scholarly journals Single-site photocatalysts with a porous structure

2012 ◽  
Vol 468 (2143) ◽  
pp. 2099-2112 ◽  
Author(s):  
Xiao Wei ◽  
Kai-Xue Wang ◽  
Xing-Xing Guo ◽  
Jie-Sheng Chen
Keyword(s):  
Porous Structure ◽  
Reaction Mechanisms ◽  
Metal Organic Frameworks ◽  
Charge Carriers ◽  
Single Site ◽  
Promising Strategy ◽  
Metal Organic ◽  
Better Than ◽  
Active Centres ◽  
Catalytic Performances

A photocatalytic reaction involves charge separation and transfer under photo-irradiation, and the photogenerated charge carriers (holes and electrons) are responsible for the photocatalytic activity of the catalyst. The active centres in a single-site photocatalyst are the isolated and spatially separated sites that may interact with reactants after photo-irradiation. Generally, single-site photocatalysts perform better than other types of photocatalysts owing to the presence of the efficient active centres. A porous structure can provide more single sites and special passages for charge transport. Thus, the introduction of a porous structure into a photocatalyst may result in markedly enhanced photocatalytic reactivity, providing a promising strategy for the design and fabrication of novel photocatalysts with high performances. In this review, we summarize the developments in single-site photocatalysts, particularly those with a porous structure, such as metal-incorporated zeolites, metal–organic frameworks and porous semiconductor photocatalysts. The synthesis, structures and catalytic performances of these single-site photocatalysts have been described, and characterization and reaction mechanisms for single-site photocatalysts have also been detailed. Finally, we point out the significance of study on single-site photocatalysts with a porous structure.

On the Electronic and Optical Properties of Metal-Organic Frameworks: Case Study of MIL-125 and MIL-125-NH2

2020 ◽  
Author(s):  
Gloria Capano ◽  
Francesco Ambrosio ◽  
Stavroula Kampouri ◽  
Kyriakos Stylianou ◽  
Alfredo Pasquarello ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Electronic Structure Calculations ◽  
Charge Carriers ◽  
Order Of Magnitude ◽  
Novel Material ◽  
Active Nanoparticles ◽  
Metal Organic ◽  
Structure Calculations ◽  
Catalytic Performances

<div>The photoactive MIL-125 and MIL-125-NH$_{2}$ Metal-Organic Frameworks (MOFs), despite a very similar crystalline structure, exhibit different optically behaviour. Luminescence in MIL-125 decays in about 1 ns while for its amino counterpart the lifetime of the charge-carriers is at least one order of magnitude larger. The origin of this difference is the key element for understanding the photocatalytic behaviour of MIL-125-NH<sub>2</sub> when associated with active nanoparticles, behaviour that is completely absent in MIL-125. By performing advanced</div><div>ab-initio electronic structure calculations, we find that charge-carriers interact differently in the two MOFs with subsequent effects on the luminescence lifetimes and their catalytic performances. To confirm the predictions of our model we synthesized a novel material in the MIL-125 family, MIL-125-NH<sub>2</sub>-[10%](OH)<sub>2</sub>, and confirm that our theory correctly predicts a faster decay compared to MIL-125-NH<sub>2</sub>.</div>

On the Electronic and Optical Properties of Metal-Organic Frameworks: Case Study of MIL-125 and MIL-125-NH2

2020 ◽  
Author(s):  
Gloria Capano ◽  
Francesco Ambrosio ◽  
Stavroula Kampouri ◽  
Kyriakos Stylianou ◽  
Alfredo Pasquarello ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Electronic Structure Calculations ◽  
Charge Carriers ◽  
Order Of Magnitude ◽  
Novel Material ◽  
Active Nanoparticles ◽  
Metal Organic ◽  
Structure Calculations ◽  
Catalytic Performances

<div>The photoactive MIL-125 and MIL-125-NH$_{2}$ Metal-Organic Frameworks (MOFs), despite a very similar crystalline structure, exhibit different optically behaviour. Luminescence in MIL-125 decays in about 1 ns while for its amino counterpart the lifetime of the charge-carriers is at least one order of magnitude larger. The origin of this difference is the key element for understanding the photocatalytic behaviour of MIL-125-NH<sub>2</sub> when associated with active nanoparticles, behaviour that is completely absent in MIL-125. By performing advanced</div><div>ab-initio electronic structure calculations, we find that charge-carriers interact differently in the two MOFs with subsequent effects on the luminescence lifetimes and their catalytic performances. To confirm the predictions of our model we synthesized a novel material in the MIL-125 family, MIL-125-NH<sub>2</sub>-[10%](OH)<sub>2</sub>, and confirm that our theory correctly predicts a faster decay compared to MIL-125-NH<sub>2</sub>.</div>

Green Synthesis and Enhanced CO2 Capture Performance of Perfluorinated Cerium-Based Metal-Organic Frameworks with UiO-66 and MIL-140 Topology

2018 ◽  
Author(s):  
Roberto D’Amato ◽  
Anna Donnadio ◽  
Mariolino Carta ◽  
Claudio Sangregorio ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Organic Frameworks ◽  
Isosteric Heat ◽  
Experimental Conditions ◽  
Cerium Ammonium Nitrate ◽  
Ideal Adsorbed Solution Theory ◽  
Metal Organic ◽  
Adsorbed Solution ◽  
Better Than ◽  
The Ideal

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO<sub>2</sub> sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO<sub>2</sub> over N<sub>2</sub>: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO<sub>2 </sub>adsorption is in the range of 38-40 kJ mol<sup>-1</sup>, indicating a strong physisorptive character.

Lawsone Derived Zn (II) and Fe (III) Metal Organic Frameworks with pH Dependent Emission for Controlled Drug Delivery

2021 ◽  
Author(s):  
Sirajunnisa P ◽  
Liz Hannah George ◽  
Narayanapillai Manoj ◽  
Prathapan S ◽  
G.S. Sailaja
Keyword(s):  
Drug Delivery ◽  
Porous Structure ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
High Surface Area ◽  
Controlled Drug Delivery ◽  
Sensing Applications ◽  
Porous Carriers ◽  
Metal Organic ◽  
Ph Dependent

Fluorescent biocompatible porous carriers have been investigated as suitable probes for drug delivery and sensing applications owing to their intrinsic fluorescence and high surface area originating from their porous structure...

A series of microporous and robust Ln-MOFs showing luminescent properties and catalytic performances towards Knoevenagel reactions

2021 ◽  
Author(s):  
Qing-Xia Yao ◽  
Miaomiao Tian ◽  
Jun Zheng ◽  
Jintang Xue ◽  
Xuze Pan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Metal Organic Frameworks ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic ◽  
Catalytic Performances

A series of microporous Ln(III)-based metal-organic frameworks (1-Ln) have been hydrothermally synthesized by using 4,4',4''-nitrilotribenzoic acid (H3NTB). Single crystal X-ray diffraction analyses show 1-Ln are isostructural and have 3D porous...

scholarly journals Including dispersion in density functional theory for adsorption on flat oxide surfaces, in metal–organic frameworks and in acidic zeolites

2020 ◽  
Vol 22 (14) ◽  
pp. 7577-7585 ◽  
Author(s):  
Florian R. Rehak ◽  
GiovanniMaria Piccini ◽  
Maristella Alessio ◽  
Joachim Sauer
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Van Der Waals ◽  
Metal Organic Frameworks ◽  
Many Body ◽  
Functional Theory ◽  
Metal Organic ◽  
The Many ◽  
Acidic Zeolites ◽  
Better Than

Contrary to common believe, for eight adsorption cases, neither D3 or TS are an improvement compared to D2 nor van der Waals functionals or dDsC. Only the many body approaches are slightly better than D2(Ne) which uses Ne parameters for Mg2+ ions.

scholarly journals Homocoupling Reactions of Azoles and Their Applications in Coordination Chemistry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5950
Author(s):  
Steffen B. Mogensen ◽  
Mercedes K. Taylor ◽  
Ji-Woong Lee
Keyword(s):  
Coordination Chemistry ◽  
Reaction Mechanisms ◽  
Metal Organic Frameworks ◽  
Ring System ◽  
Membered Ring ◽  
Materials Chemistry ◽  
Structural Class ◽  
Basic Nitrogen ◽  
Metal Organic ◽  
Metal Catalyzed

Pyrazole, a member of the structural class of azoles, exhibits molecular properties of interest in pharmaceuticals and materials chemistry, owing to the two adjacent nitrogen atoms in the five-membered ring system. The weakly basic nitrogen atoms of deprotonated pyrazoles have been applied in coordination chemistry, particularly to access coordination polymers and metal-organic frameworks, and homocoupling reactions can in principle provide facile access to bipyrazole ligands. In this context, we summarize recent advances in homocoupling reactions of pyrazoles and other types of azoles (imidazoles, triazoles and tetrazoles) to highlight the utility of homocoupling reactions in synthesizing symmetric bi-heteroaryl systems compared with traditional synthesis. Metal-free reactions and transition-metal catalyzed homocoupling reactions are discussed with reaction mechanisms in detail.

scholarly journals Front Cover: Design of Single-Site Photocatalysts by Using Metal-Organic Frameworks as a Matrix (Chem. Asian J. 14/2018)

2018 ◽  
Vol 13 (14) ◽  
pp. 1756-1756
Author(s):  
Meicheng Wen ◽  
Kohsuke Mori ◽  
Yasutaka Kuwahara ◽  
Taicheng An ◽  
Hiromi Yamashita
Keyword(s):  
Metal Organic Frameworks ◽  
Single Site ◽  
Front Cover ◽  
Metal Organic ◽  
Cover Design
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