Elisa Gitzhofer

Bio: Elisa Gitzhofer is an academic researcher from University of Strasbourg. The author has contributed to research in topics: Nanoparticle & Catalysis. The author has an hindex of 2, co-authored 2 publications receiving 13 citations.

Solar Light Induced Photon-Assisted Synthesis of TiO₂ Supported Highly Dispersed Ru Nanoparticle Catalysts.

Abstract: Ru/TiO₂ are promising heterogeneous catalysts in different key-reactions taking place in the catalytic conversion of biomass towards fuel additives, biofuels, or biochemicals. TiO₂ supported highly dispersed nanometric-size metallic Ru catalysts were prepared at room temperature via a solar light induced photon-assisted one-step synthesis in liquid phase, far smaller Ru nanoparticles with sharper size distribution being synthesized when compared to the catalysts that were prepared by impregnation with thermal reduction in hydrogen. The underlying strategy is based on the redox photoactivity of the TiO₂ semi-conductor support under solar light for allowing the reduction of metal ions pre-adsorbed at the host surface by photogenerated electrons from the conduction band of the semi-conductor in order to get a fine control in terms of size distribution and dispersion, with no need of chemical reductant, final thermal treatment, or external hydrogen. Whether acetylacetonate or chloride was used as precursor, 0.6 nm sub-nanometric metallic Ru particles were synthesized on TiO₂ with a sharp size distribution at a low loading of 0.5 wt.%. Using the chloride precursor was necessary for preparing Ru/TiO₂ catalysts with a 0.8 nm sub-nanometric mean particle size at 5 wt.% loading, achieved in basic conditions for benefitting from the enhanced adsorption between the positively-charged chloro-complexes and the negatively-charged TiO₂ surface. Remarkably, within the 0.5⁻5 wt.% range, the Ru content had only a slight influence on the sub-nanometric particle size distribution, thanks to the implementation of suitable photo-assisted synthesis conditions. We demonstrated further that a fine control of the metal Ru nanoparticle size on the TiO₂ support was possible via a controlled nanocluster growth under irradiation, while the nanoparticles revealed a good resistance to thermal sintering.

Light-driven synthesis of sub-nanometric metallic Ru catalysts on TiO2

Abstract: A one-step room temperature photo-assisted synthesis has been implemented in liquid phase and under solar light for preparing highly dispersed TiO2 supported metallic Ru catalysts, with no need of final thermal treatment, external hydrogen, or chemical reductant. Whether RuCl3 chloride or Ru(acac)3 acetylacetonate precursor salt was used, sub-nanometric metallic Ru nanoparticles were synthesized on TiO2 with a sharp size distribution, the high dispersion and the metallic nature of the nanoparticles being evidenced by transmission electron microscopy and X-ray photoelectron spectroscopy. However, the use of the chloride salt was proposed to be more suitable for preparing Ru/TiO2 catalysts, due to the lower photodeposition efficiency observed with acetylacetonate, that did not allow to synthesize Ru nanoparticles with a loading higher than 1 wt.%. Different reaction mechanisms have been proposed for explaining the behaviour of both TiO2-salt systems during the Ru nanoparticle synthesis, involving respectively, both holes and electrons charge carriers in oxidation and reduction steps with acetylacetonate, and the sole photogenerated electrons with chloride.

Model reactions for the evaluation of poly- and multifunctional molecules as potential interfacial agents for the compatibilization of polyethylene/poly(ethylene-co-vinyl alcohol) blends

Abstract: Aiming an identifying an interfacial agent for polyethylene (PE)/poly(ethylene-co-vinyl alcohol) (EVOH) blends that are the main components found in flexible food packaging, triallyl isocyanurate and a molecule bearing two (2,2,6,6-tetramethylpiperidin-1-yl)oxyl...

Ru nanoclusters confined in porous organic cages for catalytic hydrolysis of ammonia borane and tandem hydrogenation reaction.

Abstract: The fabrication of narrow-sized metal nanoclusters for heterogeneous catalysis has attracted widespread research attention. Nevertheless, it is still a significant challenge to fabricate highly dispersed metal-nanocluster-based catalysts with high activity and stability. In this study, 1,3,5-benzenetricarboxylate and 1,2-diaminocyclohexane were used as precursors to fabricate porous organic cages (POCs), CC3-R. CC3-R exhibited a high specific surface area and a microporous–mesoporous structure. In addition, ultrafine Ru nanoclusters were successfully encapsulated in CC3-R with high dispersion via impregnation and subsequent reduction, affording Ru nanoclusters with a precisely controlled size of ∼0.65 nm. As-obtained Ru(1.45%)@CC3-R exhibited significantly enhanced catalytic activities toward the hydrolysis of ammonia borane (AB) and exhibited high conversion and selectivity for the tandem hydrogenation of nitroarenes and hydrogenation of quinoline in water under mild conditions. In addition, the Ru(1.45%)@CC3-R catalyst exhibited high stability and good recyclability. This study should provide a novel strategy for fabricating highly dispersed ultrafine nanocluster-based catalysts for various catalysis applications.

Crystal phase induced band gap energy enhancing the photo-catalytic properties of Zn–Fe2O4/Au NPs: experimental and theoretical studies

Abstract: Visible light assisted photo-catalysts are actively considered for the oxidation of contaminants as rapid water treatment. In this work, Au nanoparticles were grown on the surface of a ZnFe2O4 composite and used as photo-catalysts for the degradation of paracetamol. This type of deposition was chosen to enhance visible light absorption as well as to influence the 001 crystalline phase of Zn–Fe2O4 in order to reduce band-gap energy. Diffuse reflectance spectroscopy was employed to determine the band gap energy, which was then corroborated with the calculated band-gap energy (HOMO–LUMO) through the density of states using density functional theory (DFT). Furthermore, a high magnetic saturation (Ms) resulting from ZnFe2O4–Au NPs facilitated a quick recovery from the medium for reuse. The incorporation of Zn ions in the Fe sites of Fe3O4 reduced the Ms value and coercivity, considerably. However, the presence of Au NPs in Zn–Fe2O4 increased the Ms value with decreasing coercivity, exhibiting a noteworthy superparamagnetic behavior. The oxidation of paracetamol was studied under visible light using ZnFe2O4–Au NPs, showing an efficient visible light driven degradation. A first-order kinetics was observed for the substrate, for which a possible mechanism was proposed based on the DFT analysis. The surface passivation or modification of the catalyst was studied for ZnFe2O4–Au NPs by atomic force microscopy (AFM) to check whether there was any surface modification after being used for the oxidation. Interestingly, we used the 2D HPLC technique to characterize the intermediates as the separation of peaks was relatively low owing to the overlapping of peaks in the conventional HPLC method. The mechanism proposed for the oxidation is consistent with the energy profile of intermediates that resulted from the DFT studies. The interaction of all the materials with Saccharomyces cerevisiae cells was investigated for the development of green bio-imaging signals from ZnFe2O4–Au NPs.

Advances In The Chemistry of The Coordination Compounds

Abstract: basic scientific contributions in the field of pharmacology. This volume covers 15 scientific subjects of major interest. The basic scientific principles of pharmacology rather than the use of drugs as therapeutic agents is stressed throughout. The introductory chapter by Gaddum tracing the growth of pharmacology in Edinburgh is followed by the highlights of pharmacology in China, India and Central Europe. These brief reviews are entirely inadequate and serve only to give adequate bibliographies of the original papers. Chapters are included on the biochemical aspects of drug action, structure-activity relationships, mechanisms of drug absorption and excretion with reference to the central nervous system, drug biotransformation, nervous transmission in the invertebrates, parasite chemotherapy, central depressants, renal pharmacology and pharmacological control of adrenal and gonadal secretion. Maickel and Weissbach discuss the relatively new techniques of spectrophotofluorometry, gas-liquid chromatography and tritium gas exposure labeling and have compiled a useful list of references regarding chemical and biochemical assay techniques. The review of reviews by Chauncey Leake is highly recommended. The editors of this book are to be congratulated for this valuable addition to current pharmacological literature. This volume is a collection of 76 papers and lectures presented by participants from 17 nations at the Proceedings of the Sixth International Conference on Coordination Chemistry held at Wayne State University in the summer of 1961. Approximately half of these papers are of a purely physical-chemical nature and often do little more than present tables of raw experimental data. Very little effort is made to correlate these experimental results with broader aspects of coordination chemistry which is, after all, the main value of such a conference. Furthermore, there is no apparent order to the presentation of the papers and the general effect is that of a bound collection of articles chosen at random from the chemical literature. In spite of these shortcomings, there are many pearls of interesting information scattered throughout the pages of this book. A useful reference work could have resulted if an exhaustive subject index had been included. The lack of any subject index whatsoever seems inexcusable. The Ciba Foundation and the Editors are to be congratulated for publishing yet one more of their stimulating symposia which will be widely read. The symposium is divided into two parts. The first part, in which papers were presented and discussions held before an invited audience, involves current problems in theoretical pharmacology, such as enzymes as primary points …

Carbon-based ruthenium nanomaterial-based electroanalytical sensors for the detection of anticancer drug Idarubicin.

Abstract: In this work, a novel nanosensing platform was suggested based on ruthenium for the sensitive determination of Idarubicin anticancer drugs. Ruthenium/Vulcan carbon-based nanoparticles were synthesized ultrasonication method and then characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The mean particle size of the nanoparticles calculated by the TEM analysis was found to be 1.98 nm ± 0.29 nm, and the Ru nanoparticles were mostly dispersed on the support material. Glassy carbon electrode (GCE) surface was modified with Ruthenium/Vulcan carbon-based nanomaterials (Ru@VC), and characterization of the nanosensor was performed using electrochemical impedance spectroscopy and cyclic voltammetry. The limit of detection (LOD) and limit of quantification (LOQ) values were found as 9.25 × 10–9 M and 2.8 × 10–8 M in buffer samples. To demonstrate the applicability and validity of developed nanosensor, it was used for the determination of Idarubicin in Idamen® IV (10 mg/10 mL vial) and human serum sample. The results of recovery studies showed that the Ru@VC/GCE nanosensor was free from excipient interferences in the dosage forms of injection, and it can be successfully applied to biological samples.

Experimental and Theoretical Advances on Single Atom and Atomic Cluster‐Decorated Low‐Dimensional Platforms towards Superior Electrocatalysts

Abstract: The fundamental relationship between structure and properties, which is called “structure‐property”, plays a vital role in the rational designing of high‐performance catalysts for diverse electrocatalytic applications. Low‐dimensional (LD) nanomaterials, including 0D, 1D, 2D materials, combined with low‐nuclearity metal atoms, ranging from single atoms to subnanometer clusters, are currently emerging as rising star nanoarchitectures for heterogeneous catalysis due to their well‐defined active sites and unbeatable metal utilization efficiencies. In this work, a comprehensive experimental and theoretical review is provided on the recent development of single atom and atomic cluster‐decorated LD platforms towards some typical clean energy reactions, such as water‐splitting, nitrogen fixation, and carbon dioxide reduction reactions. The upmost attractive structural properties, advanced characterization techniques, and theoretical principles of these low‐nuclearity electrocatalysts as well as their applications in key electrochemical energy devices are also elegantly discussed.