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Herein we report a hybrid organic–inorganic nanomaterial that combines the structural stability of colloidal lignin nanoparticles with the lubricant performance of MoS2 nanoparticles.

Green chemistry letters and reviews 15(3), 658-670 (2022). doi:10.1080/17518253.2022.2125352, Published by Taylor and Francis, London [u.a.]

Climate change, triggered by a continuously rising use of carbon based energy sources, is a global concern. Geological hydrogen storage, e.g. in depleted gas fields or saline aquifers, can overcome imbalances between supply and demand in the renewable energy sector and facilitate the transition to a low carbon emissions society, in this way mitigating climate change. However, a range of subsurface microorganisms utilise hydrogen which may have important implications for hydrogen recovery, clogging and corrosion. We created a novel, globally applicable risk categorization tool based on the published environmental growth constraints of all major hydrogen utilizing microbes (hydrogenotrophic methanogens, hydrogenotrophic sulphate reducing bacteria, homoacetogens and hydrogenotrophic dissimilative iron reducing bacteria) and on reports of paleosterile subsurface environments. Application of the tool to 75 depleted or close to depleted gas fields on the UK continental shelf showed that 9 fields fall either within the ´No Risk´ category with temperatures >122 °C, making them the ideal candidates for hydrogen storage from a microbial risk point of view. Hydrogen storage in the 35 ´Low Risk´ fields with temperatures >90 °C or the 22 ´Medium Risk´ fields with temperatures >55 °C and salinities >1.7 M NaCl will require the careful characterization of the microbial community composition to assure that hydrogenotrophic microorganisms are not present. We recommend against utilising depleted gas fields with temperatures

The development of sustainable valorization methods for lignin is a challenging task, because the vast majority of the reported methods require either harsh conditions or the use of expensive transition metal catalysts. Inspired from the natural-sunlight degradation of lignin, known as lignin yellowing, we report here the use of a commercially available cheap organic photocatalyst, namely, phenacyl bromide (PAB), for the efficient cleavage of lignin model compound 2-phenoxyacetophenone (2-PAP), and the depolymerization of soda pulped lignin (SL) under UV-A irradiation under ambient conditions. Real-time NMR investigations of the photoreaction between the model compound and PAB shed light on the possible reaction mechanisms involving different radical species, HBr, and molecular oxygen. Interestingly, combined spectral, chromatographic, powder X-ray diffraction and thermal studies of the photocatalytic reaction between PAB and SL indicated the formation of guaiacyl alcohol. The unprecedented catalytic performance of such a simple organic photocatalyst is attributed to the generation of phenacyl radicals, photolabile brominated species and HBr playing key roles in the cleavage of β-O-4 linkages. This study represents a new edge for lignin valorization under mild reaction conditions and offers the opportunity for large-scale environment-neutral production of valuable aromatics using technical lignins as feedstock.

RSC Advances 12(50), 32318-32326 (2022). doi:10.1039/D2RA04663F, Published by RSC Publishing, London

Ruthenium containing molecular electrocatalyst onto pyridine modified, fluorine-doped carbon cloth represents an efficient, bifunctional, and regenerable electrode for water electrolysis at pH 7.

Our results yield evidence of a large lake environment that existed near the ancient site of Olympia which was so far unknown. The limnic sequence reveals considerable changes in the ecological conditions over time, based on Direct Push sensing, sedimentary and micropalaeontological analyses. Radiocarbon data show that the “Lake of Olympia“ existed from the 8th/7th millennium BC until, at least, the 1st century AD. The existence of the “Lake of Olympia” next to the cult site of Olympia has considerable historical, archaeological and geographical implications (e.g., as waterway or water supplier).

Direct hydroxylation via the functionalization of tertiary benzylic C(sp(3))-H bonds is of great significance for obtaining tertiary alcohols, which find wide applications in pharmaceuticals as well as in fine chemical industries. However, current synthetic procedures use toxic reagents, and therefore, the development of a sustainable strategy for the synthesis of tertiary benzylic alcohols is highly desirable. To solve this problem, herein, we report a metal-free heterogeneous photocatalyst to synthesize the hydroxylated products using oxygen as the key reagent. Various benzylic substrates were employed into our mild reaction conditions to afford the desirable products in good to excellent yields. More importantly, the gram-scale reaction was achieved via harvesting direct solar energy and exhibited high quantity of the product. The high stability of the catalyst was proved via recycling the catalyst and spectroscopic analyses. Finally, a possible mechanism was proposed based on electron paramagnetic resonance and other experimental evidence.

This mini-review focuses on up-to-date advances of hybrid materials consisting of organic and inorganic components and their applications in different chemical processes. The purpose of forming such hybrids is mainly to functionalize and stabilize inorganic supports by attaching an organic linker to enhance their performance towards a target application. The interface chemistry is present with the emphasis on the sustainability of their components, chemical changes in substrates during synthesis, improvements of their physical and chemical properties, and, finally, their implementation. The latter is the main sectioning feature of this review, while we present the most prosperous applications ranging from catalysis, through water purification and energy storage. Emphasis was given to materials that can be classified as green to the best in our consideration. As the summary, the current situation on developing hybrid materials as well as directions towards sustainable future using organic-inorganic hybrids are presented.

We report the first magic-angle spinning (MAS) nuclear magnetic resonance (NMR) study on Sn(NCN). In this compound the spatially elongated (NCN)2− ion is assumed to develop two distinct forms: either cyanamide (N≡C–N2−) or carbodiimide (−N=C=N−). Our 14N MAS NMR results reveal that in Sn(NCN) the (NCN)2− groups exist exclusively in the form of symmetric carbodiimide ions with two equivalent nitrogen sites, which is in agreement with the X-ray diffraction data. The 14N quadrupolar coupling constant | C Q | $\vert {C}_{\text{Q}}\vert $ ≈ 1.1 MHz for the −N=C=N− ion in Sn(NCN) is low when compared to those observed in molecular compounds that comprise cyano-type N≡C– moieties ( | C Q | $\vert {C}_{\text{Q}}\vert $ > 3.5 MHz). This together with the information from 14N and 13C chemical shifts indicates that solid-state NMR is a powerful tool for providing atomic-level insights into anion species present in these compounds. The experimental NMR results are corroborated by high-level calculations with quantum chemistry methods.

Quaternary transition metal cyanamides Na

Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions. The high stability of OLNPs is attributed to the alkyl chains accumulated in the shell of the particle, which delays protonation/deprotonation of carboxylic acid and phenolic hydroxyl groups. Owing to the enhanced stability, acid‐ and base‐catalyzed functionalization of OLNPs at pH 2.0 and pH 12.0 via oxirane ring‐opening reactions were successfully performed. We also demonstrated these new functionalized particles as efficient pH‐switchable dye adsorbents and anticorrosive particulate coatings., Lignin oleate nanoparticles (OLNPs) are demonstrated for functionalization in aqueous dispersion under acidic (pH 2) and basic (pH 12) conditions owing to the hydration barrier effect provided by oleic acid chains in the shells of OLNPs. Covalent functionalization of these nanoparticles using robust chemistries opens new avenues such as functional anticorrosive coatings and pH‐switchable adsorbents for removal of organic dyes from wastewater.

BackgroundThe constant growth of interest in hybrid coronary artery revascularization (HCR) is apparent. Yet, few studies report outcomes of the one-stage HCR. Consequently, the status of such procedures is not adequately supported in clinical guidelines. The aim of this study was to report the safety, feasibility, and long term-outcomes of the one-stage HCR.Methods and resultsPatients were enrolled in the prospective one-stage hybrid coronary revascularization program (HYBRID-COR). They underwent a one-stage hybrid revascularization procedure while on double antiplatelet therapy (DAPT) with Ticagrelor: endoscopic atraumatic coronary artery bypass grafting (EACAB) for revascularization of the left anterior descending (LAD) artery and percutaneous intervention in non-LAD arteries with contemporary drug-eluting stents. The composite primary endpoint included MACCE (major adverse cardiac and cerebrovascular events: death, myocardial infarction, stroke, and repeated revascularization) in long-term observation. The study cohort consisted of 30 patients (68% male) with stable coronary artery disease (26.7%) and unstable angina (73.3%). Procedural success was 100%. No death, myocardial infarction (MI), or stroke were observed in the perioperative period. One patient (3.3%) required chest revision and blood transfusion due to surgical bleeding. Kidney injury was noted in two patients (6.6%). In a long-term follow-up (median; IQR: 4.25; 2.62–4.69 years), two patients (6.6%) underwent repeated revascularization and one patient (3.3%) died due to MI. The overall primary endpoint rate was 9.9%.ConclusionOne-stage hybrid revascularization, on DAPT, is a feasible, safe, and efficient way of achieving complete revascularization in selected patients. The complication rate is low and acceptable. Further randomized trials are required.

Phosphor-converted white light emitting diodes (pc-LEDs) are efficient light sources for applications in lighting and electronic devices. Nitrides, with their wide-ranging applicability due to their intriguing structural diversity, and their auspicious chemical and physical properties, represent an essential component in industrial and materials applications. Here, we present the successful adsorption of Eu and Tb at the grain boundaries of bulk β-Si

Breaking down lignin into smaller units is the key to generate high value-added products. Nevertheless, dissolving this complex plant polyphenol in an environment-friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin-derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti-corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass-based solvent, a straightforward approach to produce high value-added compounds or tailored biobased materials was demonstrated.

The ability of mimicking the extracellular matrix architecture has gained electrospun scaffolds a prominent space into the tissue engineering field. The high surface-to-volume aspect ratio of nanofibers increases their bioactivity while enhancing the bonding strength with the host tissue. Over the years, numerous polyesters, such as poly(lactic acid) (PLA), have been consolidated as excellent matrices for biomedical applications. However, this class of polymers usually has a high hydrophobic character, which limits cell attachment and proliferation, and therefore decreases biological interactions. In this way, functionalization of polyester-based materials is often performed in order to modify their interfacial free energy and achieve more hydrophilic surfaces. Herein, we report the preparation, characterization, and in vitro assessment of electrospun PLA fibers with low contents (0.1 wt %) of different curcuminoids featuring π-conjugated systems, and a central β-diketone unit, including curcumin itself. We evaluated the potential of these materials for photochemical and biomedical purposes. For this, we investigated their optical properties, water contact angle, and surface features while assessing their in vitro behavior using SH-SY5Y cells. Our results demonstrate the successful generation of homogeneous and defect-free fluorescent fibers, which are noncytotoxic, exhibit enhanced hydrophilicity, and as such greater cell adhesion and proliferation toward neuroblastoma cells. The unexpected tailoring of the scaffolds' interfacial free energy has been associated with the strong interactions between the PLA hydrophobic sites and the nonpolar groups from curcuminoids, which indicate its role for releasing hydrophilic sites from both parts. This investigation reveals a straightforward approach to produce photoluminescent 3D-scaffolds with enhanced biological properties by using a polymer that is essentially hydrophobic combined with the low contents of photoactive and multifunctional curcuminoids.

Zeitschrift für Naturforschung / B 76(5), 275-280 (2021). doi:10.1515/znb-2021-0031, Published by De Gruyter, Berlin

The growing interest in gene therapy is coupled with the strong need for the development of safe and efficient gene transfection vectors. A composite based on chitosan and fumed silica has been found to be a prospective gene delivery carrier. This study presents an investigation of the nature of the bonds between a series of nucleotides with a chitosan layer deposited on a fumed silica surface. Experimentally measured surface complex formation constants (logK) of the nucleotides were found to be in the range of 2.69-4.02, which is higher than that for the orthophosphate (2.39). Theoretically calculated nucleotide complexation energies for chitosan deposited on the surface range from 11.5 to 23.0 kcal.mol(-)(1), in agreement with experimental data. The adsorption of nucleotides was interpreted using their calculated speciation in an aqueous solution. Based on the structures of all optimized complexes determined from quantum-chemical PM6 calculations, electrostatic interactions between the surface-located NH3- groups and -PO3H--/-PO32- fragments of the nucleotides were identified to play the decisive role in the adsorption mechanism. The saccharide fragment of monophosphates also plays an important role in the binding of the nucleotides to chitosan through the creation of hydrogen bonds.

Inorganic chemistry 60(2), 919-929 (2021). doi:10.1021/acs.inorgchem.0c03041, Published by American Chemical Society, Washington, DC

Lubrication of an internal combustion engine is critical for energy and material losses. Engine lubricants contain a number of functional additives including zinc dialkyldithiophosphate, which is a...

Monitoring suspended sediment transported in fluvial systems is of major importance regarding natural hazards, water quality, and sustainable river management. However, monitoring is challenged by the spatial and temporal variability of suspended sediment transport and thus time consuming and costly. Here we analyze the spatial variability of suspended sediment in the German waterways using data from suspended monitoring networks of the German water and shipping authority (WSV). The data consists of four stations with cross-sectional measurements (isokinetic sampling with 20-25 samples/sampling campaign and 3-4 campaigns per cross-section/year) along with three stations with frequent (daily) point measurements. As the distribution of SSC with water depth is well established through the Rouse profile, uncertainties are induced through the determination of the settling velocity and the assumption of suspended sediment being transported as primary particles.The lateral and vertical variability are quantified through the mean standard deviation for each vertical profile and sampling depth for each sampling campaign respectively. First, we investigate general patterns (including the vertical and lateral variability) of suspended sediment concentration (SSC) in the four different cross-sections. Second, we link the lateral and vertical variability with discharge, the magnitude of SSC, and flow velocity. Third, we estimate differences between the cross-sectional sampling and single point sampling.Our preliminary results indicate an increase of vertical and lateral variability with average SSC in the cross-section. This involves a strong vertical gradient at high average SSC and increased variability at the bottom compared to near-surface SSC. As the flow velocity is smaller at the bottom, we detect a decrease in variability with higher flow velocity. These general patterns are present at each cross-section. However, site specific variations are abundant; caused by site specific properties, such as local morphology, lithology, and the impact of tributaries. Mean standard deviation of laterals and verticals shows the strongest connection to SSC, rather than discharge and flow velocity. Comparing cross-sectional average SSC with surface-sampling from the middle of the river ranges from strong underestimations (> 70 %) to strong overestimations (> 100 %) for single years with an average underestimation of approx. 11 % for all three stations over the 30-year sampling period used in this study. Thereby, incorporating cross-sectional measurements reduce uncertainties induced by point-sampling. Further, site specific adaptations regarding the sample location and an optimization of the sampling process utilizing simultaneous sampling could improve cross-sectional sampling.

The successive breakdown of the lignin macromolecule into smaller units is the key to generate high value-added products from this complex plant polyphenol. Obtaining well-defined aromatic compounds is, therefore, an important step towards the production of biobased chemicals for the fuel, coating and lubricant industries. Nevertheless, processes requiring lignin dissolution are always challenging. Dissolving this macromolecule in an environment-friendly way takes this challenge to a whole new level. Levulinic acid, an organic compound formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, we describe a system consisting of levulinic acid as a biobased solvent for the reductive electrochemical depolymerization of lignin. Copper was used as an electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high-resolution mass spectrometry and NMR structural characterization revealed lignin-derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. The effect of the depolymerized lignin as an anti-corrosion coating was assessed, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass-based solvent, these results demonstrate a straightforward approach to produce high value-added compounds or tailored biobased materials.

Understanding of structural preferences and dynamics of water at the TiO2–H2O interface is fundamentally impor- tant in the perspective of broad range of TiO2 applications that extend from bio-adsorption for medical devices, photo- catalysis for energy production, to coatings with remarkable self-cleaning and anti-fogging properties. However, current knowledge on these systems under full hydration result almost entirely from modelling rather than direct experimental observations. Surface-sensitive techniques like electron microscopy (EM) or X-ray photoelectron spectroscopy (XPS) operate under high vacuum, therefore do not provide insights into phenomena underlying the real catalytic and bio-adsorption processes that take place under wet conditions. Herein, atomic-level characterization of TiO2 nanoparticles surface under full hydration was performed by a combination of 1H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics density functional theory (MD-DFT) simulations. Thanks to partial proton to deuteron exchange and fast MAS, resolved NMR signals from OH/H2O species at the TiO2–H2O interface could be observed and interpreted with chemical shifts calculations performed on system evolution trajectory frames. Presence of the recently debated atmospheric carboxylic acids was confirmed, however, the amount of these was small compared to OH/H2O surface species. Surface protonation and evolution of hydrogen-bonded network are shown to govern the surface chemistry of TiO2 under wet conditions.

Lignin is a renewable biopolymer, and its chemical functionalization renders it a prospective material for a plethora of applications. Within this respect, we present a method for lignin immobiliza...

Spherical mesoporous carbon (with a particle size in the range of 40–75 μm) was synthesized by nanoreplication of a hard silica template using sucrose as the carbon precursor. The mesoporous carbon...

Chitosan was deposited on fumed silica without the addition of cross-linkers or activating agents. The chitosan surface layer has a high affinity toward organic molecules, e.g., Acid Orange 8 (AO8) dye, robust to a broad range of simulated conditions (variance with respect to temperature, time, and concentration of solute). Experimental equilibrium data were analyzed by the generalized Langmuir equation taking into consideration the energetic heterogeneity of the adsorption system. The effect of temperature on dye uptake and adsorption rate was studied. According to the calculated thermodynamic functions ΔG°, ΔH°, and ΔS° from the equilibrium data at different temperatures, the adsorption of AO8 onto chitosan–fumed silica composite is exothermic and spontaneous. The studies of temperature effect on adsorption equilibrium show that the maximum adsorption capacity (determined from the Langmuir–Freundlich equation) of synthesized composite toward AO8 is about one-third higher in the case of an isotherm measured at 5 °C than this value obtained for the isotherm measured at 45 °C. The quantitative binding of dye molecules to chitosan coating on the surface of silica was proved by 1H MAS NMR. The deep kinetics study through the application of various theoretical models—the first-order equation, pseudo-first-order equation, second-order equation, pseudo-second-order equation, mixed first, second-order equation, and multiexponential equation—was applied for getting inside the mechanism of AO8 binding to the chitosan coating. Structural characteristics of chitosan-coated silica were obtained from the low-temperature adsorption/desorption isotherms of nitrogen and imaging by scanning electron microscopy. The effects of a synthetic route for polymer coating on thermal stability and the ability to degrade were studied by differential scanning calorimetry.

Anatase TiO2 nanoparticles with an average crystallite size of ~ 20 nm are synthesized through a sol-gel method. A composite anode for Li-ion batteries is prepared with the synthesized TiO2 nanoparticles and reduced graphite oxide (RGO) as the conductive carbon source. After the preparation of TiO2/RGO nanocomposite, a novel surface modification is carried out by the employment of H2O2 to enhance the overall electrochemical performance of nanocomposite anode (TiO2/RGO-P composite). The physical and chemical characterizations of the surface modified TiO2/RGO-P composites are performed with X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analyses. The electrochemical performance of TiO2/RGO-P composite electrodes is investigated via galvanostatic charge-discharge cycling tests in a potential window of 1.0–3.0 V. Compared to the plain TiO2/RGO composite anode, the TiO2/RGO-P composite anode has higher reversible capacities and better cycling performance due to the enhanced and stable formation of 3D channels of TiO2 nanoparticles with RGO stemming from the surface modification with H2O2. The TiO2/RGO-P composite anode delivers reversible discharge capacities around 291 mA h g−1 at a rate of 100 mA g−1, whereas the value stays at 214 and 143 mA h g−1 for the plain TiO2/RGO composite and TiO2 nanoparticle without any RGO, respectively.

The effect of bimetallic monodisperse CoPd nanoparticles on the microstructure and the shear strength of the Cu/ SAC305/Cu solder joint was investigated. The nanocomposite Sn–3.0Ag–0.5Cu (SAC305) solders with 0.1, 0.3, 0.5, and 1.0 wt% nanoCoPd were prepared through a paste mixing method. The employed bimetallic nanoparticles were produced via a modified oleylamine method. The microstructural analysis of as-solidified Cu/solder/Cu joints was performed by scanning electron microscopy. The results showed that initial additions of CoPd nanoparticles into the SAC305 solder promoted the growth of the interfacial planar-type Cu3Sn IMC layer; while the average thickness of the interfacial scallop-type Cu6Sn5 IMC layer slightly decreased. Further additions of the nanosized CoPd admixtures to the SAC305 solder paste lead to a significant increase of the average thickness of the Cu6Sn5 intermetallic compound layer up to 40%. The shear strength measurements were performed to investigate a relationship between the microstructure and mechanical properties of the investigated solder joints. The results indicated a decrease in the shear strength of the SAC305 solder joint by addition of 0.1 wt% CoPd NPs, while a difference in absolute values between solder joints with 0.3, 0.5, and 1.0 wt% nanoCoPd was practically insignificant.

Lead cyanamide PbNCN was synthesized by solid-state metathesis between PbCl2 and Na2NCN in a 1 : 1 molar ratio, and its structure was confirmed from Rietveld refinement of X-ray data. Electronic-structure calculations of HSE06 density-functional type reveal PbNCN to be an indirect semiconductor with a band gap of 2.4 eV, in remarkable quantitative agreement with the measured value. Mott-Schottky experiments demonstrate PbNCN to be a p-type semiconductor with a flat-band potential of 2.3 eV vs. the reversible hydrogen electrode (RHE) which is commonly used to estimate the value of the valence band edge position. Moreover, thin films of powderous PbNCN were assembled into a photoelectrode for photoelectrochemical water splitting. On the example of p-type PbNCN, this study provides the first experimental evidence that MNCN compounds can be applied as photocathodes for reductive reactions in photoelectrochemical cells.

Cobalt-based Li-ion batteries are produced globally on a massive scale, but most are discarded to landfill at the end of their useful lifetime. In this work, an efficient cobalt catalyst for the hydrolysis of sodium borohydride to dihydrogen was prepared from lithium ion battery waste, providing a second life for valuable minerals. This material is composed of a mixed metal cobalt–aluminium oxide supported on graphene, as elucidated by a combined FTIR, Raman, SEM, scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) and energy-dispersive X-ray spectroscopy (EDS) study. The obtained metal oxide material, which exhibits an average oxidation state for Co of 2.45, is a languid catalyst at room temperature, but rapid hydrogen production of up to 49 L(H2) min−1 g−1(Co) was observed in catalytic runs heated to 70 °C. This carbon-supported cobalt catalyst is competitive with designed cobalt nanostructured catalysts prepared from pure precursors. This work is illustrative of the opportunities which arise when e-waste is utilised as a mineral resource within the scope of a circular economy.

The development of smart and sustainable photocatalysts is in high priority for the synthesis of H

Quaternary tantalum-based oxynitrides ATa(O,N)3, with electronic band gaps between 1.8 and 2.4 eV, are promising materials for photochemical water-splitting. The tailoring of their surface properties is a critical aspect to obtain efficient hole extraction. We report on the origin of improved photoelectrochemical (PEC) water oxidation by means of acidic treatment for this class of compounds on the example of cubic CaTaO2N particles. We address the effect of acidic treatment by using complementary physical characterization techniques, such as X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), 1H and 14N solid-state nuclear magnetic resonance (NMR) spectroscopy, electron microscopy and electronic band structure calculations at the density functional theory (DFT) level. In combination with photoelectrochemical measurements, solid-state NMR indicates that the restructured surface displays a meaningfully higher concentration of terminating OH groups. Subsequent deposition of a nickel borate (NiBi) catalyst on the acid-treated surface yields a higher percentual upsurge of photocurrent in comparison to pristine CaTaO2N. Our results highlight the application of solid-state NMR spectroscopy for understanding of the semiconductor-catalyst interface in photochemical devices.

Quaternary metal oxynitride-based photoanodes with a large light transmittance are promising for high solar-to-hydrogen (STH) conversion efficiency in photoelectrochemical (PEC) tandem cells. Transparent substrates to support PEC water-splitting were fabricated using atomic layer deposition (ALD) to synthesize 30 and 60 nm GaN on SiC sub-strates. A generalized approach was used to grow a quaternary metal oxynitride, i.e. SrTaO2N thin film on the GaN/SiC substrates. The transparency above 60% in the wide solar spectrum highlights its availability of transmit-ting visible light to the rear side. A photocurrent onset at ca. −0.4 V vs. reversible hydrogen electrode (RHE) was achieved by the SrTaO2N/GaN/SiC photoanodes in a 0.1 M NaOH electrolyte under simulated solar irradiation. This paves the way for construction of hierarchically nanostructured tandem PEC cells. This work demonstrates the viabil-ity of integrating ALD in constructing substrates for semi-transparent quaternary metal oxynitride photoanodes.

Mossbauerite, a trivalent iron-only layered oxyhydroxide, has been recently identified as an electrocatalyst for water oxidation. We investigated the material as potential cocatalyst for photoelect...

Layered bismuth oxides exhibit a broad range of tunable physical properties as a result of their excellent structural versatility which facilitates compositional substitutions at both cationic and ...

Introduction: Coronavirus disease 19 (COVID-19) rapidly spread worldwide. The search for effective measures to counter the development and effects of the pandemic includes: identifying the disease pathogen, introducing methods of reducing its transmission, building the population immunity, and the search for a cure, both among the new and already-known substances with potential antivirus activity such as amantadine hydrochloride.Study objectives: The study's aim is an observational single-center analysis of confirmed COVID-19 cases treated with amantadine in ambulatory settings.Patients and methods: The group of 55 patients with confirmed COVID-19 diagnosis was treated in ambulatory settings by amantadine with a treatment schema. A retrospective analysis was based on symptoms, hospitalization, and number of deaths.Results: The mean age of the patients was 55.9 years (SD=15), and most patients were male (60%). Despite the majority of patients 64% (n=35) suffering from comorbidities and 53% (n=29) of patients having been diagnosed with pneumonia, none of them died, and only four had required hospitalization in the course of COVID-19. Clinical stabilization was achieved in 91% (n=50) of patients within 48 hours after the first dose of amantadine with further improvement; additionally, all patients experienced remission of COVID-19. In total, 93% (n=51) of patients did not require hospitalization during the treatment.Conclusions: The data may suggest that amantadine hydrochloride shows efficacy in preventing hospitalization and deaths in patients with COVID-19. At the same time, it emphasizes that daily monitoring of the patient and regular examination are important in the case of SARS-CoV-2 infection dynamics.

Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state 15N NMR (ssNMR) spectroscopy is a powerful tool for the determination of such positions in N-doped carbon at natural 15N isotope abundance. Here we report a green chemistry approach for the synthesis of N-doped carbon using cellulose as a precursor, and a study of the catalytic properties and atomic structures of the related catalyst. N-doped carbon (NH3) was obtained by the oxidation of cellulose with HNO3 followed by ammonolysis at 800 °C. It had a N content of 6.5 wt% and a surface area of 557 m2 g-1, and 15N ssNMR spectroscopy provided evidence for graphitic nitrogen besides regular pyrrolic and pyridinic nitrogen. This structural determination allowed probing the role of graphitic nitrogen in electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitrite reduction reaction. The N-doped carbon catalyst (NH3) showed higher electrocatalytic activities in the OER and HER under alkaline conditions and higher activity for nitrite reduction, as compared with a catalyst prepared by the carbonization of HNO3-treated cellulose in N2. The electrocatalytic selectivity for nitrite reduction of the N-doped carbon catalyst (NH3) was directly related to the graphitic nitrogen functions. Complementary structural analyses by means of 13C and 1H ssNMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature N2 adsorption were performed and provided support to the findings. The results show that directly-excited 15N ssNMR spectroscopy at natural 15N abundance is generally capable of providing information on N-doped carbon materials if relaxation properties are favorable. It is expected that this approach can be applied to a wide range of solids with an intermediate concentration of N atoms.

The growing demand for Li-ions batteries (LIBs) has made their postconsumer recycling an imperative need towards the recovery of valuable metals, such as cobalt and nickel. Nevertheless, their recovery and separation from active cathode materials in LIBs, via an efficient and environmentally friendly process, have remained a challenge. In this work, we approach a simple and green method for the selective separation of nickel ions from mixed cobalt-nickel aqueous solutions under mild conditions. We discovered that the bioinspired microporous metal–organic framework (MOF), Bi2O(H2O)2(C14H2O8)∙nH2O is a selective sorbent towards Ni(II) ions at pH 5-7, but does not adsorb Co(II) ions. According to the Freundlich isotherm, the adsorption capacity towards Ni(II) reached 100.9 mg∙g−1, while a near-zero adsorption capacity was found for Co(II) ions. Ni(II) removal from aqueous solutions was performed at mild conditions (22 °C and pH 5), with a high yield up to 96%. Presence on Ni(II) ions adsorbed on the surface of the material has been proven by solid state 1H nuclear magnetic resonance (NMR) spectroscopy. Finally, separation of Ni(II) from Co(II) from binary solutions was obtained with approximately 30% yield for Ni(II), with a near-zero adsorption of Co(II), which has been demonstrated by UV-Vis spectroscopy. These results offer a green pathway toward the recycling and separation of valuable metals from cobalt-containing LIBs, while providing a sustainable route for waste valorization in a circular economy.

Suspended sediment contributes to the vast majority of the annual sediment load transported by rivers to the global oceans. At the same time, this large fraction is transported just in a fraction of time. Towards achieving sustainable sediment management and healthy fluvial systems, identifying the impact of the temporal variability on annual load estimates becomes indispensable in order to reduce uncertainties.We aim to estimate the temporal variability of suspended sediment transport and the uncertainty of annual suspended sediment loads. Our approach is based on high-resolution time series (15 min sampling interval) of discharge and suspended sediment concentration (SSC) at four monitoring stations with different degrees of discharge variability. The quantification of the variability of discharge and sediment yield is achieved through the exceedance time. The uncertainty of the annual sediment load is estimated using a bootstrap approach. We assess the impact of the sampling interval and link the optimal sampling interval to different SSC-variability. Further, the impact of rating parameters on the uncertainty of annual loads is investigated.Our results indicate an increase in SSC-variability with decreasing discharge, leading to a negative relationship with the contributing catchment area. The 80 % exceedance times for the annual sediment load range from less than 10 % for the river Ammer (catchment area 608 km²) between 10 – 20 % for the rivers Ilz (765 km²) and Moselle (27 088 km²) to more than 40 % for the river Rhine (109 806 km²). Simultaneously, the variability increases with a decrease in sampling frequency. Our preliminary results indicate a negative exponential relationship between exceedance time and uncertainties in annual load estimates. This relationship can be used to estimate the uncertainty of annual loads estimated based on low frequency sediment sampling at the continental to global scale.