Search

Industrial development and urbanization have increased the emission of Volatile Organic Compounds (VOCs) into the atmosphere, causing environmental and health risks. Several approaches are used for their abatement, including chemical, thermo‐ and photo‐catalytic oxidations, but they are not fully satisfactory. In this work, a thermoplastic TiO2‐based photo‐catalyst was used as a coating layer of a glass‐reactor. Solar‐triggered photocatalytic degradation of ethanol, toluene, and acetone (used as model VOCs) highlights the better performance of the coated photoreactor than that of TiO2 nanopowder. The influence of the pollutant flow rate on the photodegradation performance of the system was also investigated, revealing an inverse relationship between degradation and flow rates. The experimental data suggest that our approach provides a cost‐effective and efficient way to boost the abatement of VOCs, useful for further industrial‐scale applications. The morphology and the compositional homogeneity of the nanocomposite coating were addressed through Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X‐ray Analysis. [ABSTRACT FROM AUTHOR]

Lead is one of the key metals of the all-inorganic lead halide perovskites. This work tailors novel architectures of lead's coordination sphere using a β-diketone (H-hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione) and a glyme (monoglyme, diglyme, triglyme, or tetraglyme) ligand. The coordination chemistry and thermal behaviour of these "Pb(hfa)2·glyme" adducts have been analysed through FT-IR spectroscopy, 1H and 13C NMR analyses, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Single-crystal X-ray diffraction studies provide evidence of the formation of a monomeric Pb(hfa)2·monoglyme structure. In order to validate the potentiality of these "Pb(hfa)2·glyme" precursors for the fabrication of Pb-based halide perovskites, a facile, one-step and low-temperature solution approach has been applied to prepare CsPbBr3 microcrystals with a process carried out in air under atmospheric pressure. Pure stoichiometric CsPbBr3 powders, obtained using Cs(hfa) and Br2 as cesium and bromide sources, respectively, show excellent stability under atmospheric conditions. Better results are obtained in terms of yield and stability from the diglyme and tetraglyme lead adducts. Field emission scanning electron microscopy (FE-SEM) indicates a good uniform morphology of cubic grains, while the structure and the 1 : 1 : 3 stoichiometry of Cs : Pb : Br are confirmed by X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX), respectively. Tauc plots derived from absorption spectroscopy point to optical energy band-gaps (Eg) in the 2.21–2.27 eV range, in agreement with literature data. The present research elucidates the potential of these novel "Pb(hfa)2·glyme" adducts as promising lead precursors for CsPbBr3 perovskite synthesis, paving the way for their implementation in various technological applications. [ABSTRACT FROM AUTHOR]

In the present work, an in-depth study on the sol-gel process for the fabrication of Eu-doped CaF2 materials in the form of thin films has been addressed for the production of down-shifting layers. Fine-tuning of the operative parameters, such as the annealing temperature, substrate nature and doping ion percentage, has been finalized in order to obtain Eu(III)-doped CaF2 thin films via a reproducible and selective solution process for down-shifting applications. An accurate balance of such parameters allows for obtaining films with high uniformity in terms of both their structural and compositional features. The starting point of the synthesis is the use of a mixture of Ca(hfa)2•diglyme•H2O and Eu(hfa)3•diglyme adducts, with a suited ratio to produce 5%, 10% and 15% Eu-doped CaF2 films, in a water/ethanol solution. A full investigation of the structural, morphological and compositional features of the films, inspected using X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX), respectively, has stated a correlation between the annealing temperature and the structural characteristics and morphology of the CaF2 thin films. Interestingly, crystalline CaF2 films are obtained at quite low temperatures of 350–400 °C. The down-shifting properties, validated by taking luminescence measurements under UV excitation, have allowed us to correlate the local environment in terms of the degree of symmetry around the europium ions with the relative doping ion percentages. [ABSTRACT FROM AUTHOR]

Nanocomposites obtained by the decoration of graphene-based materials with silver nanoparticles (AgNPs) have received increasing attention owing to their antimicrobial activity. However, the complex synthetic methods for their preparation have limited practical applications. This study aims to synthesize novel NanoHybrid Systems based on graphene, polymer, and AgNPs (namely, NanoHy-GPS) through an easy microwave irradiation approach free of reductants and surfactants. The polymer plays a crucial role, as it assures the coating layer/substrate compatibility making the platform easily adaptable for a specific substrate. AgNPs' loading (from 5% to 87%) can be tuned by the amount of Silver salt used during the microwave-assisted reaction, obtaining spherical AgNPs with average sizes of 5–12 nm homogeneously distributed on a polymer-graphene nanosystem. Interestingly, microwave irradiation partially restored the graphene sp2 network without damage of ester bonds. The structure, morphology, and chemical composition of NanoHy-GPS and its subunits were characterized by means of UV-vis spectroscopy, thermal analysis, differential light scattering (DLS), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray analysis (EDX), Atomic Force Microscopy (AFM), and High-Resolution Transmission Electron Microscopy (HRTEM) techniques. A preliminary qualitative empirical assay against the typical bacterial load on common hand-contacted surfaces has been performed to assess the antibacterial properties of NanoHy-GPS, evidencing a significative reduction of bacterial colonies spreading. [ABSTRACT FROM AUTHOR]