Hetero Elements Research Articles

Lotus pollen-derived nitrogen and phosphorus self-doped TiO2/carbon materials for photoelectrochemical application

The wide band gap and low conductivity of TiO2 limit its application for photocatalytic H2 production. In this work, a nitrogen (N) and phosphorus (P) self-doped TiO2/Carbon (TiO2/C) composite with an egg yolk-shell structure was successfully synthesized using a lotus pollen template synthesis approach. The microstructure and photoelectrochemical performance of the composite materials were investigated. The introduction of hetero elements decreased the band gap of the TiO2/C composite, extending light absorption to the visible light region. Additionally, the enhanced conductivity facilitated fast charge transfer and prolonged the lifespan of electron/hole pairs. Consequently, the N, P self-doped TiO2/C composite exhibited higher H2 production (656.18 μmol·g−1·h−1) than commercial TiO2 (418.12 μmol·g−1·h−1) under simulated sunlight irradiation.

Simultaneous enhancement of the optical absorption, ferroelectric polarization, and photocatalytic activity by designing the Ti/Fe ratio for Bi5Ti3FeO15

Bismuth-contained Aurivillius compounds are potentially low-cost and eco-friendly photocatalysts for organic pollutant degradation because of their unique layered crystal structure. Bi5Ti3-xFe1+xO15 (BTF-x, x = 0–1) photocatalysts were synthesized through the molten salt method. The crystal structure was determined by XRD Rietveld refinements. The phase constitution was found to change from a single 4-layered Aurivillius phase for x = 0 to mixed Aurivillius phases with different layer numbers as x increases. BTF-0.8 and BTF-1 exhibit better frequency stability of dielectric properties. The decrease in the Ti/Fe ratio leads to a monotonic reduction of the bandgap, ascribed to the increase in the octahedral distortion rather than the oxygen vacancy concentration. Surprisingly, the ferroelectric polarization is also improved by decreasing the Ti/Fe ratio and the best ferroelectricity was obtained in BTF-1. The photocatalytic activity of BTF-x catalysts was examined by RhB degradation under visible-light irradiation. The decrease in the Ti/Fe ratio also enhances the photocatalytic activity of BTF-x catalysts. The fastest photodegradation rate was obtained in BTF-1, about 9 times higher than that of BTF-0. Scavenger test studies confirmed that the level of contribution to RhB photodegradation was h+, O2•−, and •OH radicals in descending order. Furthermore, the excellent stability and reusability of BTF-x catalysts were demonstrated by the photocatalytic cycle tests. All the results suggested without introducing hetero elements, adjusting the Ti/Fe ratio was an effective means to narrow the bandgap, improve the ferroelectricity and enhance the photocatalytic activity simultaneously. We hope the present study can be generalized to other Aurivillius phases to acquire much better performance and broader application.

Recent Progress in Developing Thioether-Containing Ligands for Catalysis Applications

AbstractThe ligand that stabilizes the metal center is crucial to its catalytic activity. Historically dominated by phosphorus and nitrogen, sulfur has long been little considered as a hetero element for stabilizing a potentially active metal center. However, this situation is changing and we are seeing more and more examples that incorporate this element. This review provides an overview of recent transition-metal-catalyzed reactions with ligands containing neutral sulfur groups, i.e. thioethers. A selection of examples published since 2013 illustrates the diversity of applications of thioether-containing ligands and shows that sulfur should be more widely used in the development of homogeneous catalysis.1 Introduction2 Phosphorus-Thioether Ligands3 Nitrogen-Thioether Ligands4 Oxygen-Thioether Ligands5 NHC-Thioether Ligands6 Cycloolefin-Thioether Ligands7 Conclusion

Effect of unpaired electron number elements (Al, Cr, Mn) doping in Fe2O3 on ortho to para hydrogen conversion at 77 K

Para hydrogen (p-H2), as a low-energy spin isomer of hydrogen molecule, has an important significance in the storage and transportation of liquid hydrogen. The ortho hydrogen (o-H2) to p-H2 conversion catalyst accelerates the intrinsically slow o-H2 to p-H2 conversion and becomes an essential component of the hydrogen liquefaction process. In this paper, doped Fe2O3 with different hetero elements (X-FO, X = Al, Cr, Mn) are prepared by a simple co-precipitation method to explore the effect of different unpaired electron numbers in doping elements on catalytic performance. It is shown that the disorder in the internal crystal structure of X-FO caused by doping of hetero elements is the main reason for the increased performance of X-FO, as this leads directly to an increase in the internal magnetic disorder. The catalytic performance is enhanced with the increase in the number of unpaired electrons in doping elements. Mn-FO with high unpaired electron number exhibits optimal catalytic performance. When the hydrogen flow rate is 100 mL min−1, p-H2 content is 49.45 % after catalytic conversion at 77 K. In this paper, a simple method is adopted, which has advantages in terms of production process and cost, and provides experimental support for the large-scale production of catalysts.

Molecular simulation on carbon dioxide capture performance for carbons doped with various elements

Among the different types of CO2 capture technologies for post-combustion, sorption CO2 capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption performance by doping hetero elements due to the rapid reaction kinetics and low costs. Herein, sorption capacity and selectivity for CO2 and N2 on carbon-based sorbents doped with elements such as nitrogen, sulfur, phosphorus, and boron, are evaluated and compared using the grand canonical Monte Carlo (GCMC) method, the universal force field (UFF), and transferable potentials for phase equilibria (TraPPE). The sorption capacities of N-doped porous carbons (PCs) at 50 °C were 76.1%, 70.7%, 50.6%, and 35.7% higher than those of pure PCs, S-doped PCs, P-doped PCs, and B-doped PCs, respectively. Its sorption selectivity at 50 °C was approximately 14.0, nearly twice that of pure PCs or other hetero-element-doped PCs. The N-doped PCs showed the largest sorption heat at 50 °C among all the PCs, approximately 20.6 kJ·mol−1, which was 9.7%−25.5% higher than that of the pure PCs under post-combustion conditions. Additionally, with the product purity of 41.7 vol.%−75.9 vol.% for vacuum pressure swing sorption, and 53.4 vol.%−83.6 vol.% for temperature swing sorption, the latter is more suitable for post-combustion conditions than pressure-swing sorption.

Lanthanides Singing the Blues: Their Fascinating Role in the Assembly of Gigantic Molybdenum Blue Wheels.

Molybdenum blues (MBs) are a distinct class of polyoxometalates, exhibiting versatile/impressive architectures and high structural flexibility. In acidified and reduced aqueous environments, isopolymolybdates generate precisely organizable building blocks, which enable unique nanoscopic molecular systems (MBs) to be constructed and further fine-tuned by hetero elements such as lanthanide (Ln) ions. This Review discusses wheel-shaped MB-based structure types with strong emphasis on the ∼30 Ln-containing MBs as of August 2021, which include both organically hybridized and nonhybridized structures synthesized to date. The spotlight is thereby put on the lanthanide ions and ligand types, which are crucial for the resulting Ln-patterns and alterations in the gigantic structures. Several critical steps and reaction conditions in their synthesis are highlighted, as well as appropriate methods to investigate them both in solid state and in solution. The final section addresses the homogeneous/heterogeneous catalytic, molecular recognition and separation properties of wheel-shaped Ln-MBs, emphasizing their inimitable behavior and encouraging their application in these areas.

Decision-making system with homo and hetero elements

Experts from all over the world provide an opportunity in filling decision-making systems. But the filling of decision-making systems with data does not have an exact quantitative characteristic. It is good when the expert is completely confident in the decision. But some decisions can add up to their own internal assessment without justification or experimentation. Other decisions are hampered by past experience. To overcome this type of problem, it is necessary to develop a system that will be based on clear and fuzzy data behaviour. This article is aimed at describing the method for constructing a decision-making system on clear and fuzzy data using Petri nets.

Preparation of Porous Carbon Material Derived from Cellulose with Added Melamine Sulfate and Electrochemical Performance as EDLC Electrode

Activated carbon derived from cellulose with added melamine sulfate, which is known as one of the chemicals having a flame-retardant effect on the cellulose, was produced in order to dope dual hetero elements, such as nitrogen and sulfur, and was used to improve the yields of the carbonization process and carbon dioxide (CO2) activation process. The addition of melamine sulfate resulted in suppression of the BET specific surface area. The Brunauer–Emmett–Teller (BET) specific surface area for the CO2-activated sample with 30 wt.%-added melamine sulfate was 578 m2 g−1. The existence of nitrogen atoms was confirmed in the CO2-activated sample with the added melamine sulfate. However, no peak assigned to the sulfur atom appeared in the x-ray photoelectron spectroscopy spectrum for the sample with the 30 wt.%-added melamine sulfate. In spite of the lower specific surface area of the samples containing the added melamine sulfate, the capacitance values of the carbon material derived from the cellulose with added melamine sulfate were higher than those of the carbon material derived only from cellulose.

Fate of Nitrogen and Sulfur during Reduction Process of Carbon-containing Pellet Prepared by Vapor Deposition of Gaseous-Tar and the Influences of the Hetero Elements on the Reduction Behavior and Crushing Strength

Fate of Nitrogen and Sulfur during Reduction Process of Carbon-containing Pellet Prepared by Vapor Deposition of Gaseous-Tar and the Influences of the Hetero Elements on the Reduction Behavior and Crushing Strength

Strain and Ligand Effects on CO2Reduction Reactions over Cu–Metal Heterostructure Catalysts

The strain and ligand effects on the adsorption energies of key intermediates (*COOH, *CO, *CHO, and *COH) in CO2 reduction reactions on the Cu–M(111) (M = Ni, Co, Cu, Rh, Ir, Pd, Pt) heterolayered catalysts have been quantitatively separated using first-principles calculations. Contrary to the common belief that strain is always the leading factor influencing catalytic performance of the core–shell type heterostructure catalysts, the ligand effect due to the underlying hetero elements should not be ignored and may become dominant for strain-insensitive adsorbates (*CO and *COH). Moreover, the models of Cu(2 ML/3 ML)–M(111) (M = Ir, Rh, Pt, Pd) have been shown to be better catalysts for CO2 reduction, as they require lower overpotential to drive the reaction than the Cu(111) slab. Particularly, the overpotential is predicted to be lowered by 0.17 V for Cu(3 ML)–Ir(111) model catalyst. Thus, both effects should be considered in heterostructure catalyst design.

Recycling oil-extracted microalgal biomass residues into nano/micro hierarchical Sn/C composite anode materials for lithium-ion batteries

We introduce a novel approach for the high-value production of nano/micro hierarchical structured Sn anodes for lithium-ion batteries (LIBs) by utilizing microalgal biomass residues that collaterally form during oil extraction for biofuel production. The Sn/C composites made from the oil-extracted microalgal biomass residues (the extracted Sn/C) exhibit the following advantages as high-energy-density anodes: 1) a homogeneous distribution of Sn nanoparticles in the carbon matrix (Sn/C), which efficiently relieves the strain caused by volume changes of the active materials; 2) a high porosity of Sn/C composites; and 3) a homogeneous distribution of the hetero elements N and P in the carbon matrix. Overall, the extracted Sn/C exhibit improved electrochemical performance in LIBs compared with the Sn/C composites made from the microalgal biomass residues without oil extraction (non-extracted Sn/C). The extracted Sn/C have improved rate capabilities (160.0 and 72.9mAhg−1 for the extracted Sn/C and the non-extracted Sn/C, respectively, at the 80th cycle, 3.5Ag−1) and improved cycle performances (511.7 and 493.2mAhg−1 for the extracted Sn/C and the non-extracted Sn/C, respectively, at the 300th cycle, 200mAg−1).

Investigation of Elemental Mass Spectrometry in Pharmacology for Peptide Quantitation at Femtomolar Levels.

In the search of new robust and environmental-friendly analytical methods able to answer quantitative issues in pharmacology, we explore liquid chromatography (LC) associated with elemental mass spectrometry (ICP-MS) to monitor peptides in such complex biological matrices. The novelty is to use mass spectrometry to replace radiolabelling and radioactivity measurements, which represent up-to now the gold standard to measure organic compound concentrations in life science. As a proof of concept, we choose the vasopressin (AVP)/V1A receptor system for model pharmacological assays. The capacity of ICP-MS to provide highly sensitive quantitation of metallic and hetero elements, whatever the sample medium, prompted us to investigate this technique in combination with appropriate labelling of the peptide of interest. Selenium, that is scarcely present in biological media, was selected as a good compromise between ICP-MS response, covalent tagging ability using conventional sulfur chemistry and peptide detection specificity. Applying selenium monitoring by elemental mass spectrometry in pharmacology is challenging due to the very high salt content and organic material complexity of the samples that produces polyatomic aggregates and thus potentially mass interferences with selenium detection. Hyphenation with a chromatographic separation was found compulsory. Noteworthy, we aimed to develop a straightforward quantitative protocol that can be performed in any laboratory equipped with a standard macrobore LC-ICP-MS system, in order to avoid time-consuming sample treatment or special implementation of instrumental set-up, while allowing efficient suppression of all mass interferences to reach the targeted sensitivity. Significantly, a quantification limit of 57 ng Se L-1 (72 femtomoles of injected Se) was achieved, the samples issued from the pharmacological assays being directly introduced into the LC-ICP-MS system. The established method was successfully validated and applied to the measurement of the vasopressin ligand affinity for its V1A receptor through the determination of the dissociation constant (Kd) which was compared to the one recorded with conventional radioactivity assays.

Large-Scale Synthesis of Metal-Ion-Doped Manganese Dioxide for Enhanced Electrochemical Performance.

One-dimensional (1D) MnO2 was widely applied in areas of enzyme biosensors, industrial sieves, and energy storage materials owing to its excellent thermal, optical, magnetic, and chemical features. However, its practical application into energy storage devices is often hindered by the bad electronic conductivity (from 10(-5) to 10(-6) S cm(-1)). As is widely known, doping with hetero elements is an efficient way to enhance the electronic conductivity of metal oxides. Herein, a novel and simple molten-salt method is developed to achieve a large-scale preparation of 1D MnO2 nanowires. Such an approach also realizes the easy tuning of electrical properties through doping with different transition metal ions. On the basis of first-principle calculation as well as four-probe measurement, we determined that the conductivity of the doped MnO2 nanowires can be promoted efficiently by utilizing such protocol. Meanwhile, a possible doping route is discussed in detail. As a result, a superior electrochemical performance can be observed in such metal ions (M(+))-doped nanowires. Such high-quality M(+)-doped MnO2 nanowires can satisfy a broad range of application needs beyond the electrochemical capacitors.

Homensexual e heteridade

Based on Lacan, this article seeks to demonstrate that homosexuality does not exist, as for sex to take place, both sexes are needed. Taking the texts “L’.tourdit” and in the “Seminar Encore”, both by Lacan, from the early 1970s, it is demonstrated through the formulae of sexuation that it does not matter on which side in division of the of the sexes one is, the sexuality of the parletre is always of the order of Heteros, beyond the anatomical difference of the sexes. In order for sexuality between man and woman, two men, or two women to exist, the presence of the hetero element is crucial, which is the relation between a fully phallic element and a non-fully phallic one.

Synthesis and Structure of Hexatungstochromate(III), [H3Cr(III)W6O24]6-.

The hexatungstochromate(III) [H(3)Cr(III)W(6)O(24)](6-) (1) was synthesized in aqueous, basic medium by simple reaction of chromium(III) nitrate nonahydrate and sodium tungstate dihydrate in a 1:6 ratio. Polyanion 1 represents the first Anderson-Evans type heteropolytungstate with a trivalent hetero element. The sodium salt of 1 with the formula Na(6)[H(3)Cr(III)W(6)O(24)]·22H(2)O (1a) was fully characterized in the solid state by single crystal XRD, FT-IR spectroscopy, and thermogravimetric analysis.

Silicon Oxycarbide Ceramics As Anode Materials for Li-Ion Batteries: Modification of the Structure and Composition to Enhance the Li Storage Properties

Li-ion battery technology is one of the promising energy storage solution for the future. Studies based on electrode materials are one of the key step to improve the energy storage performance of these systems. Recent studies shows that polymer derived silicon oxycarbide (SiOC) ceramics can be considered as a potential anode material. SiOC ceramics are generally amorphous in nature and usually consists of a network of disordered free carbon segregated in amorphous SiOC matrix. The complex nanostructure plays a crucial role in determining their functional properties. Carbon rich SiOCs (>20wt% free carbon) is found to be the best candidate for Li storage. The enhanced Li ion storage capacity of SiOC ceramics is generally explained in connection with the disordered free carbon phase which stores lithium in interlayer spaces along with at the edges of the carbon clusters and mixed SiOC phase stoichiometry supporting the stability of the system. The main disadvantage of this material is the first cycle irreversible capacity loss which arises mainly due to the presence of oxygen, defects, micro pores etc. By synthesizing SiOC compositions with different stoichiometry it has been shown that carbon-rich SiOC ceramics with ~50wt% of free carbon and remaining amorphous SiOC matrix is the best candidate for reversible lithium storage demonstrating higher reversible capacity of 600 mAh g-1with a good cycling stability. Within our work SiOC ceramics have been synthesized from polysiloxanes using different cross-linking and heat treatment approach. In a typical preparation a linear polysiloxane is cross-linked with divinylbenzene (DVB) via hydrosilylation reaction in presence of a Pt catalyst. The phenyl groups present in divinylbenzene act as the major carbon source in the final ceramics. Correlating the mixed SiOC stoichiometry composition with initial charging capacity points out a linear trend in capacity increase with amount of mixed bond networks. Mixed SiOC compositions has been characterized using 29Si MASNMR studies. It has been shown that the composition changes with pyrolysis temperature. With increase in pyrolysis temperature there is a phase separation in to SiO4 and SiC4 phases with the consumption of mixed SixOyCz units. Electrochemical studies reveal that 1000 °C is the optimal temperature of pyrolysis to have maximum SiOC capacity with good cycling stability. A specific capacity of ~600 mAh g-1 is recorded at a rate of C/20 (18 mA g-1) with 60 % efficiency. Pyrolysis atmosphere also plays a role in determining the final properties. Using a hydrogen containing atmosphere (Ar/H2 with 5% H2) for pyrolysis helps to increase the specific capacity up to an extent by removing carbon dangling bonds which acts as a trap for irreversible Li storage. This has been well supported by EPR investigations showing reduced defect concentration for H2 pyrolysed samples. A capacity increase of around 150 mAh g-1 is observed for the H2 pyrolysed samples. Recently our research focus turned to porous SiOC ceramic as a perspective anode for high rate Li storage applications. The porous nature of the anode material can enhance the fast charging/discharging behavior by reducing the diffusion path of Li ions due to electrolyte penetration and also the porous space can accommodate the volume changes associated with large Li intake. Aerogel approach is followed to produce SiOC ceramics with controlled porosity. The crosslinking is carried out under highly diluted conditions using acetone as solvent (80 vol% dilution). Wet gels after cross-linking are then aged in respective solvent followed by drying under supercritical conditions using liquid carbon dioxide followed by pyrolysis at 1000 °C under controlled argon atmosphere. Final SiOC ceramic aerogels have ~ 40 wt % of free carbon distributed within remaining SiOC matrix. The BET surface area for aerogel sample equals 180 m2/g. Electrochemical characterization of aerogels reveals a high specific capacity of more than 600 mAh g-1 at a charging rate of C (360 mA g-1) along with a good cycling stability compared to ~300 mAh g-1 recorded for dense SiOC at the same rate and ~400 mAh g-1 for H2 pyrolysed counterparts. Electrochemical studies with different SiOC compositions reveal the excellent Li host properties of these materials. Capacities are enhanced by tailoring the structure and composition of final ceramic. Incorporating Li active hetero elements such as metallic Si, Sn etc. in aerogels may further improve the Li storage performance, i.e. porous matrix can be used to compensate the volume expansion associated with the alloying systems. Figure 1

Influence of bulk fibre properties of PAN-based carbon felts on their performance in vanadium redox flow batteries

Polyacrylonitrile (PAN)-based carbon felts with different fibre properties were studied in terms of their suitability as porous flow-through electrode materials in all vanadium redox flow batteries. The crystallinity and their bulk hetero element content (in particular nitrogen) of the carbon fibres was shown to produce a significant effect on the electrocatalytical properties of the electrodes towards vanadium species. Similar effects were seen on the capacity losses associated with concomitant hydrogen evolution. Adjustments of fibre properties offer the potential of manufacturing improved electrode materials, potentially without additional steps such as surface activation or decoration with catalytically active species.

A new method to graft titania using Grignard reagents

A new method to graft titania with organic groups has been developed. In contrast to common condensation based grafting methods, this method uses organometallic chemistry to bond organic groups directly at the surface. Thereby the introduction of hetero elements at the bonding interface is avoided.

Neue molekulare Indium‐Zinn‐Sauerstoff‐ und Indium‐Zinn‐Natrium‐Sauerstoff‐Chlor‐Cluster

AbstractAbstract. The five‐membered heteroelement cluster THF·Cl2In(OtBu)3Sn reacts with the sodium stannate [Na(OtBu)3Sn]2 to produce either the new oxo‐centered alkoxo cluster ClInO[Sn(OtBu)2]3 (1) (in low yield) or the heteroleptic alkoxo cluster Sn(OtBu)3InCl3Na[Sn(OtBu)2]2 (2). X‐ray diffraction analyses reveal that in compound 1 the polycyclic entity is made of three tin atoms which together with a central oxygen atom form a trigonal, almost planar triangle, perpendicular to which a further indium atom is connected through the oxygen atom. The metal atoms thus are arranged in a Sn3In pyramid, the edges of which are all saturated by bridging tert‐butoxy groups. The indium atom has a further chloride ligand. Compound 2 has two trigonal bipyramids as building blocks which are fused together at a six coordinate indium atom. One of the bipyramids is of the type SnO3In with tert‐butyl groups on the oxygen atoms, while the other has the composition InCl3Na with chlorine atoms connecting the two metals. The sodium atom in 2 has further contacts to two plus one alkoxide groups which are part of a[Sn(OtBu)2]2 dimer disposing of a Sn2O2 central cycle. The hetero element cluster in 2 thus combines three closed entities and its skeleton SnO3InCl3NaO2Sn2O2 consists of three different metallic and two different non‐metallic elements.

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers.

Aryl polyphosphonates (ArPPN) have been demonstrated to function in wide applications as flame retardants for different polymer materials, including thermosets, polycarbonate, polyesters and polyamides, particularly due to their satisfactory thermal stability compared to aliphatic flame retardants, and to their desirable flow behavior observed during the processing of polymeric materials. This paper provides a brief overview of the main developments in ArPPN and their derivatives for flame-retarding polymeric materials, primarily based on the authors’ research work and the literature published over the last two decades. The synthetic chemistry of these compounds is discussed along with their thermal stabilities and flame-retardant properties. The possible mechanisms of ArPPN and their derivatives containing hetero elements, which exhibit a synergistic effect with phosphorus, are also discussed.