽  
Synthesis Gas ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Ion Separation ◽  
Metal Organic ◽  
Scalable Synthesis ◽  
Gas Phase Deposition

AbstractMetal-organic frameworks (MOFs) have emerged as a class of promising membrane materials. UiO-66 is a prototypical and stable MOF material with a number of analogues. In this article, we review five approaches for fabricating UiO-66 polycrystalline membranes including in situ synthesis, secondary synthesis, biphase synthesis, gas-phase deposition and electrochemical deposition, as well as their applications in gas separation, pervaporation, nanofiltration and ion separation. On this basis, we propose possible methods for scalable synthesis of UiO-66 membranes and their potential separation applications in the future.

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