Cu and Zn promoted Al-fumarate metal organic frameworks for electrocatalytic CO reduction.

Metal organic frameworks (MOFs) are attractive materials to generate multifunctional catalysts for the electrocatalytic reduction of CO to hydrocarbons. Here we report the synthesis of Cu and Zn modified Al-fumarate (Al-fum) MOFs, in which Zn promotes the selective reduction of CO to CO and Cu promotes CO reduction to oxygenates and hydrocarbons in an electrocatalytic cascade. Cu and Zn nanoparticles (NPs) were introduced to the Al-fum MOF by a double solvent method to promote in-pore metal deposition, and the resulting reduced Cu-Zn@Al-fum drop-cast on a hydrophobic gas diffusion electrode for electrochemical study.

Silver and Copper Nitride Cooperate for CO Electroreduction to Propanol.

The need of carbon sources for the chemical industry, alternative to fossil sources, has pointed to CO as a possible feedstock. While CO electroreduction (CO R) allows production of interesting organic compounds, it suffers from large carbon losses, mainly due to carbonate formation. This is why, quite recently, tandem CO R, a two-step process, with first CO R to CO using a solid oxide electrolysis cell followed by CO electroreduction (COR), has been considered, since no carbon is lost as carbonate in either step.

Development and Characterization of Innovative Multidrug Nanoformulation for Cardiac Therapy.

For several decades, various peptides have been under investigation to prevent ischemia/reperfusion (I/R) injury, including cyclosporin A (CsA) and Elamipretide. Therapeutic peptides are currently gaining momentum as they have many advantages over small molecules, such as better selectivity and lower toxicity. However, their rapid degradation in the bloodstream is a major drawback that limits their clinical use, due to their low concentration at the site of action.

CO Electroreduction in Water with a Heterogenized C-Substituted Nickel Cyclam Catalyst.

Molecular catalysis for selective CO electroreduction into CO can be achieved with a variety of metal complexes. Their immobilization on cathodes is required for their practical implementation in electrolytic cells and can benefit from the advantages of a solid material such as easy separation of products and catalysts, efficient electron transfer to the catalyst, and high stability. However, this approach remains insufficiently explored up to now.

Selective Ethylene Production from CO and CO Reduction via Engineering Membrane Electrode Assembly with Porous Dendritic Copper Oxide.

Gas-fed zero-gap electrolyzers have recently emerged as attractive systems for limiting ohmic losses and costs associated with electrolytes and for optimizing energy efficiencies. Here, we report that using a dendritic Cu oxide (D-CuO) material deposited on a gas diffusion layer as the cathode of a gas-fed zero-gap membrane electrode assembly (MEA) system results in a very selective conversion of CO to ethylene. More specifically, CO reduction yielded ethylene with an FE up to 68% at 100-125 mA·cm with H as the only other gaseous product and the electrolysis could be carried out for several hours with good stability.

EPS for bacterial anti-adhesive properties investigated on a model metal surface.

Understanding Extracellular Polymeric Substances (EPS) interaction on a well-defined chromium surface is of importance especially for biocorrosion processes. Adsorption of EPS extracted from Pseudoalteromonas NCIMB 2021 on Cr surfaces was investigated using in situ quartz crystal microbalance (QCM) and X-ray photoelectron spectroscopy (XPS). We show that EPS adsorption is an irreversible process.

Early stage of marine biofilm formation on duplex stainless steel.

The aim of this work was to investigate the bacteria-surface interactions occurring during the first hour of adhesion of marine Pseudoalteromonas NCIMB 2021 at the surface of 2304 lean duplex stainless steel in artificial seawater. A complete characterization of the biofilm and the passive film was performed coupling epifluorescence microscopy, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time of flight secondary ion mass spectrometry (ToF-SIMS). The coupling of XPS and ToF-SIMS analyses revealed that (1) protein and polysaccharide contents in the biofilm are similar in the presence or absence of nutrients, (2) the biofilm is mainly composed of proteins and the protein content is similar to the one of Tightly Bound EPS, (3) increased bacterial activity due to nutrients leads to chromium enrichment in the passive film in close vicinity to the bacteria.

Carbon-Nanotube-Supported Copper Polyphthalocyanine for Efficient and Selective Electrocatalytic CO Reduction to CO.

Electroreduction of CO to CO is one of the simplest ways to valorise CO as a source of carbon. Herein, a cheap, robust, Cu-based hybrid catalyst consisting of a polymer of Cu phthalocyanine coated on carbon nanotubes, which proved to be selective for CO production (80 % faradaic yield) at relatively low overpotentials, was developed. Polymerisation of Cu phthalocyanine was shown to have a drastic effect on the selectivity of the reaction because molecular Cu phthalocyanine was instead selective for proton reduction under the same conditions.

Electroreduction of CO on Single-Site Copper-Nitrogen-Doped Carbon Material: Selective Formation of Ethanol and Reversible Restructuration of the Metal Sites.

It is generally believed that CO electroreduction to multi-carbon products such as ethanol or ethylene may be catalyzed with significant yield only on metallic copper surfaces, implying large ensembles of copper atoms. Here, we report on an inexpensive Cu-N-C material prepared via a simple pyrolytic route that exclusively feature single copper atoms with a CuN coordination environment, atomically dispersed in a nitrogen-doped conductive carbon matrix. This material achieves aqueous CO electroreduction to ethanol at a Faradaic yield of 55 % under optimized conditions (electrolyte: 0.

Boron Nitride as a Novel Support for Highly Stable Palladium Nanocatalysts by Atomic Layer Deposition.

The ability to prepare controllable nanocatalysts is of great interest for many chemical industries. Atomic layer deposition (ALD) is a vapor phase technique enabling the synthesis of conformal thin films and nanoparticles (NPs) on high surface area supports and has become an attractive new route to tailor supported metallic NPs. Virtually all the studies reported, focused on Pd NPs deposited on carbon and oxide surfaces.

Local Degradation Mechanisms by Tarnishing of Protected Silver Mirror Layers Studied by Combined Surface Analysis.

In this work, we addressed the local degradation mechanisms limiting the prelaunch environmental durability of thin-layered silver stacks for demanding space mirror applications. Local initiation and propagation of tarnishing were studied by combined surface and interface analysis on model stack samples consisting of thin silver layers supported on lightweight SiC substrates and protected by thin SiO overcoats, deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous HS. The results show that tarnishing is locally initiated by the formation of AgS columns erupting above the stack surface.

A Dendritic Nanostructured Copper Oxide Electrocatalyst for the Oxygen Evolution Reaction.

To use water as the source of electrons for proton or CO reduction within electrocatalytic devices, catalysts are required for facilitating the proton-coupled multi-electron oxygen evolution reaction (OER, 2 H O→O +4 H +4 e ). These catalysts, ideally based on cheap and earth abundant metals, have to display high activity at low overpotential and good stability and selectivity. While numerous examples of Co, Mn, and Ni catalysts were recently reported for water oxidation, only few examples were reported using copper, despite promising efficiencies.

Effects of molybdenum on the composition and nanoscale morphology of passivated austenitic stainless steel surfaces.

Surface analysis by time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy and scanning tunnelling microscopy has been applied to provide new insight on Mo effects on the composition and nanostructure of the passive films grown in sulfuric acid on well-controlled Fe-17Cr-14.5Ni-2.3Mo(100) austenitic stainless steel single crystal surfaces.

The influence of the electrolyte on chemical and morphological modifications of an iron sulfide thin film negative electrode.

The chemical and morphological modifications of FeS thin film as anode material for LiBs have been studied in detail in two classical electrolytes usually used in Li-ion batteries: 1 M LiClO4-PC and 1 M LiPF6-EC/DMC. The X-ray photoelectron spectroscopic (XPS) analysis evidenced the formation of a solid electrolyte interphase (SEI) that contains a more significant amount of inorganic salt residues formed in LiPF6-EC/DMC than in LiClO4-PC, which is likely to increase the ionic resistivity of the SEI, thus impeding the lithiation-delithiation in the first cycles while improving its reversibility. Ion depth profiles performed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) show volume expansion-shrinkage of the thin film leading to cracking and pulverization of the electrode material, which is also confirmed by scanning electron microscopy (SEM) analysis.

Aging-induced chemical and morphological modifications of thin film iron oxide electrodes for lithium-ion batteries.

Spectroscopic (XPS, ToF-SIMS) and microscopic (SEM, AFM) analytical methods have been applied to iron oxide (∼Fe2O3) using a thin film approach to bring new insight into the aging mechanisms of conversion-type anode materials for lithium-ion batteries. The results show that repeated lithiation/delithiation causes both chemical and morphological modifications affecting the electrochemical performance. The SEI layer formed by reductive decomposition of the electrolyte remains stable in composition (mostly Li2CO3) but irreversibly thickens upon multicycling.

Effect of protein adsorption on the corrosion behavior of 70Cu-30Ni alloy in artificial seawater.

Copper alloys often used in cooling circuits of industrial plants can be affected by biocorrosion induced by biofilm formation. The objective of this work was to study the influence of protein adsorption, which is the first step in biofilm formation, on the electrochemical behavior of 70Cu-30Ni (wt.%) alloy in static artificial seawater and on the chemical composition of oxide layers.

Real-time investigation of the muco-adhesive properties of Lactococcus lactis using a quartz crystal microbalance with dissipation monitoring.

This work was devoted to probe, at the entire population level, interactions between mucins and Lactococcus lactis, using QCM-D. Real-time monitoring of adsorption on polystyrene of PGM (Pig Gastric Mucin) and subsequent adhesion of L. lactis was performed for IBB477 and MG1820 strains.

Long-circulating perfluorooctyl bromide nanocapsules for tumor imaging by 19FMRI.

PLGA-PEG nanocapsules containing a liquid core of perfluorooctyl bromide were synthesized by an emulsion-evaporation process and designed as contrast agents for (19)F MRI. Physico-chemical properties of plain and PEGylated nanocapsules were compared. The encapsulation efficiency of PFOB, estimated by (19)F NMR spectroscopy, is enhanced when using PLGA-PEG instead of PLGA.

Influence of surface charge on the potential toxicity of PLGA nanoparticles towards Calu-3 cells.

Background: Because of the described hazards related to inhalation of manufactured nanoparticles, we investigated the lung toxicity of biodegradable poly (lactide-co-glycolide) (PLGA) nanoparticles displaying various surface properties on human bronchial Calu-3 cells.

Methods: Positively and negatively charged as well as neutral nanoparticles were tailored by coating their surface with chitosan, Poloxamer, or poly (vinyl alcohol), respectively. Nanoparticles were characterized in terms of size, zeta potential, and surface chemical composition, confirming modifications provided by hydrophilic polymers.

Probing in vitro interactions between Lactococcus lactis and mucins using AFM.

This work was devoted to the first AFM investigation of the adhesion force to pig gastric mucin (PGM) using Lactococcus lactis as the model for lactic acid bacteria. The PGM coating on polystyrene was characterized using a complementary set of multiscale analytical methods, including AFM (HarmoniX mode), XPS, and the sessile drop method. The PGM layer, which was mainly composed of C-O, C-N, COOH, CONH, and sulfur-related species (protein core and oligosaccharide side chains), was quite homogeneous and hydrophilic, with an estimated thickness of 3.

Evaluation of adhesion force between functionalized microbeads and protein-coated stainless steel using shear-flow-induced detachment.

Spherical microbeads functionalized with two types of chemical groups (NH(2), OH) were chosen as a simplified bacterial model, in order to elucidate the role of macromolecular interactions between specific biopolymers and 316 L stainless steel, in the frame of biofilm formation in the marine environment. NH(2) microbeads were used in their native form or after covalent binding to BSA or different representative poly-amino acids. OH microbeads were used in their native form.

Covalent immobilization of lysozyme on stainless steel. Interface spectroscopic characterization and measurement of enzymatic activity.

A new strategy aiming at the protection of metallic surfaces against the growth of biofilms is presented here. This work reports the grafting of primary amines by aminosilanization of oxidized stainless steel followed by chemical coupling of the glycosidase lysozyme from hen egg white using glutaraldehyde as homobifunctional cross-linking agent. Controlled characterization of a stainless steel surface by X-ray photoelectron spectroscopy and Fourier transform infrared reflection-absorption spectroscopy at each step enabled the mode of binding, coverage, and orientation of the grafted molecules to be addressed.

Self-assembling of atomic vacancies at an oxide/intermetallic alloy interface.

Oxide layers grown on the surface provide an effective way of protecting metallic materials against corrosion for sustainable use in a broad range of applications. However, the growth of cavities at the metal/oxide interface weakens the adherence of the protective layer and can promote its spallation under service conditions, as observed for alumina layers formed by selective oxidation of aluminide intermetallic alloys used in high-temperature applications. Here we show that direct atomic-scale observations of the interface between an ultrathin protective oxide layer (alumina) grown on an intermetallic titanium aluminide substrate (TiAl) can be performed with techniques sensitive to the topmost atomic layers at the surface.