scholarly journals Post Synthetic Defect Engineering of UiO-66 Metal-Organic Framework with Iridium(III)-HEDTA Complex and Application in Catalysis for Water Oxydation

2019 ◽  
Author(s):  
Ferdinando Costantino ◽  
Alceo Macchioni ◽  
Giordano Gatto ◽  
Roberto Bondi ◽  
Fabio Marmottini
Keyword(s):  
Water Oxidation ◽  
Metal Organic Framework ◽  
Partial Substitution ◽  
Iridium Complexes ◽  
Defect Engineering ◽  
Cerium Ammonium Nitrate ◽  
Highly Active ◽  
Metal Organic ◽  
Heterogenous Catalyst ◽  
Sacrificial Agent

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein we have used a defective zirconium MOF with UiO-66 structure as support of a highly active Ir complex based on EDTA with formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of tereftalic acid with smaller formiate groups. Anchoring of the complex occurs through a post-synthetic exchange of formiate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]-complex. The modified material was tested as heterogenous catalyst for the WO reaction by using Cerium Ammonium Nitrate as sacrificial agent. Although TOF and TON values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

scholarly journals Post Synthetic Defect Engineering of UiO-66 Metal–Organic Framework with An Iridium(III)-HEDTA Complex and Application in Water Oxidation Catalysis

Inorganics ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 123 ◽  
Author(s):  
Giordano Gatto ◽  
Alceo Macchioni ◽  
Roberto Bondi ◽  
Fabio Marmottini ◽  
Ferdinando Costantino
Keyword(s):  
Water Oxidation ◽  
Metal Organic Framework ◽  
Oxidation Catalysis ◽  
Partial Substitution ◽  
Iridium Complexes ◽  
Cerium Ammonium Nitrate ◽  
Highly Active ◽  
Water Oxidation Catalysis ◽  
Metal Organic ◽  
Organic Framework

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein, we have used a defective zirconium metal–organic framework (MOF) with UiO-66 structure as support of a highly active Ir complex based on EDTA with the formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of terephthalic acid with smaller formate groups. Anchoring of the complex occurs through a post-synthetic exchange of formate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]− complex. The modified material was tested as a heterogeneous catalyst for the WO reaction by using cerium ammonium nitrate (CAN) as the sacrificial agent. Although turnover frequency (TOF) and turnover number (TON) values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

A novel two-dimensional nickel phthalocyanine-based metal–organic framework for highly efficient water oxidation catalysis

2018 ◽  
Vol 6 (3) ◽  
pp. 1188-1195 ◽  
Author(s):  
Hongxing Jia ◽  
Yuchuan Yao ◽  
Jiangtao Zhao ◽  
Yuyue Gao ◽  
Zhenlin Luo ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Metal Organic Framework ◽  
Oxidation Catalysis ◽  
Conductive Materials ◽  
Nickel Phthalocyanine ◽  
Energy Applications ◽  
Highly Active ◽  
Water Oxidation Catalysis ◽  
Metal Organic ◽  
First Time

For the first time, we report herein bottom-up fabrication of a conductive nickel phthalocyanine-based 2D MOF and use it as a highly active electrocatalyst for OER (overpotential < 250 mV) without further pyrolysis or adding conductive materials, which can facilitate the development of 2D MOFs for energy applications.

A Ni-loaded, metal–organic framework–graphene composite as a precursor for in situ electrochemical deposition of a highly active and durable water oxidation nanocatalyst

2019 ◽  
Vol 55 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Mohamed H. Hassan ◽  
Ahmed B. Soliman ◽  
Worood A. Elmehelmey ◽  
Arwa A. Abugable ◽  
Stavros G. Karakalos ◽  
...  
Keyword(s):  
Electrochemical Deposition ◽  
Water Oxidation ◽  
Metal Organic Framework ◽  
Oxidation Catalyst ◽  
Surface Restructuring ◽  
Graphene Composite ◽  
Highly Active ◽  
Metal Organic ◽  
Restructuring Process

UiO-66-NH2 was constructed on G sheets, metallated with Ni(ii) ions, and used as a precursor to deposit a highly active water oxidation catalyst in an electrochemical surface restructuring process.

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>

scholarly journals Stepwise collapse of a giant pore metal–organic framework

2021 ◽  
Vol 50 (14) ◽  
pp. 5011-5022 ◽  
Author(s):  
Adam F. Sapnik ◽  
Duncan N. Johnstone ◽  
Sean M. Collins ◽  
Giorgio Divitini ◽  
Alice M. Bumstead ◽  
...  
Keyword(s):  
Distribution Function ◽  
Hierarchical Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Metal Organic Framework ◽  
Defect Engineering ◽  
Structural Collapse ◽  
The Hierarchical Structure ◽  
Metal Organic ◽  
Organic Framework

Defect engineering is used to augment the porosity of MIL-100. Incorporation of defects leads to structural collapse and ultimately causes amorphisation. Pair distribution function analysis reveals a stepwise collapse of the hierarchical structure.

A new superacid hafnium-based metal–organic framework as a highly active heterogeneous catalyst for the synthesis of benzoxazoles under solvent-free conditions

2017 ◽  
Vol 7 (19) ◽  
pp. 4346-4350 ◽  
Author(s):  
Linh H. T. Nguyen ◽  
The T. Nguyen ◽  
Ha L. Nguyen ◽  
Tan L. H. Doan ◽  
Phuong Hoang Tran
Keyword(s):  
Heterogeneous Catalyst ◽  
Metal Organic Framework ◽  
Solvent Free ◽  
Highly Active ◽  
Solvent Free Conditions ◽  
Metal Organic ◽  
Efficient Heterogeneous Catalyst ◽  
Organic Framework

A new superacid Hf-based MOF, termed VNU-11-P-SO4, was used as an efficient heterogeneous catalyst for solvent-free 2-arylbenzoxazole synthesis.

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.

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