Synthesis of Ni-poor NiO nanoparticles for DSSC-p applications

International audienceOver the last decade, p-type semiconductors (SC) have known a renewed interest. Indeed these materials may have potentialapplications for light-emitting diodes, transistors, solar cells, etc. Since the achievement of the first Dye Sensitized Solar Cells (DSSC) by Grätzel in 1991 a new generation of solar cells has been developed where the n-type SC is replaced by a p-type one. This leads to the photo-injection of holes instead of electrons in the circuit. To date nickel oxide (NiO) is the reference p-type semiconductor.However yields are still far from those of n-DSSC and many studies aim to replace NiO by other systems such as CuAlO2 , CuGaO2,CuCrO2 or NiCo2O4 nanoparticles. Following our recent synthesis of N doped ZnO with stabilization of p-type charge carriers, wefocus now on the preparation of N doped NiO nanoparticles to improve the p-type conductivity of NiO. We study here the chemicalreactivity of a nickel oxyhydroxide precursor under air and ammonia that conducts to nanostructured Ni-poor NiO

Metabolic processes and carbon nutrient exchanges between host and pathogen sustain the disease development during sunflower infection by Sclerotinia sclerotiorum.

International audienceInteractions between the necrotrophic fungus Sclerotinia sclerotiorum and one of its hosts, Helianthus annuus L., were analyzed during fungal colonization of plant tissues. Metabolomic analysis, based on (13)C- and (31)P-NMR spectroscopy, was used to draw up the profiles of soluble metabolites of the two partners before interaction, and to trace the fate of metabolites specific of each partner during colonization. In sunflower cotyledons, the main soluble carbohydrates were glucose, fructose, sucrose and glutamate. In S. sclerotiorum extracts, glucose, trehalose and mannitol were the predominant soluble carbon stores. During infection, a decline in sugars and amino acids was observed in the plant and fungus total content. Sucrose and fructose, initially present almost exclusively in plant, were reduced by 85%. We used a biochemical approach to correlate the disappearance of sucrose with the expression and the activity of fungal invertase. The expression of two hexose transporters, Sshxt1 and Sshxt2, was enhanced during infection. A database search for hexose transporters homologues in the S. sclerotiorum genome revealed a multigenic sugar transport system. Furthermore, the composition of the pool of reserve sugars and polyols during infection was investigated. Whereas mannitol was produced in vitro and accumulated in planta, glycerol was exclusively produced in infected tissues and increased during colonization. The hypothesis that the induction of glycerol synthesis in S. sclerotiorum exerts a positive effect on osmotic protection of fungal cells and favors fungal growth in plant tissues is discussed. Taken together, our data revealed the importance of carbon-nutrient exchanges during the necrotrophic pathogenesis of S. sclerotiorum

Structural phase transition in IrTe2_2: A combined study of optical spectroscopy and band structure calculations

Ir$_{1-x}$Pt$_x$Te$_2$ is an interesting system showing competing phenomenon between structural instability and superconductivity. Due to the large atomic numbers of Ir and Te, the spin-orbital coupling is expected to be strong in the system which may lead to nonconventional superconductivity. We grew single crystal samples of this system and investigated their electronic properties. In particular, we performed optical spectroscopic measurements, in combination with density function calculations, on the undoped compound IrTe$_2$ in an effort to elucidate the origin of the structural phase transition at 280 K. The measurement revealed a dramatic reconstruction of band structure and a significant reduction of conducting carriers below the phase transition. We elaborate that the transition is not driven by the density wave type instability but caused by the crystal field effect which further splits/separates the energy levels of Te (p$_x$, p$_y$) and Te p$_z$ bands.Comment: 16 pages, 5 figure

Preparation of nitrogen doped zinc oxide nanoparticles and thin films by colloidal route and low temperature nitridation process

International audienceNitrogen doped zinc oxide (ZnO) nanoparticles have been synthesized using a colloidal route and low temperature nitridation process. Based on these results, 200 nm thick transparent ZnO thin films have been prepared by dip-coating on SiO2 substrate from a ZnO colloidal solution. Zinc peroxide (ZnO2) thin film was then obtained after the chemical conversion of a ZnO colloidal thin film by H2O2 solution. Finally, a nitrogen doped ZnO nanocrystalline thin film (ZnO:N) was obtained by ammonolysis at 250°C. All the films have been characterized by scanning electron microscopy, X-ray diffraction, X-Ray photoelectron spectroscopy and UV-Visible transmittance spectroscopy

Synthesis of Ni-poor NiO nanoparticles for p-DSSC applications

International audienceTo improve the performances of p-Dye Sensitized Solar Cell (p-DSSC) for the future, the synthesis of modified p-type nickel oxide semiconductor, commonly used as photocathode in such devices, was initiated with Ni3O2(OH)4 as precursor. This specific nickel oxyhydroxide was first characterized by X-ray photo-electron spectroscopy and magnetic susceptibility measurements. Then its thermal decomposition was thoroughly studied in order to control the particles size of the as-prepared NiO nanopowders. Low temperature decomposition in air of this precursor allows the formation of Ni1-xO nanoparticles with a large amount of Ni vacancies and specific surface areas up to 250 m2.g-1. Its ammonolysis at 250°C leads to nanostructured N-doped NiO (NiO:N) materials

QENS and the benefit of diffusion measurements over different length scales

The quasi-elastic neutron scattering (QENS) technique was first used to derive self-diffusivities of hydrocarbons in zeolites, but transport diffusivities of deuterated molecules and of molecules which do not contain hydrogen atoms can now be measured. The technique allows to probe diffusion over length scales ranging from an Å to hundreds of Å. The mechanism of diffusion can thus be followed from the elementary jumps between adsorption sites to Fickian diffusion. Since the space and time scales of the neutron techniques match closely the ones covered by molecular simulations, one expects, and usually finds, good agreement between neutrons and simulations. The neutron data give therefore reference values, so that lower values obtained by other techniques measuring diffusion over longer length scales have to be explained by additional transport barriers

Proactive Leadership Attention to Outcomes

Abstract Category: Practice Innovation / Evidence-Based Practice Purpose: The purpose of this initiative was to implement evidence-based rounding in the Intensive Care Unit to decrease CLABSI rates to zero, and maintain zero CAUTI incidences; to empower staff to be proactive versus reactive; to increase staff awareness of hospital acquired infection risks and criteria; to reinforce current bundle compliance and alternatives to lines and catheters; and to obtain “real time results” related to high risk patients. Methods: Biweekly rounds were designed evaluating necessity, management and documentation of patients with central access and urinary catheters. Rounds were conducted by: Clinical RN Project lead, Chief Nursing Officer; Chief Medical Officer; Director of ICU; ICU Clinical Educator; Infection Control Practitioner; and Director of QI/PI. Nurses caring for targeted patients prepared a PLATO rounding checklist prior to rounding. The PLATO team rounded with unit staff and leadership to go through checklist. Findings: In the four months prior to the PLATO intervention, the average CLABSI rate in the ICU was 3.37. In the three months post-PLATO intervention, the ICU CLABSI rate has remained at zero. The CAUTI rate in the ICU has also been maintained at zero. Discussion: Through the proactive collaborative intentional rounding with clinical nurses, quality department personnel, and executive and unit leadership, patient outcomes were positively affected in the ICU patient population. Implications for Practice: Collaborative intentional rounding has positive implications for patient outcomes. Opportunities for improvement were identified, that could impact catheter-related infections such as: the management of glucose, alternatives to line and catheter (midlines and external catheter use), and the utilization of mupirocin in new central lines and review of indications of urinary catheter reinsertion. Opportunities also exist to expand the outcomes measured beyond CAUTI and CLABSI, such as ventilator-assisted pneumonia. When implemented, the effects of proactive leadership rounding can impact patient outcomes positively

Proactive Leadership Attention to Outcomes

Abstract Category: Practice Innovation / Evidence-Based Practice Purpose: The purpose of this initiative was to implement evidence-based rounding in the Intensive Care Unit to decrease CLABSI rates to zero, and maintain zero CAUTI incidences; to empower staff to be proactive versus reactive; to increase staff awareness of hospital acquired infection risks and criteria; to reinforce current bundle compliance and alternatives to lines and catheters; and to obtain “real time results” related to high risk patients. Methods: Biweekly rounds were designed evaluating necessity, management and documentation of patients with central access and urinary catheters. Rounds were conducted by: Clinical RN Project lead, Chief Nursing Officer; Chief Medical Officer; Director of ICU; ICU Clinical Educator; Infection Control Practitioner; and Director of QI/PI. Nurses caring for targeted patients prepared a PLATO rounding checklist prior to rounding. The PLATO team rounded with unit staff and leadership to go through checklist. Findings: In the four months prior to the PLATO intervention, the average CLABSI rate in the ICU was 3.37. In the three months post-PLATO intervention, the ICU CLABSI rate has remained at zero. The CAUTI rate in the ICU has also been maintained at zero. Discussion: Through the proactive collaborative intentional rounding with clinical nurses, quality department personnel, and executive and unit leadership, patient outcomes were positively affected in the ICU patient population. Implications for Practice: Collaborative intentional rounding has positive implications for patient outcomes. Opportunities for improvement were identified, that could impact catheter-related infections such as: the management of glucose, alternatives to line and catheter (midlines and external catheter use), and the utilization of mupirocin in new central lines and review of indications of urinary catheter reinsertion. Opportunities also exist to expand the outcomes measured beyond CAUTI and CLABSI, such as ventilator-assisted pneumonia. When implemented, the effects of proactive leadership rounding can impact patient outcomes positively

Application of Inelastic Neutron Scattering to the Methanol-to-Gasoline Reaction Over a ZSM-5 Catalyst

Inelastic neutron scattering (INS) is used to investigate a ZSM-5 catalyst that has been exposed to methanol vapour at elevated temperature. In-line mass spectrometric analysis of the catalyst exit stream confirms methanol-to-gasoline chemistry, whilst ex situ INS measurements detect hydrocarbon species formed in/on the catalyst during methanol conversion. These preliminary studies demonstrate the capability of INS to complement infrared spectroscopic characterisation of the hydrocarbon pool present in/on ZSM-5 during the MTG reaction

MIL-91(Ti), a small pore metal-organic framework which fulfils several criteria : an upscaled green synthesis, excellent water stability, high CO2 selectivity and fast CO2 transport

The research leading to these results has received funding from the European Community Seventh Framework Program (FP7/2007-2013) [grant agreement number 608490] (project M4CO2) and from the ANR ‘CHESDENS’ (ANR-13-SEED-0001-01).A multidisciplinary approach combining advanced experimental and modelling tools was undertaken to characterize the promises of a small-pore type Ti-based metal-organic framework, MIL-91(Ti) for CO2 capture. This material was prepared using two synthesis strategies, i.e. under hydrothermal conditions and under reflux, and its single component adsorption behaviour with respect to CO2, CH4 and N2 was first revealed by gravimetry measurements. This hydrophilic and highly water stable MOF is characterized by a relatively high CO2 adsorption enthalpy. Molecular simulations combined with in situ powder X-ray diffraction evidenced that this is due to the combined interaction of this probe with N-H and P-O groups in the phosphonate linker. High CO2 selectivities in the presence of either N2 or CH4 were also predicted and confirmed by co-adsorption measurements. The possibility to prepare this sample under reflux represents an environmentally friendly route which can easily be upscaled. This green synthesis route, excellent water stability, high selectivities and relatively fast transport kinetics of CO2 are significant points rendering this sample of utmost interest for CO2 capture.PostprintPostprintPeer reviewe