Photoinduced water oxidation by an organic ligand incorporated into the framework of a stable metal-organic framework.
Ontology highlight
ABSTRACT:
SUBMITTER: Gong YN
PROVIDER: S-EPMC5590092 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A molecular water oxidation catalyst, [Ru(tpy)(dcbpy)(OH2)](ClO4)2 (tpy = 2,2':6',2''-terpyridine, dcbpy = 2,2'-bipyridine-5,5'-dicarboxylic acid) [1], has been incorporated into FTO-grown thin films of UiO-67 (UiO = University of Oslo), by post-synthetic ligand exchange. Cyclic voltammograms (0.1 M borate buffer at pH = 8.4) of the resulting UiO67-[RuOH2]@FTO show a reversible wave associated with the RuIII/II couple in the anodic scan, followed by a large current response that arises from electrocatalytic water oxidation beyond 1.1 V vs. Ag/AgCl. Water oxidation can be observed at an applied potential of 1.5 V over the timescale of hours with a current density of 11.5 ?A cm-2. Oxygen evolution was quantified in situ over the course of the experiment, and the Faradaic efficiency was calculated as 82%. Importantly, the molecular integrity of [1] during electrocatalytic water oxidation is maintained even on the timescale of hours under turnover conditions and applied voltage, as evidenced by the persistence of the wave associated with the RuIII/II couple in the CV. This experiment highlights the capability of metal organic frameworks like UiO-67 to stabilize the molecular structure of catalysts that are prone to form higher clusters in homogenous phase.
| S-EPMC6095457 | biostudies-literature
Project description:Extensive efforts have been devoted to developing efficient and durable catalysts for water oxidation. Herein, we report a highly stable metal-organic framework that shows high catalytic activity and durability for electrically driven (an overpotential of 430 mV at 10 mA cm-2 in neutral aqueous solution) and photodriven (a turnover frequency of 16 s-1 and 12?000 cycles) water oxidation, representing the best catalyst for water oxidation reported to date. Computational simulation and isotope tracing experiments showed that the ?4-OH group of the {Co8(?4-OH)6} unit participates in the water oxidation reaction to offer an oxygen vacancy site with near-optimal OH- adsorption energy.
| S-EPMC6977550 | biostudies-literature
Project description:Owing to the rich porosity and uniform pore size, metal-organic frameworks (MOFs) offer substantial advantages over other materials for the precise and fast membrane separation. However, achieving ultrathin water-stable MOF membranes remains a great challenge. Here, we first report the successful exfoliation of two-dimensional (2D) monolayer aluminum tetra-(4-carboxyphenyl) porphyrin framework (termed Al-MOF) nanosheets. Ultrathin water-stable Al-MOF membranes are assembled by using the exfoliated nanosheets as building blocks. While achieving a water flux of up to 2.2 mol m?2 hour?1 bar?1, the obtained 2D Al-MOF laminar membranes exhibit rejection rates of nearly 100% on investigated inorganic ions. The simulation results confirm that intrinsic nanopores of the Al-MOF nanosheets domain the ion/water separation, and the vertically aligned aperture channels are the main transport pathways for water molecules.
| S-EPMC7274808 | biostudies-literature
Project description:Electrochemical (EC) and photoelectrochemical (PEC) water splitting represent promising strategies for renewable energy conversion and fuel production and require design of efficient catalysts for the oxygen evolution reaction (OER). Herein, we report the synthesis of two-dimensional (2D) Co-based metal organic framework (Co-MOF) nanosheets and their bifunctional catalytic properties for both EC and PEC OER. Benefiting from the large surface area and abundant isolated metal active sites, the Co-MOF nanosheets exhibited excellent OER activity and stability. The efficient electron-hole generation and separation of the nanosheets, owing to dimensional confinement, contributed to an improved visible light response in PEC OER. This study presents a new strategy to design EC/PEC bifunctional catalyst utilizing unique structural and electronic features of 2D MOF.
| S-EPMC7672199 | biostudies-literature
Project description:The preparation of a highly water stable and porous lanthanide metal-organic framework (MOF) nanoparticles (denoted SUMOF-7II; SU refers to Stockholm University) is described. SUMOF-7II was synthesized starting from the tritopic linker of 2,4,6-tri-p-carboxyphenyl pyridine (H3L2) and La(III) as metal clusters. SUMOF-7II forms a stable dispersion and displays high fluorescence emission with small variation over the pH range of 6 to 12. Its fluorescence is selectively quenched by Fe(III) ions compared to other metal ions. The intensity of the fluorescene emission drops drops linearly in 16.6-167 ?M Fe(III) concentration range, and Stern-Volmer plots are linear. The limit of detection (LOD) is 16.6 ?M (at an S/N ratio of >3). This indicator probe can also be used for selective detection of tryptophan among several amino acids. Compared to the free linker H3L2, SUMOF-7II offers improved sensitivity and selectivity of the investigated species. Graphical abstractA water-stable porous lanthanide metal-organic framework SUMOF-7II (La) has shown to be an excellent probe for the detection of ferric ions among other metal ions, and tryptophan among other amino acids in aqueous solution. The new probe displays high and stable fluorescence signal in a wide pH range (6-12).
| S-EPMC5552832 | biostudies-other
Project description:Ionic liquids (ILs) show promise as safe electrolytes for electrochemical devices. However, the conductivity of ILs decreases markedly at low temperatures because of strong interactions arising between the component ions. Metal-organic frameworks (MOFs) are appropriate microporous host materials that can control the dynamics of ILs via the nanosizing of ILs and tunable interactions of MOFs with the guest ILs. Here, for the first time, we report on the ionic conductivity of an IL incorporated within a MOF. The system studied consisted of EMI-TFSA (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide) and ZIF-8 (Zn(MeIM)2, H(MeIM) = 2-methylimidazole) as the IL and the MOF, respectively. While the ionic conductivity of bulk EMI-TFSA showed a sharp decrease arising from freezing, the EMI-TFSA@ZIF-8 showed no marked decrease because there was no phase transition. The ionic conductivity of EMI-TFSA@ZIF-8 was higher than that of bulk EMI-TFSA below 250 K. This result points towards a novel method by which to design electrolytes for electrochemical devices such as batteries that can operate at low temperatures.
| S-EPMC5707510 | biostudies-literature
Project description:The development of new catalytic nanomaterials following sustainability criteria both in their composition and in their synthesis process is a topic of great current interest. The purpose of this work was to investigate the preparation of nanocatalysts derived from the zirconium metal-organic framework UiO-66 obtained under friendly conditions and supporting dispersed species of non-noble transition elements such as Cu, Co, and Fe, incorporated through a simple incipient wetness impregnation technique. The physicochemical properties of the synthesized solids were studied through several characterization techniques and then they were investigated in reactions of relevance for environmental pollution control, such as the oxidation of carbon monoxide in air and in hydrogen-rich streams (COProx). By controlling the atmospheres and pretreatment temperatures, it was possible to obtain active catalysts for the reactions under study, consisting of Cu-based UiO-66-, bimetallic CuCo-UiO-66-, and CuFe-UiO-6-derived materials. These solids represent new alternatives of nanostructured catalysts based on highly dispersed non-noble active metals.
| S-EPMC7023304 | biostudies-literature
Project description:A novel Zn(II) metal-organic framework [Zn4O(C30H12F4O4S8)3]n, namely ZnBPD-4F4TS, has been constructed from a fluoro- and thiophenethio-functionalized ligand 2,2',5,5'-tetrafluoro-3,3',6,6'-tetrakis(2-thiophenethio)-4,4'-biphenyl dicarboxylic acid (H2BPD-4F4TS). ZnBPD-4F4TS shows a broad green emission around 520 nm in solid state luminescence, with a Commission International De L'Eclairage (CIE) coordinate at x = 0.264, y = 0.403. Since d10-configured Zn(II) is electrochemically inert, its photoluminescence is likely ascribed to ligand-based luminescence which originates from the well-conjugated system of phenyl and thiophenethio moieties. Its luminescent intensities diminish to different extents when exposed to various metal ions, indicating its potential as an optical sensor for detecting metal ion species. Furthermore, ZnBPD-4F4TS and its NH4Br-loaded composite, NH4Br@ZnBPD-4F4TS, were used for proton conduction measurements in different relative humidity (RH) levels and temperatures. Original ZnBPD-4F4TS shows a low proton conductivity of 9.47 × 10-10 S cm-1 while NH4Br@ZnBPD-4F4TS shows a more than 25,000-fold enhanced value of 2.38 × 10-5 S cm-1 at 40 °C and 90% RH. Both of the proton transport processes in ZnBPD-4F4TS and NH4Br@ZnBPD-4F4TS belong to the Grotthuss mechanism with Ea = 0.40 and 0.32 eV, respectively.
| S-EPMC8401761 | biostudies-literature
Project description:A new metal-organic coordination polymer [Zn2(sedc)2(dabco)] (1se; sedc2- = selepophene-2,5-dicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane) was synthesized and characterized by single-crystal X-ray diffraction analysis. This MOF is based on {Zn2(OOCR)4N2} paddle wheels and is isoreticular to the family of [Zn2(bdc)2(dabco)] derivatives (1b; bdc2- = 1,4-benzenedicarboxylate) with pcu topology. The gas adsorption measurements revealed that 1se shows a 15% higher CO2 volumetric uptake at 273 K and 28% higher CO2 uptake at 298 K (both at 1 bar) compared to the prototypic framework 1b. Methane and nitrogen adsorption at 273 K was also investigated, and IAST calculations demonstrated a pronounced increase in CO2/CH4 and CO2/N2 selectivity for 1se, compared with 1b. For example, the selectivity factor for the equimolar CO2/CH4 gas mixture at 1 bar = 15.1 for 1se and 11.9 for 1b. The obtained results show a remarkable effect of the presence of selenium atom on the carbon dioxide affinity in the isoreticular metal-organic frameworks with very similar geometry and porosity.
| S-EPMC7582736 | biostudies-literature
Project description:Osteochondral defects (OCD) cannot be efficiently repaired due to the unique physical architecture and the pathological microenvironment including enhanced oxidative stress and inflammation. Conventional strategies, such as the control of implant microstructure or the introduction of growth factors, have limited functions failing to manage these complex environments. Here we developed a multifunctional silk-based hydrogel incorporated with metal-organic framework nanozymes (CuTA@SF) to provide a suitable microenvironment for enhanced OCD regeneration. The incorporation of CuTA nanozymes endowed the SF hydrogel with a uniform microstructure and elevated hydrophilicity. In vitro cultivation of mesenchymal stem cells (MSCs) and chondrocytes showed that CuTA@SF hydrogel accelerated cell proliferation and enhanced cell viability, as well as had antioxidant and antibacterial properties. Under the inflammatory environment with the stimulation of IL-1β, CuTA@SF hydrogel still possessed the potential to promote MSC osteogenesis and deposition of cartilage-specific extracellular matrix (ECM). The proteomics analysis further confirmed that CuTA@SF hydrogel promoted cell proliferation and ECM synthesis. In the full-thickness OCD model of rabbit, CuTA@SF hydrogel displayed successfully in situ OCD regeneration, as evidenced by micro-CT, histology (HE, S/O, and toluidine blue staining) and immunohistochemistry (Col I and aggrecan immunostaining). Therefore, CuTA@SF hydrogel is a promising biomaterial targeted at the regeneration of OCD.
| S-EPMC9163388 | biostudies-literature