Regioselectivity in Pyrene-Templated Polymerization Using MOFs as 1D Porous Scaffolds.

Physicochemical properties of polymers strongly depend on the arrangement and distribution of attached monomers. Templated polymerization using porous crystalline materials appears as a promising route to gain control on the process. Thus, we demonstrate here the potential of metal-organic frameworks as scaffolds with a versatile and very regular porosity, well adapted for the regioselective oxidative polymerization of pyrene.

Heteroepitaxial MOF-on-MOF Photocatalyst for Solar-Driven Water Splitting.

Assembly of different metal-organic frameworks (MOFs) into hybrid MOF-on-MOF heterostructures has been established as a promising approach to develop synergistic performances for a variety of applications. Here, we explore the performance of a MOF-on-MOF heterostructure by epitaxial growth of MIL-88B(Fe) onto UiO-66(Zr)-NH nanoparticles. The face-selective design and appropriate energy band structure alignment of the selected MOF constituents have permitted its application as an active heterogeneous photocatalyst for solar-driven water splitting.

Design of Multivariate Biological Metal-Organic Frameworks: Toward Mimicking Active Sites of Enzymes.

Mimicking enzymatic processes carried out by natural enzymes, which are highly efficient biocatalysts with key roles in living organisms, attracts much interest but constitutes a synthetic challenge. Biological metal-organic frameworks (bioMOFs) are potential candidates to be enzyme catalysis mimics, as they offer the possibility to combine biometals and biomolecules into open-framework porous structures capable of simulating the catalytic pockets of enzymes. In this work, we first study the catalase activity of a previously reported bioMOF, derived from the amino acid -serine, with formula {CaCu[(,)-serimox](OH)(HO)} · 39HO () (serimox = bis[(S)-serine]oxalyl diamide), which is indeed capable to mimic catalase enzymes, in charge of preventing cell oxidative damage by decomposing, efficiently, hydrogen peroxide to water and oxygen (2HO → 2 HO + O).

Hydrogel composites based on chitosan and CuAuTiO photocatalysts for hydrogen production under simulated sunlight irradiation.

This study explored the photocatalytic hydrogen evolution reaction (HER) using novel biohydrogel composites comprising chitosan, and a photocatalyst consisting in TiO P25 decorated with Au and/or Cu mono- and bimetallic nanoparticles (NPs) to boost its optical and catalytic properties. Low loads of Cu and Au (1 mol%) were incorporated onto TiO via a green photodeposition methodology. Characterization techniques confirmed the incorporation of decoration metals as well as improvements in the light absorption properties in the visible light interval (λ > 390 nm) and electron transfer capability of the semiconductors.

Solar Gas-Phase CO Hydrogenation by Multifunctional UiO-66 Photocatalysts.

Solar-assisted CO conversion into fuels and chemical products involves a range of technologies aimed at driving industrial decarbonization methods. In this work, we report on the development of a series of multifunctional metal-organic frameworks (MOFs) based on nitro- or amino-functionalized UiO-66(M) (M: Zr or Zr/Ti) supported RuO NPs as photocatalysts, having different energy band level diagrams, for CO hydrogenation under simulated concentrated sunlight irradiation. RuO(1 wt %; 2.

Valorization of Field-Spent Granular Activated Carbon as Heterogeneous Ozonation Catalyst for Water Treatment.

Developing sustainable cost-effective strategies for valorization of field-spent granular activated carbon (s-GAC) from industrial water treatment has gained much interest. Here, we report a cost-effective strategy for the regeneration of s-GAC as an adsorbent in a large-scale drinking water treatment plant and used as an efficient and durable ozonation catalyst in water. To achieve this, a series of samples is prepared by subjecting s-GAC to thermally controlled combustion treatments with and without pyrolysis.

Selective Gas-Phase Hydrogenation of CO to Methanol Catalysed by Metal-Organic Frameworks.

Large scale production of green CH OH obtained from CO and green H is a highly wanted process due to the role of CH OH as H /energy carrier and for producing chemicals. Starting with a short summary of the advantages of metal-organic frameworks (MOFs) as catalysts in liquid-phase reactions, the present article highlights the opportunities that MOFs may offer also for some gas-phase reactions, particularly for the selective CO hydrogenation to CH OH. It is commented that there is a temperature compatibility window that combines the thermal stability of some MOFs with the temperature required in the CO hydrogenation to CH OH that frequently ranges from 250 to 300 °C.

Porphyrin-Based MOF Thin Film on Transparent Conducting Oxide: Investigation of Growth, Porosity and Photoelectrochemical Properties.

Synthesizing metal-organic frameworks (MOFs) composites with a controlled morphology is an important requirement to access materials of desired patterning and composition. Since the last decade, MOF growth from sacrificial metal oxide layer is increasingly developed as it represents an efficient pathway to functionalize a large number of substrates. In this study, porphyrin-based Al-PMOF thin films were grown on conductive transparent oxide substrates from sacrificial layers of ALD-deposited alumina oxide.

Room temperature design of Ce(iv)-MOFs: from photocatalytic HER and OER to overall water splitting under simulated sunlight irradiation.

The development of MOF-based efficient and reusable catalysts for hydrogen production under simulated sunlight irradiation, especially through overall water splitting, remains challenging. This is mainly due to either the inappropriate optical features or poor chemical stability of the given MOFs. Room temperature synthesis (RTS) of tetravalent MOFs is a promising strategy to design robust MOFs and their related (nano)composites.

Metal Node Control of Brønsted Acidity in Heterobimetallic Titanium-Organic Frameworks.

Compared to indirect framework modification, synthetic control of cluster composition can be used to gain direct access to catalytic activities exclusive of specific metal combinations. We demonstrate this concept by testing the aminolysis of epoxides with a family of isostructural mesoporous frameworks featuring five combinations of homometallic and heterobimetallic metal-oxo trimers (Fe, Ti, TiFe, TiCo, and TiNi). Only TiFe nodes display activities comparable to benchmark catalysts based on grafting of strong acids, which here originate from the combination of Lewis Ti and Brønsted Fe-OH acid sites.

Metal-Organic Frameworks as Photocatalysts for Solar-Driven Overall Water Splitting.

Metal-organic frameworks (MOFs) have been frequently used as photocatalysts for the hydrogen evolution reaction (HER) using sacrificial agents with UV-vis or visible light irradiation. The aim of the present review is to summarize the use of MOFs as solar-driven photocatalysts targeting to overcome the current efficiency limitations in overall water splitting (OWS). Initially, the fundamentals of the photocatalytic OWS under solar irradiation are presented.

Photocatalytic Hydrogen Production from Glycerol Aqueous Solutions as Sustainable Feedstocks Using Zr-Based UiO-66 Materials under Simulated Sunlight Irradiation.

There is an increasing interest in developing cost-effective technologies to produce hydrogen from sustainable resources. Herein we show a comprehensive study on the use of metal-organic frameworks (MOFs) as heterogeneous photocatalysts for H generation from photoreforming of glycerol aqueous solutions under simulated sunlight irradiation. The list of materials employed in this study include some of the benchmark Zr-MOFs such as UiO-66(Zr)-X (X: H, NO, NH) as well as MIL-125(Ti)-NH as the reference Ti-MOF.

Graphitic Carbon Nitride as Visible-Light Photocatalyst Boosting Ozonation in Wastewater Treatment.

Light can boost ozone efficiency in advanced oxidation processes (AOPs), either by direct ozone photolysis with UV light or by using a photocatalyst that can be excited with UV-Vis or solar light. The present review summarizes literature data on the combination of ozone and the g-CN photocatalyst for the degradation of probe molecules in water, including oxalic, p-hydroxybenzoic and oxamic acids as well as ciprofloxacin and parabens. g-CN is a metal-free visible-light photocatalyst based on abundant elements that establishes a synergistic effect with ozone, the efficiency of the combination of the photocatalysis and ozonation being higher than the sum of the two treatments independently.

A Novel Porous Ti-Squarate as Efficient Photocatalyst in the Overall Water Splitting Reaction under Simulated Sunlight Irradiation.

A new porous titanium(IV) squarate metal-organic framework (MOF), denoted as IEF-11, having a never reported titanium secondary building unit, is successfully synthesized and fully characterized. IEF-11 not only exhibits a permanent porosity but also an outstanding chemical stability. Further, as a consequence of combining the photoactive Ti(IV) and the electroactive squarate, IEF-11 presents relevant optoelectronic properties, applied here to the photocatalytic overall water splitting reaction.

Photoactive Zr and Ti Metal-Organic-Frameworks for Solid-State Solar Cells.

Solid-state photovoltaic cells based on robust metal-organic frameworks (MOFs), MIL-125(Ti), MIL-125(Ti)-NH , UiO-67, Ru(bpy) -UiO-67, (bpy 2,2'-bipyridine) as active components and spiro-MeOTAD (MeOTAD 2,2',7,7'-tetrakis[N,N-di(p-methoxyphenyl)amino]-9,9'-spirobifluorene) as hole transporting layer have been prepared., The photovoltaic response of this material increases in the presence of bathochromic -NH groups on the linker or Ru (II) polypyridyl complexes light harvester. These results show that the strategies typically employed in photocatalysis to enhance the photocatalytic activity of MOFs can also be applied in the field of photovoltaic devices.

Selective Implantation of Diamines for Cooperative Catalysis in Isoreticular Heterometallic Titanium-Organic Frameworks.

We introduce the first example of isoreticular titanium-organic frameworks, MUV-10 and MUV-12, to show how the different affinity of hard Ti(IV) and soft Ca(II) metal sites can be used to direct selective grafting of amines. This enables the combination of Lewis acid titanium centers and available -NH sites in two sizeable pores for cooperative cycloaddition of CO to epoxides at room temperature and atmospheric pressure. The selective grafting of molecules to heterometallic clusters adds up to the pool of methodologies available for controlling the positioning and distribution of chemical functions in precise positions of the framework required for definitive control of pore chemistry.

Plasma-Induced Defects Enhance the Visible-Light Photocatalytic Activity of MIL-125(Ti)-NH for Overall Water Splitting.

Defect engineering in metal-organic frameworks is commonly performed by using thermal or chemical treatments. Herein we report that oxygen plasma treatment generates structural defects on MIL-125(Ti)-NH , leading to an increase in its photocatalytic activity. Characterization data indicate that plasma-treated materials retain most of their initial crystallinity, while exhibiting somewhat lower surface area and pore volume.

Bifunctional metal-organic frameworks for the hydrogenation of nitrophenol using methanol as the hydrogen source.

This work reports the reduction of 4-nitrophenol to 4-aminophenol using UiO-66(Zr) as a bifunctional photocatalyst and hydrogenation catalyst using methanol as the hydrogen source. In particular, a series of UiO-66(Zr)-X (X: NH, NO and H) and MIL-125(Ti)-NH catalysts have been screened as bifunctional catalysts for this process. UiO-66(Zr)-NH was found to be the most active material to promote light-assisted nitro hydrogenation under both UV-Vis and simulated sunlight irradiation.

Gold-Nanoparticle-Decorated Metal-Organic Frameworks for Anticancer Therapy.

Confinement of Au nanoparticles (NPs) within the porous materials with few nanometers (2-3 nm) has been a well established research area in the past decades in heterogeneous catalysis mainly due to the unique behaviour of Au NPs than its bulk counterpart. In this aspect, Au NPs encapsulated within the pore volumes of metal-organic frameworks (MOFs) have been intensively explored as heterogeneous solid catalysts for wide range of reactions. In recent years, Au NPs confined within the porous MOFs along with the photosensitizer or drug have been effectively used for the treatment of tumor cells through the generation of reactive oxygen species via cascade reactions.

Impact of chlorination and pre-ozonation on disinfection by-products formation from aqueous suspensions of cyanobacteria: Microcystis aeruginosa, Anabaena aequalis and Oscillatoria tenuis.

The influence of the pre-ozonization on the formation of disinfection by-products (DBPs) upon chlorination for fresh waters containing three common cyanobacteria, namely Microcystis aeruginosa, Anabaena aequalis and Oscillatoria tenuis at 10,000 cells/mL is reported. Specifically, the formation carbonaceous-DBPs (C-DBPs) (trihalomethanes (THMs), haloacetic acids (HAAs) and haloketones (HKs)) and nitrogenous-DBPs (N-DBP) (haloacetonitriles (HAN) and trichloronitromethane (TCNM)) has been determined as a function of the pH (6.5 or 8.

A Pyridyltriazol Functionalized Zirconium Metal-Organic Framework for Selective and Highly Efficient Adsorption of Palladium.

This work reports the synthesis of pyridyltriazol-functionalized UiO-66 (UiO stands for University of Oslo), namely, UiO-66-Pyta, from UiO-66-NH through three postsynthetic modification (PSM) steps. The good performance of the material derives from the observation that partial formylation (∼21% of -NHCHO groups) of HBDC-NH by DMF, as persistent impurity, takes place during the synthesis of the UiO-66-NH. Thus, to enhance material performance, first, the as-synthesized UiO-66-NH was deformylated to give pure UiO-66-NH.

Alteration of the Mitochondrial Effects of Ceria Nanoparticles by Gold: An Approach for the Mitochondrial Modulation of Cells Based on Nanomedicine.

Ceria nanoparticles are cell compatible antioxidants whose activity can be enhanced by gold deposition and by surface functionalization with positive triphenylphosphonium units to selectively target the mitochondria. The antioxidant properties of these nanoparticles can serve as the basis of a new strategy for the treatment of several disorders exhibiting oxidative stress, such as cancer, diabetes or Alzheimer's disease. However, all of these pathologies require a specific antioxidant according with their mechanism to remove oxidant species excess in cells and diminish their effect on mitochondrial function.

A Semiconducting BiO(CO) Coordination Polymer Showing a Photoelectric Response.

Inorganic semiconductors are extensively considered to be among the most promising materials to convert solar light into electricity or chemical energy owing to their efficiency in the separation of photoinduced electron/hole. Bismuth oxides, and, in particular, those built up of [BiO] layers, show an efficient charge separation and, thus, high photocatalytic activities. To explore a possible synergetic effect of bismuth metallic nodes combined with the electron-rich linker squarate, BiO(CO) or IEF-3 (an IMDEA Energy framework) was hydrothermally prepared and adequately characterized.

Metal organic frameworks as solid catalysts for liquid-phase continuous flow reactions.

Metal organic frameworks (MOFs) are widely used as solid catalysts in the liquid phase under batch mode conditions. Moving towards the development of industrial processes, data of the performance of MOFs under continuous flow operation would be desirable. This feature article describes the state of the art regarding the use of MOFs as catalysts of continuous flow processes, paying special attention to the issue of catalyst stability.