Instantaneous formation of polyoxometalate-based cerium vanadium oxide gels

et al.The instantaneous formation of mechanically stable cerium vanadium oxide gels starting from soluble polyoxovanadates is reported together with initial application studies. Upon addition of phosphoric acid to solutions containing a vanadium oxide source (e.g. (nBuN)[VO]) and Ce, instantaneous formation (reaction time <1 s) of a vanadium oxide gel is observed. The gel shows unique mechanical and thermal stabilities (up to ∼180 °C). High permeability of the gel is observed, allowing its use for long-term acid delivery into aqueous media or for the adsorption of organic aromatic dye pollutants from solution. A range of spectroscopy and electron microscopy techniques provide insight into the gel formation and the gel composition: an intertwined 3D matrix of nanowires (d ∼ 10 nm) containing cerium, vanadium oxide and phosphate is identified as an inorganic matrix which enables the formation of the mechanically stable gel.Financial support by the Deutscher Akademischer Austauschdienst (DAAD) EU COST Action CM1203, Ulm University, Friedrich-Alexander-Universität Erlangen-Nürnberg and Fundación General CSIC (Programa ComFuturo) is gratefully acknowledged.Peer Reviewe

Alkoxy-functionalized ionic liquid electrolytes: Understanding ionic coordination of calcium ion speciation for the rational design of calcium electrolytes

There is growing interest in the rational design of electrolytes for multivalent-ion batteries by tuning the molecular-level interactions of solvate species present in the electrolytes. Herein, we report our effort to control Ca-ion speciation in ionic liquid (IL) based electrolytes through the design of alkoxy-functionalized cations. Quantitative analysis reveals that the alkoxy-functionalized ammonium cation (N$_{07}$$^{+}$), bearing seven ether oxygen atoms, can effectively displace the bis(trifluoromethanesulfonyl)imide anion (TFSI$^{-}$) from the Ca$^{2+}$ ion coordination sphere, facilitating the reversible Ca deposition/stripping process. More importantly, post-analysis of Ca deposits surface chemistry and density functional theory calculations of Ca-ion speciation indicate the formation of an organic-rich, but inorganic-poor solid electrolyte interphase layer, which enables Ca$^{+2}$ ion diffusion rather than passivating the Ca metal electrode. Finally, as a proof-of-concept, a prototype Ca/V$_{2}$O$_{5}$ cell using the optimized IL-based electrolyte ([Ca(BH$_{4}$)$_{2}$]$_{0.05}$ [N$_{07}$TFSI]$_{0.95}$) is demonstrated for the first time, exhibiting a remarkable initial discharge capacity of 332 mA h g$^{-1}$ and reversible capacity of 244 mA h g$^{-1}$

Novel Polyoxometalate- Ionic Liquid with Antibacterial and Antifungal Properties. Feasibility of Its Implementation As a Multifunctional Thin Coating

The synthesis of hybrid materials, combining the properties of organic and inorganic components, results in composites with unique physical and chemical features. Polyoxometalates (POMs), i.e. inorganic anionic molecular metal oxides, are considered as promising future metallodrugs due to their antiviral, antitumoral and antibacterial activities. The combination of bulky organic cations with POMs results in composite ionic liquids (IL; melting point below 100°C) which combine the unique properties of both components. Pioneering studies have used composites of alkylammonium cations and POM anions for multifunctional water purification to remove toxic heavy materials, organic aromatics and microbes and for the inhibition of bio-corrosion on metal and stone surfaces due to coating formation.Fil: Enderle, Ana Gabriela. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Streb, C.. Universitat Ulm; AlemaniaFil: Bollini, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Culzoni, Maria Julia. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Química. Cátedra de Química Analítica; ArgentinaFil: Mitchell, S. G.. Universidad de Zaragoza; EspañaFil: Franco Castillo, I.. Universidad de Zaragoza; España2019 AIChE Annual MeetingOrlandoEstados UnidosAmerican Institute of Chemical Engineer

Evaluating the durability and performance of polyoxometalate-ionic liquid coatings on calcareous stones: Preventing biocolonisation in outdoor environments

Rock-based materials exposed to outdoor environments are naturally colonised by an array of microorganisms, which can cause dissolution and fracturing of the natural stone. Biocolonisation of monuments and architectures of important cultural heritage therefore represents an expensive and recurring problem for local authorities and private owners alike. In this area, preventive strategies to mitigate biocolonisation are generally preferred to curative approaches, such as mechanical cleaning by brush or high-pressure cleaning, to remove pre-existing patina. The aim of this work was to study the interaction between biocidal polyoxometalate-ionic liquid (POM-IL) coatings and calcareous stones and evaluate the capacity of these coatings to prevent biocolonisation through a series of accelerated ageing studies in climate chambers, carried out in parallel with a two-year period of outdoor exposure in north-eastern France. Our experiments show that POM-IL coatings did not affect water vapour transfer nor significantly alter the total porosity of the calcareous stones. Simulated weathering studies replicating harsh (hot and wet) climatic weather conditions demonstrated that the colour variation of POM-IL-coated stones did not vary significantly with respect to the natural uncoated stones. Accelerated biocolonisation studies performed on the weathered POM-IL-coated stones proved that the coatings were still capable of preventing colonisation by an algal biofilm. However, a combination of colour measurements, chlorophyll fluorescence data, and scanning electron microscopy imaging of stones aged outdoors in northern France for two years showed that coated and uncoated stone samples showed signs of colonisation by fungal mycelium and phototrophs. Altogether, our results demonstrate that POM-ILs are suitable as preventative biocidal coatings for calcareous stones, but the correct concentrations must be chosen to achieve a balance between porosity of the stone, the resulting colour variation and the desired duration of the biocidal effect over longer periods of time, particularly in outdoor environments

New protective coatings against lampenflora growing in the Pommery Champagne cellar

Phototrophic microorganisms such as cyanobacteria and microalgae can proliferate readily in underground heritage sites where the introduction of artificial illumination equipment has significantly altered previously stable environmental conditions. The extended lampenflora biofilm growth on the bas-reliefs carved in the underground Pommery Champagne cellar in Reims (France) represents a recurring biocolonisation problem which requires periodic cleaning. The aim of this work was to limit the growth of lampenflora on chalk substrates using preventative biocidal treatments based on polyoxometalate ionic liquids (POM-ILs). Biocidal assays carried out in laboratory showed how two different colourless POM-IL coatings were more effective than commercial Preventol RI80 against two algal strains isolated from the Pommery bas reliefs, Pseudostichococcus monallantoides and Chromochloris zofingiensis. However, only one POM-IL variant was capable of sustained prevention of biofilm growth when applied to wet chalk, which replicates the more drastic natural environmental conditions of the cellar and can limit the performance of the biocidal coatings. Crucially, coating concentration studies demonstrate how POM-IL-coated slabs from previous experiments retain their biocidal activity and can prevent subsequent recolonisation following the re-inoculation of coated slabs with algae and cyanobacteria. Consequently, POM-ILs represent excellent candidates to eliminate lampenflora growth on the chalk bas-reliefs in the unique subterranean environment of the Pommery Champagne cellar. © 2022 The Author

Supramolecular activation of a molecular photocatalyst

The effects of the planar aromatic organic molecules anthracene and pyrene on the catalytic performance of the intramolecular hydrogen evolving photocatalyst [Ru(tbbpy)2(tpphz)PdCl2](PF6)2 functioning as a photocatalytic dyad have been studied. 1H-NMR studies on [Ru(tbbpy)2(tpphz)PdCl2](PF6)2 and [Ru(tbbpy)2(tpphz)](PF6)2 show a pronounced interaction of pyrene with the ruthenium complexes due to π–π-interactions. The solid state structure of [Ru(tbbpy)2(tpphz)PdCl2]2[Mo8O24] shows a pronounced π–π-stacking of the polyaromatic ligands. In addition, dimerization constants for the complexes and association constants between the complexes and pyrene were determined. Studies on the photocatalytic hydrogen production show a decreased induction phase and increased turn over frequencies during the initial phase of the catalysis in the presence of anthracene and pyrene utilising the catalyst [Ru(tbbpy)2(tpphz)PdCl2](PF6)2 irrespective of the nature of the polycyclic aromatic hydrocarbon

Determinants of the Development of Corporate Bond Markets in Argentina: One Size Does Not Fit All

Conventional theory leads to expect bonds to be a financing vehicle for large firms because of economies of scale and contracting costs. We find both in our econometric evidence for firms quoted on Latin American stock exchanges, and in our survey results for Argentina, that size of assets is a robust determinant of the use of bond finance. This result, together with the fact that there are few firms that are large in terms of market value, can help understand why Argentina, as well as Latin America, has small bond markets in terms of the ratio of the stock of bonds to GDP. Since firm value represents the present value of the cash flows against which the firm borrows, the outstanding stock of corporate bonds is as small as the size of Argentine firms

Role of psychiatric hospitals during a pandemic: introducing the Munich Psychiatric COVID-19 Pandemic Contingency Plan

BACKGROUND Psychiatry is facing major challenges during the current coronavirus disease 2019 (COVID)-19 pandemic. These challenges involve its actual and perceived role within the medical system, in particular how psychiatric hospitals can maintain their core mission of attending to people with mental illness while at the same time providing relief to overstretched general medicine services. Although psychiatric disorders comprise the leading cause of the global burden of disease, mental healthcare has been deemphasised in the wake of the onslaught of the pandemic: to make room for emergency care, psychiatric wards have been downsized, clinics closed, psychiatric support systems discontinued and so on. To deal with this pressing issue, we developed a pandemic contingency plan with the aim to contain, decelerate and, preferably, avoid transmission of COVID-19 and to enable and maintain medical healthcare for patients with mental disorders. AIMS To describe our plan as an example of how a psychiatric hospital can share in providing acute care in a healthcare system facing an acute and highly infectious pandemic like COVID-19 and at the same time provide support for people with mental illness, with or without a COVID-19 infection. METHOD This was a descriptive study. RESULTS The plan was based on the German national pandemic strategy and several legal recommendations and was implemented step by step on the basis of the local COVID-19 situation. In addition, mid- and long-term plans were developed for coping with the aftermath of the pandemic. CONCLUSIONS The plan enabled the University Hospital to maintain medical healthcare for patients with mental disorders. It has offered the necessary flexibility to adapt its implementation to the first and second waves of the COVID-19 pandemic in Germany. The plan is designed to serve as an easily adaptable blueprint for psychiatric hospitals around the world