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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.

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.

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.