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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.

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.

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...

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.

The simultaneous removal of organic and inorganic pollutants from wastewater is a complex challenge and requires usually several sequential processes. Here, we demonstrate the fabrication of a hybrid material that can fulfill both tasks: (i) the adsorption of metal ions due to the negative surface charge, and (ii) photocatalytic decomposition of organic compounds. The bioinorganic hybrid membrane consists of cellulose fibers to ensure mechanical stability and of Bi4O5Br2/BiOBr nanosheets. The composite is synthesized at low temperature of 115 °C directly on the cellulose membrane (CM) in order to maintain the carboxylic and hydroxyl groups on the surface that are responsible for the adsorption of metal ions. The composite can adsorb both Co(II) and Ni(II) ions and the kinetic study confirmed a good agreement of experimental data with the pseudo-second-order equation kinetic model. CM/Bi4O5Br2/BiOBr showed higher affinity to Co(II) ions than to Ni(II) ions from diluted aqueous solutions. The bioinorganic composite demonstrates a synergistic effect in the photocatalytic degradation of rhodamine B (RhB) by exceeding the removal efficiency of single components. The fabrication of the biologic-inorganic interface was confirmed by various analytical techniques including scanning electron microscopy (SEM), scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM EDX) mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The presented approach for controlled formation of the bioinorganic interface between natural material (cellulose) and nanoscopic inorganic materials of tailored morphology (Bi–O–Br system) enables the significant enhancement of materials functionality.

Lubricant degradation by additive depletion, contamination and build-up of degradation products deteriorates lubrication performance. It can be expected that engine oil degradation also has an impact on performance parameters. Engine development tends to higher power density, lower engine oil viscosity to optimize fuel efficiency, which heavily stress engine oils and thus demand increased oil performance. Correlations between engine oil degradation, friction and wear during an engine oil’s lifetime are a valuable asset in engine development towards performance, longevity and cost reduction. Here, physical-chemical and tribological properties of engine oils collected from passenger cars were determined. The results revealed the deterioration of friction (loss of fuel efficiency) and wear (increasing loss of material) depending on mileage. Defined used engine oils were produced by artificial alteration in a large-scale device and showed a very good correlation with the field samples.

Purpose This paper aims to compare the conditions of in-service oils from diesel and gasoline engines, with focus on nitration. Design/methodology/approach Oil conditions of seven engine oil samples from five diesel-fueled vehicles and nine oil samples from eight gasoline-fueled vehicles with total mileage ranging from 13,600 to 30,000 km were determined via Fourier-transform infrared spectroscopy as well as neutralization number (NN) and total base number titration. Findings Chemical deterioration was characterized by significant differences in oxidation, nitration, NN increase and residual aminic antioxidant contents. Social implications Submitted in connection with the Special Issue, “Young Tribologists – Insights into the work of the new generation”. Originality/value Uncovering differences in the oil degradation of oils from gasoline and diesel engines enables improved condition-based maintenance strategies and the prediction of oil condition dependent tribological performance.

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.

Catalysis science & technology (2022). doi:10.1039/d2cy00050d, Published by RSC Publ., London

Lubrication of an internal combustion engine is critical for unwanted energy and material losses. Zinc dialkyldithiophosphate (ZDDP) is a commonly used anti-wear additive that forms by in situ decomposition a protecting interface between sliding surfaces. The interface consists of the tribofilm on both surfaces and oil in the contact. Soot particles from a petrol engine and gas engine were analyzed using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques: electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDS). These techniques revealed that the end-products in soot contain 3-5 nm ZnO-based particles with additions of phosphorus and sulfur, originating from the ZDDP anti-wear additive. Our results unravel the tribofilm decomposition under real field conditions and hint toward potentially unidentified hazards with respect to ZDDP-containing lubricants.

CuWO4 is a photoanode candidate in neutral pH, and manganese-based oxygen evolution reaction electrocatalysts are of high interest due to their low price and low toxicity. Considering the unexplored chemistry of transition-metal carbodiimides/cyanamides for the PEC water oxidation, we investigated MnNCN as an electrocatalyst for CuWO4 under AM 1.5G illumination in potassium phosphate electrolyte (pH 7). Surface functionalization of CuWO4 photoanodes with MnNCN increased the photocurrent from 22 to 30 μA cm-2 at 1.23 V vs RHE. Complementary structural analysis by means of XRD and XPS revealed that MnNCN forms a core-shell structure MnNCN@MnPO x in phosphate electrolyte and mimics a manganese phosphate electrocatalyst. As such, the surface chemistry of MnNCN significantly differs from previous studies on the cobalt analogue (CoNCN). A separately prepared MnNCN electrode developed a small but detectable photocurrent due to photogenerated holes inside the semiconducting carbodiimide core of the MnNCN@MnPO x structure.

With nanostructured materials such as catalytic heterostructures projected to play a critical role in applications ranging from water splitting to energy harvesting, tailoring their properties to specific tasks requires an increasingly comprehensive characterization of their local chemical and electronic landscape. Although aberration-corrected electron spectroscopy currently provides sufficient spatial resolution to study this space, an approach to concurrently dissect both the electronic structure and full composition of buried metal/oxide interfaces remains a considerable challenge. In this manuscript, we outline a statistical methodology to jointly analyze simultaneously-acquired STEM EELS and EDX datasets by fusing them along their shared spatial factors. We show how this procedure can be used to derive a rich descriptive model for estimating both transition metal valency and full chemical composition from encapsulated morphologies such as core-shell nanoparticles. We demonstrate this on a heterogeneous Co-P thin film catalyst, concluding that this system is best described as a multi-shell phosphide structure with a P-doped metallic Co core.

CuWO

Zintl phases: The new lithium-rich Zintl phase Li12Ag1−xSi4 (x=0.15) contains the highly charged 16-electron anion [AgSi2]7−. Chemical bonding is discussed based on electronic band structure analysis (see figure).

Alkaline earth monosilicides (AESi, AE = Ca, Sr, Ba) are poor metals, and their transport properties are not solely determined by the Zintl anion, in contrast to their Zintl-type composition. Their conducting network is formed by the depopulated ∞1[Si2−] π system and AE-d states. This justifies the special local coordination of the metal atoms and the planarity of the silicon chains. The low density of carriers seems to be a playground for magnetic instabilities and the triangular prismatic arrangement of AE atoms responsible for the observed weak glassy behavior.

A new phase, Sn(x)Pt4Sb(12-y)Sn(y), has been prepared from the elements. It exhibits a wide range of homogeneity with 0.3(2) < or = x < or = 1.0(2) and 4.2(2) < or = y < or = 7.0(2). The crystal structure and the composition were established by single-crystal and powder X-ray diffraction as well as wavelength-dispersive X-ray analysis measurements and were supported by nuclear magnetic resonance experiments. The compound is the first representative of the filled-skutterudite family with the filler atoms not located at the center of the cavity but covalently bonded to the cavity's wall, as confirmed by the analysis of chemical bonding with the electron localizability indicator. The Sn and Sb atoms share the framework site with different coordinate parameters caused by the difference in atomic size; additional tin atoms are located in the cavities of the framework. The material is a diamagnet in the whole composition range. In agreement with the calculated electronic density of states, the material reveals a metallic behavior in electronic transport. The absolute values of electrical resistivity vary with the tin-to-antimony ratio.

In our search for clathrates containing rare-earth elements we have discovered the three new clathrate-I phases K 6 Eu 2 Ga 10 Ge 36 , K 6 Eu 2 Zn 5 Ge 41 , and K 6 Eu 2 Cd 5 Ge 41 . The Eu atoms occupy only the smaller cages (pentagondodecahedra) leading to a fully ordered arrangement of the guest atoms. X-ray absorption spectroscopy and magnetic susceptibility measurements reveal that at room temperature and above Eu is close to divalent in all compounds. Magnetization measurements at low temperatures, however, may indicate slightly reduced magnetic moments for K 6 Eu 2 Ga 10 Ge 36 and K 6 Eu 2 Zn 5 Ge 41 . The ferromagnetic ordering temperatures of 3.8, 4.0, and 9.3 K for K 6 Eu 2 Ga 10 Ge 36 , K 6 Eu 2 Zn 5 Ge 41 , and K 6 Eu 2 Cd 5 Ge 41 , respectively, are considerably reduced with respect to the 36 K observed for the type-I clathrate β - Eu 8 Ga 16 Ge 30 where all cages are occupied by Eu.

The new compound Yb2+3—xPd12—3+xP7x = 0.40(4)) was synthesized by sintering of a mixture of elemental components at 1100 °C with subsequent annealing at 800 °C. The crystal structure of Yb2+3—xPd12—3+xP7 was solved and refined from X-ray single-crystal diffraction data: space group P6¯, a = 10.0094(4)A, c = 3.9543(2)A, Z = 1; R(F) = 0.022 for 814 observed unique reflections and 38 refined parameters. The atomic arrangement reproduces a structure motif of the hexagonal Zr2Fe12P7 type in which one of the transition metal positions is substituted predominantly by ytterbium (Yb : Pd = 0.86(1) : 0.14). The ytterbium atoms are embedded in the 3D polyanion formed by palladium and phosphorus atoms. Two different environments for ytterbium atoms are present in the structure. Magnetic susceptibility measurements and XAS spectroscopy at the Yb LIII edge show the presence of ytterbium in two electronic configurations, 4ƒ13 and 4ƒ14. The following model was derived. Ytterbium atoms in the 3k site are in the 4ƒ13 state, the two remaining positions contain ytterbium in intermediate-valence states, giving totally 79 % ytterbium in the 4ƒ13 electronic configuration. Yb2+3—xPd12—3+xP7 (x = 0.40): verschiedene Ytterbium-Spezies in einem Substitutionsmotiv des Zr2Fe12P7-Strukturtyps Eine neue Verbindung Yb2+3—xPd12—3+xP7 (x = 0.40(4)) wurde durch Sintern der Elementmischung bei 1100 °C mit anschliesendem Tempern bei 800 °C dargestellt. Die Kristallstruktur von Yb2+3—xPd12—3+xP7 wurde aus Einkristall-Daten ermittelt und verfeinert: Raumgruppe P6¯, a = 10.0094(4)A, c = 3.9543(2)A, Z = 1; R(F) = 0.022 fur 814 Reflexe und 38 Variablen. Die Atomanordnung in der Struktur von Yb2+3—xPd12—3+xP7 gibt das Motiv des hexagonalen Zr2Fe12P7-Typs wieder, wobei jedoch eine der Ubergangs-Metall-Positionen uberwiegend mit Ytterbium besetzt wird (Yb : Pd = 0.86(1) : 0.14). Die Ytterbium-Atome sind in einem dreidimensionalen Polyanion aus Palladium- und Phosphor-Atomen eingebettet. Das Existenz von zwei verschiedenen Umgebungen fur Ytterbium in der Struktur wurde durch Messungen der magnetischen Suszeptibilitat und durch XAS-Spektroskopie bestatigt. Beide zeigen Ytterbium in zwei elektronischen Konfigurationen, 4ƒ13 und 4ƒ14. Die Ergebnisse lassen sich mit einem Model beschreiben, in dem die Ytterbium-Atome zum einen die 4ƒ13-Konfiguration (Wyckoff-Lage 3k) und zum anderen eine zwischenvalente Konfiguration aufweisen. Daraus resultiert eine 4ƒ13-Konfiguration fur insgesamt 79 % des Ytterbiums.

Jede Menge Lithium: Die Silicide Li7CuSi2, mit dem linearen Zintl-Anion [Si-Cu-Si]7− (siehe Bild), und Li7.3CuSi3 sind die Verbindungen mit dem hochsten Lithiumgehalt in diesem ternren System. Die Kristallstrukturen und Bindungsverhltnisse beider Verbindungen werden besprochen.

The title compound was prepared from elements by sintering in the temperature region between 1073 and 1473 K. The monoclinic structure of La7Pd17P12 was solved and refined from X-ray single crystal data: space group C2/m, a = 24.519(1), b = 4.0859(5), c = 13.6106(8)Å , β = 112.129(3)°, Z = 2, RF = 0.025 for 1065 unique of 4877 measured reflections and 112 refined parameters. Main structural motif of the new phosphide are condensed blocks of trigonal prisms around phosphorus atoms connected to infinite chains via lanthanum atoms. The structural features of La7Pd17P12 are discussed in comparison with some representatives of a large family of structures with metal / non-metal ratio close to 2 : 1.

Materials with a low degree of space filling may have low thermal conductivity. If combined with the enhanced thermopower, often observed in strongly correlated rare-earth or transition metal containing materials, this may result in a material with superior thermoelectric properties for cooling applications. YbGa6Te10 is a new rare-earth containing material. The thermal conductivity of this compound is very low and is explained in terms of low degree of space filling, large unit cell and relatively heavy elements. The very low thermal conductivity makes this compound or similar modifications a potential candidate for a strongly correlated thermoelectric material.

The new compounds Li7CuSi2 (I) and Li7.3CuSi3 (II) are synthesized from the elements (Nb ampule, 600 °C, 7 d) and characterized by XRD, magnetic measurements, and band structure calculations.

A new phase, Sn(x)Pt4Sb(12-y)Sn(y), has been prepared from the elements. It exhibits a wide range of homogeneity with 0.3(2) < or = x < or = 1.0(2) and 4.2(2) < or = y < or = 7.0(2). The crystal structure and the composition were established by single-crystal and powder X-ray diffraction as well as wavelength-dispersive X-ray analysis measurements and were supported by nuclear magnetic resonance experiments. The compound is the first representative of the filled-skutterudite family with the filler atoms not located at the center of the cavity but covalently bonded to the cavity's wall, as confirmed by the analysis of chemical bonding with the electron localizability indicator. The Sn and Sb atoms share the framework site with different coordinate parameters caused by the difference in atomic size; additional tin atoms are located in the cavities of the framework. The material is a diamagnet in the whole composition range. In agreement with the calculated electronic density of states, the material reveals a metallic behavior in electronic transport. The absolute values of electrical resistivity vary with the tin-to-antimony ratio.

CaH8Mn2O12, orthorhombic, Pccn (no. 56), a = 13.9791(19) A, b = 5.5404(8) A, c = 13.3908(18) A, V = 1037.1(2) A, Z = 4, Rgt(F) = 0.0318, wRref(F ) = 0.0659, T = 293 K.

The title compound was prepared from elements by sintering in the temperature region between 1073 and 1473 K. The monoclinic structure of La 7 Pd 1 7 P 1 2 was solved and refined from X-ray single crystal data: space group C2/m, a = 24.519(1), b = 4.0859(5), c = 13.6106(8) A,β = 112.129(3)°, Z = 2, R F = 0.025 for 1065 unique of 4877 measured reflections and 112 refined parameters. Main structural motif of the new phosphide are condensed blocks of trigonal prisms around phosphorus atoms connected to infinite chains via lanthanum atoms. The structural features of La 7 Pd 1 7 P 1 2 are discussed in comparison with some representatives of a large family of structures with metal / non-metal ratio close to 2: 1.