Institut Charles Gerhardt Montpellier

Advanced fluorinated proton‐conducting membrane are dominating functional macromolecules due to their high performance in electrochemical energy devices. However, the co‐ion leakage and low power densities still proposes a challenge. Herein, a novel functionally tailored polyvinylidene fluoride‐co‐(γ)‐sulfopropyl acrylate (PVDF‐g‐SA) based proton‐conducting membrane is prepared for vanadium redox flow batteries (VRFBs). The approach introduces a facile guideline to design halato‐telechelic −SO3H architectures by tethering γ‐sulfopropyl acrylate onto dehydrofluorinated PVDF. The optimized PVDF‐g‐SA‐15 exhibits proton conductivity (κmH+) of 17 mS cm⁻¹ (akin Nafion: ~19 mS cm⁻¹) and retained 87 % and >95 % of its properties in Fenton's reagent and 3 M H2SO4, respectively. In VRFB device, the PVDF‐g‐SA‐15 shows ∼98 % capacity utilization outperforming Nafion‐117 (∼85 %). Moreover, bearing dense ionic orientation (viz AFM phases), the potential drop rate is ~2× lower for PVDF‐g‐SA‐15 (1.4×10⁻³ V min⁻¹) than that of Nafion‐117 (2.6×10⁻³ V min⁻¹). Operational endurance is evaluated fit for 150 mA cm⁻² showing maximum coulombic, energy and voltage efficiencies of >98 %, ∼78 %, ∼80 %, respectively. Further investigation for ~200 cycles infer excellent durability with ∼95 % property retention. Additionally, the PVDF‐g‐SA‐15 can deliver ~20 % higher power density than Nafion‐117 does. Thus, the revealed alternate membrane holds promising utility in VRFB applications.

A time resolved in situ X‐ray powder diffraction study using synchrotron radiation allowed for describing the evolution of the zeolite FAU structure during the development of a zeolite‐templated carbon (ZTC) in its porous voids. During the ZTC formation the intensity decrease of most zeolite reflections and the simultaneous rise in intensity of the 222 reflection (of null intensity in the pristine zeolite) was observed. Full pattern profile fitting by Rietveld refinement allowed for achieving a detailed description of the underlying chemistry, with coincident pore filling with carbon atoms in specific positions and framework distortion. Monitoring the intensity profiles of the 222 reflection allowed assessment of the energetics of the ZTC formation. Our results contribute to a better understanding of the phenomena involved on the atomic scale in ZTC synthesis.

We have studied 2‐(2‐aminophenyl)benzothiazole and related derivatives for their photophysical properties in view of employing them as new and readily tunable organic photocatalysts. Their triplet energies were estimated by DFT calculations to be in the range of 52–57 kcal mol⁻¹, suggesting their suitability for the [2+2] photocycloaddition of unsaturated acyl imidazoles with styrene derivatives. Experimental studies have shown that 2–(2–aminophenyl)benzothiazoles comprising alkylamino groups (NHMe, NHⁱPr) or the native amino group provide the best photocatalytic results in these visible‐light mediated [2+2] reactions without the need of any additives, yielding a range of cyclobutane derivatives. A combined experimental and theoretical approach has provided insights into the underlying triplet‐triplet energy transfer process.

Albeit mechanochemistry is a novel promising technology that give access to reactivity under solvent‐free conditions, heating such reactions is sometimes compulsory to obtain satisfactory results in terms of conversion, selectivity and/or yield. In this work, we developed a novel approach using a dye that absorbs NIR photons and release the energy as heat. Hence, de novo milling jars in epoxy resin doped with the dye were thus produced to obtain reactors that would produce heat upon irradiation at 850 nm. Temperature profiles were recorded, depending on the irradiance, dye charge in the resin, and milling frequency, showing an excellent control of the temperature. The usefulness of the heating jar was then demonstrated in mechanochemical reactions that are known to require heat to yield the desired product, namely Diels‐Alder reactions with high activation energies and the newly developed rearrangement of a sydnone into corresponding 1,3,4‐oxadiazolin‐2‐one.

Precise hydrogen sorting from purge gas (H2/N2) and coke gas (H2/CH4), commonly carried out by cryogenic distillation, still suffers from low separation efficiency, high energy consumption, and considerable capital cost. Though still in its infancy, membrane technology offers a potential to achieve more efficient hydrogen purification. In this study, an optimum separation of hydrogen towards both methane and nitrogen via a kinetically‐driven mechanism is realized through preferred orientation control of a MOF membrane. Relying on the 0.3 nm‐sized window aligned vertical to the substrate, b‐oriented Ti‐MOF membrane exhibits ultra‐high hydrogen selectivity, surpassing the upper bound limit of separating H2/N2 and H2/CH4 gas pairs attained so far by inorganic membranes. This spectacular selectivity is combined with a high H2 permeability owing to the synergistic effect of the 1 nm‐sized MOF channel.

Cerium oxide, or ceria, (CeO2) is one of the most studied materials for its wide range of applications in heterogeneous catalysis and energy conversion technologies. The key feature of ceria is the remarkable oxygen storage capacity linked to the switch between Ce4+ and Ce3+ states, in turn creating oxygen vacancies. Changes in the electronic structure occur with oxygen removal from the lattice. Accordingly, the two valence electrons can be accommodated by the reduction of support cations where the electrons can be localized in empty f states of Ce4+ ions nearby. Quantifying the different oxidation states in situ is crucial to understand and model the reaction mechanism. Beside the different techniques to quantify Ce3+ and Ce4+ states, we discuss the use of X‐ray Raman Scattering (XRS) spectroscopy as an alternative method. In particular, we show that XRS can observe the oxidation state changes of cerium directly in the bulk of the materials under realistic environmental conditions. The Hilbert++ code is used to simulate the XRS spectra and quantify accurately the Ce3+ and Ce4+ content. These results are compared to those obtained from in situ X‐ray Diffraction (XRD) collected in parallel and the differences arising from the two different probes are discussed.

The 5-Hydroxymethylfurfural (HMF) platform molecule can be derived from biomass feedstocks and catalytically hydrogenated into various added-value molecules. Its conversion to 5-methylfurfural (5-MF), a versatile synthetic intermediate and perfuming agent, is particularly challenging, the selective hydrodeoxygenation of the C–OH group in HMF being by far less favourable kinetically and thermodynamically than the hydrogenation of the C=O group that gives 2,5-bis-hydroxymethylfuran (BHMF). Herein, for the first time we showed that Ni/TiO2 catalysts can be tuned to promote the selective removal of a hydroxy group in the presence of an aldehyde moiety, and give high 5-MF yield. Among various synthesis approaches, the direct ion exchange incorporation of Ni into a TiO2 network prepared by an alginate synthesis route allowed the key-factors orientating the reaction selectivity towards 5-MF to be identified. The highest 5-MF selectivity (86%) at nearly full conversion was favoured by high acidity and ultra-high dispersion of Ni atoms at the surface, while the prime role of titania was discussed. By contrast, increasing the reduction temperature up to 700°C strongly lowered the acidity and formed larger Ni particles, which favour the C=O activation, and is thereby promoting the selectivity switch towards BHMF at 86% also at nearly full conversion.

Organophosphorus compounds are fundamental for the chemical industry due to their broad applications across multiple sectors, including pharmaceuticals, agrochemicals, and materials science. Despite their high importance, the sustainable and cost‐effective synthesis of organophoshoryl derivatives remains very challenging. Here, we report the first successful regio‐ and stereoselective hydrophosphorylation of terminal allenamides using an affordable copper catalyst system. This reaction offers an efficient protocol for the synthesis of (E)‐allylic organophosphorus derivatives from various types of P‐nucleophiles, such as H‐phosphonates, H‐phosphinates, and secondary phosphine oxides. Key advantages of this ligand‐free and atom‐economic strategy include low toxicity of the Cu‐based catalyst, cost effectiveness, mild reaction conditions, and experimental simplicity, making it competitive with methods that use toxic and expensive Pd‐based catalysts. In an effort to comprehend this process, we conducted extensive DFT calculations on this system to uncover the mechanistic insights of this process.

Developing energy‐ and time‐efficient strategies to derive high‐performance non‐precious electrocatalysts for anodic oxygen evolution reaction (OER), especially stably working at industrial‐demanding current density, is still a big challenge. In this work, a concise molten salt erosion scenario was devised to rapidly modulate the smooth surface of the commercial NiMo foam substrate into the rough, electronically coupled, and hierarchically porous Ni/Fe/Mo(oxy)hydroxide catalyst layer assembled by the nanosphere array. This self‐supported catalyst is super‐hydrophilic for the alkaline electrolyte and distinguished by a balanced Mo leaching/surface‐readsorption process to tune the metal d band center and electronic perturbation. The altered electronic environment with the favored OER intermediate adsorption behavior attains the outstanding OER activity in terms of a very small overpotential of 230.21 mV at 10 mA cm⁻² and an ultra‐long stability for 1179.45 h to sustain the initial commercial‐level current density of ca. 1000 mA cm⁻². This superb performance transcends most of the edge‐cutting transition metal peers reported recently and can satisfy the standards of industrial applications. This industrial‐compatible synthesis technology holds profound implications for hydrogen production via water splitting and other electrochemical applications.

The synthesis of supported multielement transition metal phosphides (TMPs) to exploit the synergistic interplay between electronic and geometric effects resulting from the presence of different metals in the material and the arrangement of heterogeneous atoms is pivotal for reducing metal content while offering multiple active sites. However, the integration of Ni, Co, and P, for example, into a nanostructured carbon network to develop self‐supporting NixCoyP bimetallic phosphides is limited by several factors, including the synthesis and the discrepancy between the crystal structure of the respective monometallic phosphides. Moreover, conventional synthesis of supported TMPs often separates nanoparticles, support and phosphidation steps, which do not allow tailoring of physical and catalytic properties via particle support, electronic and geometric interactions. Herein, an innovative solid‐state, ex situ phosphidation‐free approach tailored to synthesize a library of self‐supporting NixCoyP TMPs in N,S,P‐modified nanostructured carbon networks generated together with NixCoyP particles is presented. Extensive multivariate characterization validates the unique properties of NixCoyP bimetallic materials with enhanced electrocatalytic performance for the hydrogen evolution reaction and the selective electroconversion of biomass‐derived 5‐hydroxymethylfurfural (5‐HMF) to value‐added 2,5‐furandicarboxylic acid (FDCA) with 90–100% Faradaic efficiency. Overall, the synthesis expands the possibilities for tailoring the microstructure of supported TMPs for improved physical/catalytic properties.

With the rapid increase in temperatures around the planet, the need to develop efficient means to reduce CO2 emissions has become one of the greatest challenges of the scientific community. Many different strategies are being studied worldwide, one of which consists in trapping the gas into porous materials, either for its short- or long-term capture and storage, or its re-use for the production of value-added compounds. Yet, to further the development of such systems, there is a real need to fully understand their structure and properties, including at the molecular-level following the physisorption and/or chemisorption of CO2 (which can lead to various species, including carbonate and bicarbonate ions). In this context, 17O NMR naturally appears as the analytical tool of choice, because of its exquisite sensitivity to probe subtle differences in oxygen bonding environments. To date, it has scarcely been used, due to the very low natural abundance of 17O (0.04%), and the absence of commercially available 17O-labeled compounds adapted to such investigations (e.g., 17O-CO2(g), or 17O-enriched Na- and K- (bi)carbonate salts, which can be readily transformed into CO2). Herein, we demonstrate how, using mechanochemistry, it is possible to enrich with 17O a variety of Na- and K- (bi)carbonate salts in a fast, economical, scalable, and user-friendly way. The high enrichment levels enabled recording the first high-resolution 17O ssNMR spectra of these phases at different temperatures and magnetic fields. From these, the typical spectral signatures of (bi)carbonate ions could be obtained, showing their strong sensitivity to local dynamics. Lastly, we show how thanks to the selective 17O-labeling, singular aspects of the reactivity of carbonates in materials can be unveiled using in-situ 17O ssNMR. In the long run, it is expected that this work will open the way to more profound investigations of the structure and properties of carbon capture and storage systems, and, more generally speaking, of functional materials containing carbonates.

Mastering of analytical methods for accurate quantitative determinations of enantiomeric excess is a crucial aspect in asymmetric catalysis, chiral synthesis, and pharmaceutical applications. In this context, the phenomenon of Self‐Induced Diastereomeric Anisochronism (SIDA) can be exploited in NMR spectroscopy for accurate determinations of enantiomeric composition, without using a chiral auxiliary that could interfere with the spectroscopic investigation. This phenomenon can be particularly useful for improving the quantitative analysis of mixtures with low enantiomeric excesses, where direct integration of signals can be tricky. Here, we describe a novel analysis protocol to correctly determine the enantiomeric composition of scalemic mixtures and investigate the thermodynamic and stereochemical features at the basis of SIDA. Dipeptide derivatives were chosen as substrates for this study, given their central role in drug design. By integrating the experiments with a conformational stochastic search that includes entropic contributions, we provide valuable information on the dimerization thermodynamics, the nature of non‐covalent interactions leading to self‐association, and the differences in the chemical environment responsible for the anisochronism, highlighting the importance of different stereochemical arrangement and tight association for the distinction between homochiral and heterochiral adducts. An important role played by the counterion was pointed out by computational studies.

We report silicon carbide (SiC) based epoxidation catalysts constituted of a silicon carbide core and a silica/titania (SiO2/TiO2) shell. The catalysts were obtained via surface modification of SiC microparticles and...

The engineering of conjugated oligo- and polymers at the micro- and nanoscale is crucial for developing advanced functional materials and electronic devices, such as OFETs, OLEDs, and sensors, due to their electronic and optoelectronic properties being highly dependent on their supramolecular order. This research investigates the self-assembly and aggregation behavior of a series of amphiphilic oligothiophenes with varying hydrophilic/hydrophobic balances, synthesized through palladium-catalyzed cross-coupling reactions. The molecular structures were characterized using NMR and mass spectrometry, and their optical properties were examined by UV-Visible absorption spectroscopy, revealing distinct absorption maxima influenced by the molecular architecture. Dynamic light scattering (DLS) and cryotransmission electron microscopy (cryo-TEM) studies demonstrated the formation of spherical aggregates with diameters around 200 nm in aqueous solutions, consistent with scattering measurements indicating low critical micelle concentrations (cmc). Adsorption isotherms and Brewster Angle Microscopy (BAM) highlighted the interfacial properties and interactions of these amphiphilic molecules at air/water interface, emphasizing the impact of their structural features on self-assembly and material properties. These findings underscore the potential of amphiphilic oligothiophenes in tuning solution self-assembly, morphology, and optoelectronic characteristics for applications in advanced electronic materials.

Organic photovoltaic (OPV) cells are commonly produced by successive printing of four layers on top of a transparent conducting electrode, with the active layer sandwiched in between interlayers followed by the top electrode. Here, the simplification of OPV manufacturing without the need to coat a hole transport layer (HTL) in inverted OPV (n–i–p) is reported. To ensure the required hole selectivity, thermally trigged molecules are directly blended in the active layer during device casting. Following thermal annealing of the complete devices, organosulfur molecules self‐assembled to form a hole–transporting interface between the silver top electrode and the active layer, thereby enabling working devices. Device optimization is performed by varying the concentration of these molecules and the thermal annealing conditions. The performances of the simplified devices approach those of control devices with vacuum‐evaporated MoO3 HTLs. The solar cells exhibit very encouraging thermal and photostabilities. This work opens the route to high efficiency, simplified, and low‐cost organic solar cells.

Precise hydrogen sorting from purge gas (H2/N2) and coke gas (H2/CH4), commonly carried out by cryogenic distillation, still suffers from low separation efficiency, high energy consumption, and considerable capital cost. Though still in its infancy, membrane technology offers a potential to achieve more efficient hydrogen purification. In this study, an optimum separation of hydrogen towards both methane and nitrogen via a kinetically‐driven mechanism is realized through preferred orientation control of a MOF membrane. Relying on the 0.3 nm‐sized window aligned vertical to the substrate, b‐oriented Ti‐MOF membrane exhibits ultra‐high hydrogen selectivity, surpassing the upper bound limit of separating H2/N2 and H2/CH4 gas pairs attained so far by inorganic membranes. This spectacular selectivity is combined with a high H2 permeability owing to the synergistic effect of the 1 nm‐sized MOF channel.

Halocarbons have important industrial applications, but because of their contribution to global warming and the fact that they can cause ozone depletion, they are considered highly toxic. Hence, the techniques that can capture and recover the used halocarbons with energy‐efficient methods have been recently received greater attention. In this contribution, we report the capture of dichlorodifluoromethane (R12), which has high global warming and ozone depletion potential, using covalent organic polymers (COPs). The defect‐engineered COPs were synthesized and demonstrated outstanding sorption capacities, ~226 wt % of R12 combined with linear‐shaped adsorption isotherms. We further identified the plausible microscopic adsorption mechanism of the investigated COPs via grand canonical Monte Carlo simulations applied to non‐defective and a collection of atomistic models of the defective COPs. The modeling work suggests that significant R12 adsorption performance is attributed to a gradual increment of porosities due to isolated/interconnected micro‐/meso‐pore channels and the change of the long‐range ordering of both COPs. The successive hierarchical‐pore‐filling mechanism promotes R12 molecular adsorption via moderate van der Waals adsorbate‐adsorbent interactions in the micropores of both COPs at low pressure followed by adsorbate‐adsorbate interactions in the extra‐voids created at moderate to high pressure ranges. This continuous pore‐filling mechanism makes defective COPs as promising sorbents for halocarbon adsorption.

Enantiopure α‐hydroxyphosphonates represent an important class of organophosphorus compounds that have gained considerable attention due to their diverse biological and synthetic applications. This review provides a comprehensive overview of enantioselective methods for the synthesis of chiral α‐hydroxyphosphonates, covering the literature from 1983 to February 2024. It details the main synthetic strategies, notably the asymmetric hydrophosphonylation of carbonyl compounds, the asymmetric reduction of α‐ketophosphonates, and α,β‐phosphonoenolates. In addition, the review examines the strenghts and limitations of each method, providing detailed insights into reaction conditions, substrate scope, and enantiomeric excesses. image