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Modeling solvation dynamics and properties is crucial for developing electrolytes for electrochemical energy storage and conversion devices. This work reports an on-the-fly multi-objective Bayesian optimization (OTF-MOBO) method to parameterize force fields for modeling ionic solvation structures, thermodynamics, and transport properties using molecular dynamics simulations. By leveraging solvation-free energy and solvation radii as training data, we employ the data-driven OTF-MOBO algorithm to actively optimize the force field parameters. The modeling accuracy was evaluated in molecular dynamics simulations until the Pareto front in the parameter space was reached through minimized prediction errors in both solvation-free energy and solvation radii. Using transition metal redox ions (Fe3+/Fe2+, Cr3+/Cr2+, and Cu2+/Cu+) in aqueous solution as examples, we demonstrate that simple force fields combining the Lenard–Jones potential and Coulombic potential can achieve relative error below 2% in both solvation free energy and solvation radii. The optimized force fields can be further extrapolated to predict solvation entropy and diffusivities with relative error below 10% compared with experiments. [ABSTRACT FROM AUTHOR]

The spin control possibility and its application in optoelectronic devices began an intensive research into its utilization, in particular, in the wide-gap semiconductors such as GaN doped with transition metal ions. Due to a strong p–d hybridization in Ga1−xMnxN, the Curie temperature above 300 K was already expected for x = 5%, providing that the free hole concentration necessary for the hole-mediated ferromagnetism exceeds 1020 cm−3. In this context, the development of non-equilibrium techniques enabled the engineering high-quality epitaxial layers of (Ga,Mn)N exhibiting uniform ferromagnetism at low-end cryogenic temperatures. The Tutorial is focused on the molecular beam epitaxy growth method of the Mn-enriched GaN magnetic semiconductors, summarizes the (Ga,Mn)N structural and electronic studies, and explains fundamental ferromagnetic properties, including the determination of the Mn concentration and the Curie temperature based on magnetic measurements. Most studies reveal the homogenous substitution of Mn3+ ions in the GaN matrix. Nevertheless, achieving room-temperature ferromagnetism still remains a challenge. Therefore, in the Tutorial, future research is suggested that can help obtain the homogenous ferromagnetism in (Ga,Mn)N at much elevated temperatures. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the properties of transition metal (TM)-doped α - G a 2 O 3 using first-principles calculations and Monte Carlo simulations. α - G a 2 O 3 is a wide-bandgap semiconductor material with enhanced performance and lower fabrication costs on sapphire substrates compared to β - G a 2 O 3 . Doping with TMs can modify electrical transport, optical absorption, and magnetic properties, yet theoretical studies on this are scarce. Our study focused on V, Cr, Mn, and Fe impurities. We introduced a newly proposed scheme for efficiently determining the ground-state defect configuration during structural relaxation. We adopt a recent, novel image charge correction method to accurately calculate formation enthalpy and thermodynamic transition levels for spin-polarized transition metal ion doping, without employing the empirical dielectric constant. Results showed Cr ions tend to neutral substitutional Ga, while V, Mn, and Fe impurity ions tend to carry a negative charge in common n-type α - G a 2 O 3 . Magnetic moments and spin-splitting impurity levels primarily arise from transition metal impurities and their d orbitals. We used the generalized four-state method to calculate exchange interaction constants between substitution lattice sites and identified (anti) ferromagnetic couplings at specific distances in a 120-atom supercell, which are negligible in total energy calculations. Monte Carlo simulations indicated a Curie temperature of 360 K in n-type α - G a 2 O 3 : Mn system with 12.5% doping, suggesting intrinsic ferromagnetic ordering based on the Heisenberg model. Our study contributes to understanding TM-doped α - G a 2 O 3 electronic structure and magnetic properties through improved methodologies. The approach can be applied in research involving other TM-doped oxides or wide-bandgap semiconductors. [ABSTRACT FROM AUTHOR]

Mullite-type glass ceramics (GCs) are a promising solid-state luminescence matrix material due to their excellent stability and abundant Al-O polyhedral structural units for accommodating active transition metal ions. In this work, Mn2+ activated Al 4 B 2 O 9 GCs were prepared by the melt-quenching method and subsequent heat treatment. Our results show that the prepared GC samples exhibit four different luminescence peaks under 360 nm excitation, corresponding to the Mn2+ ions located at [AlO 4 ] and [AlO 6 ] coordination sites of Al 4 B 2 O 9 grains and glass matrix. Both the concentration of Mn2+ and crystallinity of Al 4 B 2 O 9 crystals affect the emission spectra of the GC. The obtained GCs with good resistance for thermally induced luminescence quenching and moisture tolerance could be used in customizing LEDs with tunable emission characateritics. [ABSTRACT FROM AUTHOR]

The introduction of 0.6 TPFPB to the baseline can not only facilitate the electrochemical performance of Half-cell, but also enhance the stabilize the properties of Full cells, meanwhile resulting in the formation of superior B- and F-CEI layer. [Display omitted] • 1 TPFPB can enhance the cycling stability of the NCM811-Li half-cells or NCM811-graphite full-cells at high voltage. • Even at 60 ℃ and high voltage, the electrochemical stability of the TPFPB-containing NCM811-graphite full-cell had also been improved. • The CEI interfacial film of the cells containing TPFPB is more uniform and dense after cycling at 4.5 V. • The TPFPB molecules have the lowest LUMO values and higher HOMO values, which is able to prioritize redox reactions and participate in the formation of CEI films. • TPFPB has the lowest binding energy with Li+, which can reduce the de-solvation process of Li+, and have the highest binding energy with Co4+. Broadening the charging and discharging voltage window of high nickel cathode material NCM811 is the most expected method to improve the high specific energy density of batteries currently, yet the cathode-electrolyte interface (CEI) formed by the oxidized and decomposed products of carbonate-based electrolyte under high voltage are always so unsatisfied. Therefore, a voltage-stabilizer, TPFPB (Tris(pentafluoro)phenylborane), added into baseline electrolyte (1 M LiPF 6 in EC:EMC:DMC=1:1:1 vol%) to promote the electrochemical performance of the battery at 4.5 V. The results interpret that the TPFPB-contained NCM811-Li half-cells exhibit high specific capacity (167.10 mAh/g), excellent capacity retention rate (CRR) (75.37 %), and high rate performance (173.3 mAh/g at 5C) during 4.5 V. Meanwhile, through the analysis of the physical characterization techniques. the B- and F-rich interfacial layer, named as CEI film, existing at the interface between the cathode and the electrolyte, produced under 4.5 V, is superior, resulting in impeding the structural collapse of the cathode material and the continued dissolution of transition metal ions (TM n+) from the cathode material, as well as, ameliorate the electrochemical polarization of the battery, ultimately, it can stabilize the electrochemical performance of the battery under high voltage. Therein, the present work elucidate a new and substantial approach to enhance the high-voltage performances of rich-Ni cathode materials. [ABSTRACT FROM AUTHOR]

Designing high‐performance electrocatalysts with superior catalytic activity and stability is essential for large‐scale hydrogen production via water electrolysis. Heterostructure nanoarrays are promising candidates, though achieving both high activity and stability simultaneously, especially under high current densities, remains challenging. To this end, we have developed a cascade reaction process that constructs a series of heterostructure nanoarrays with rich heterointerfaces. This process involves treating nickel foam (NF) with molten KSCN and transition metal salts. Initially, NF reacts with KSCN to form Ni9S8 nanoarrays and S2− ions, which are subsequently captured by transition metal ions to form sulfides that are directly integrated onto the nanoarrays, resulting in abundant heterointerfaces. Both experimental and theoretical results indicate that these rich heterointerfaces significantly enhance the interfacial interaction between Ni9S8 and RuS2 within the nanoarrays (termed RH‐Ni9S8/RuS2), markedly improving both the intrinsic activity and stability for the hydrogen evolution reaction (HER). Impressively, the RH‐Ni9S8/RuS2 demonstrates exceptional HER performance, achieving a low overpotential of just 180 mV at 1000 mA cm−2 and maintaining stability for up to 500 h under such high‐current‐density conditions. This innovative approach paves the way for the interfacial design and synthesis of high‐performance catalysts for ampere‐level hydrogen production. [ABSTRACT FROM AUTHOR]

Transition-metal-containing zeolites have wide-ranging applications in several catalytic processes including the selective catalytic reduction (SCR) of NOx species. To understand how transition metal ions (TMIs) can effect NOx reduction chemistry, both structural and mechanistic aspects at the atomic level are needed. In this review, we discuss the coordination chemistry of TMIs and their mobility within the zeolite framework, the reactivity of active sites, and the mechanisms and intermediates in the NH3-SCR reaction. We emphasise the key relationship between TMI coordination and structure and mechanism and discuss approaches to enhancing catalytic activity via structural modifications. [ABSTRACT FROM AUTHOR]

Polyphenols form nanofilms with transition metal ions by coordination‐driven assembly. The as‐formed metal‐polyphenol nanofilms can degrade in the presence of chelating ligands that exhibit high stability constant with the nanofilm‐forming metal ions. We have demonstrated the degradation of Fe(III)‐tannic acid nanofilms with hydroxyketone ligands, such as maltol, kojic acid, and deferiprone, which exhibit high availability and excellent cytocompatibility. The concentration screening experiments have been performed with different ligand concentrations ranging from 1 mM–25 mM. It is important to note that only deferiprone degrades Fe(III)‐TA nanofilms even at 1 mM, and it retains the degradation activity at pH 7.4. The characteristic degradation activity of hydroxyketone ligands to Fe(III)‐TA nanofilms may depend upon their pKa value and stability constant. The degradation studies herein are attractive for the development of biomedical applications utilizing metal‐polyphenol nanofilms as a sacrificial template. [ABSTRACT FROM AUTHOR]

The combination of high‐voltage Ni‐rich cathodes and high‐capacity Si‐based anodes can result in high energy density for next‐generation batteries. However, the practical capacities accesses are severely hindered by unstable electrode/electrolyte interphases (EEI) and irreversible structural degradation, which necessitates efficient additives in electrolyte for generating stable EEI. Herein, a multifunctional additive, 3‐Fluoro‐5‐(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)picolinonitrile (FTDP) is proposed to construct robust interfaces at both cathodic and anodic surface, so as to enhance electrochemical performance. FTDP is preferentially decomposed to form B‐contained and cyano (CN) group‐rich cathode electrolyte interphase (CEI), as well as LiF‐, Li3N‐rich solid electrolyte interphase (SEI), simultaneously, resulting in the integrity and stability of electrodes. Moreover, the FTDP‐derived CEI can suppress transition metal ions dissolution, further facilitating battery cyclability. The multifunctionality of FTDP, including quenching free radicals, alleviating the hydrolysis of LiPF6 and inhibiting HF generation, thus greatly improving interfacial stability. With trace addition of 0.2 wt.%, NCM811/Li cell can be performed at an extreme condition, i.e., ultra‐high voltage (4.8 V), high temperature (60 °C) and high rate (10C). 1.6 Ah NCM811/SiOx pouch cell delivers a high capacity retention of 84.0% after 300 cycles. [ABSTRACT FROM AUTHOR]

This work reviews new ideas developed in the last two decades which play a key role for understanding the optical properties of insulating materials containing transition metal (TM) cations. Initially, this review deals with compounds involving d4 and d9 ions where the local structure of the involved MX6 complexes (M=dn cation, X=ligand) is never cubic but distorted, a fact widely ascribed to the Jahn‐Teller (JT) effect. Nevertheless, that assumption is often wrong as the JT coupling requires an orbitally degenerate ground state in the initial geometry a condition not fulfilled even if the lattice is tetragonal. For this reason, the equilibrium geometry of d4 and d9 complexes in low symmetry lattices, is influenced by two factors: (i) The effects, usually ignored, of the internal electric field, ER, due to the rest of lattice ions on the active electrons localized in the MX6 unit. (ii) The existence of structural instabilities driven by vibronic interactions that lead to negative force constants. As first examples of these ideas, we show that the equilibrium structure, electronic ground state of KZnF3:Cu2+, K2ZnF4:Cu2+ and K2CuF4 obey to different causes and only in KZnF3:Cu2+ the JT effect takes place. These ideas also explain the local structure and optical properties of CuF2, CrF2 or KAlCuF6 compounds where the JT effect is symmetry forbidden and those of layered copper chloroperovskites where the orthorhombic instability explains the red shift of one d−d transition under pressure. In a second step, this review explores stable systems involving d3, d5 or d9 cations, where the internal electric field, ER, is responsible for some puzzling phenomena. This is the case of ruby and emerald that surprisingly exhibit a different color despite the Cr3+‐O2− distance is the same. A similar situation holds when comparing the normal (KMgF3) and the inverted (LiBaF3) perovskites doped with Mn2+ having the same Mn2+‐F distance but clearly different optical spectra. The role of ER is particularly remarkable looking for the origin of the color in the historical Egyptian Blue pigment based on CaCuSi4O10. [ABSTRACT FROM AUTHOR]

Given the widespread and diverse effects of transition metal ions such as copper and zinc in multiple biological processes, this research endeavor addresses herein the microwave‐aided synthesis of two novel tetradentate ONNO (L1) and tridentate NNO (L2) donor Schiff base ligands derived from 4,5‐dimethyl‐1,2‐phenylenediamine and 4‐bromo‐2‐hydroxybenzaldehyde in a 1:2 ratio and from 4,5‐dimethyl‐1,2‐phenylenediamine and 5‐methoxy‐2‐hydroxybenzaldehyde in a 1:1 ratio, with their respective zinc, ZnL1(1) and ZnL2(3), and copper, CuL1(2) and CuL2(4), Schiff base metal complexes, which are comprehensively characterized utilizing physiochemical and analytical techniques, along with geometry optimization using the DFT approach. Spectrophotometric analyses have been used to assess the biomimetic activity in the conversion of 3,5‐DTBC to 3,5‐DTBQ with turnover numbers 53.4 and 78 h−1 in methanol for 2 and 4, whereas the zinc complexes are found to be ineffective. With CT‐DNA, possible modes of interaction with the synthesized complexes have been explored using absorption spectroscopy, where the associated binding constants ranged between 1.541 × 105 and 2.186 × 105 M−1. EtBr‐bound DNA was used in the fluorescence quenching experiments with Stern–Volmer constant (Ksv) values in the range 4.084 × 104 and 3.402 × 104 M−1, showing a stronger association with CT‐DNA. The compounds' ability to inhibit bacterial strains was also examined in vitro, as well as their ability to reduce inflammation, through the protein denaturation method and the DPPH assay for antioxidant activity have been performed. Furthermore, molecular docking simulations have been carried out to obtain a deeper comprehension of the molecular‐level interactions with CT‐DNA and cyclooxygenase‐2 (COX‐2). [ABSTRACT FROM AUTHOR]

2‐Aminophenol‐based Schiff bases and their metal complexes have drawn a lot of interest because of their wide range of biological activity and their uses in several fields. These Schiff bases are synthesized through the condensation of 2‐aminophenol and various carbonyl compounds, and metal complexes formed easily by coordinating Schiff bases with transition metal ions possess a wide range of intriguing properties that have rendered them promising candidates in biomedical research. These compounds have a diverse array of captivating biological properties including antibacterial, antifungal, anticancer, and antioxidant actions. Their versatile nature and potential for tailored modifications hold the promise for innovative biomedical applications. Compared to standard antibiotics and other studied compounds, C2, C8–C11, and C116 complexes, along with L16 and L17 ligands, exhibit the highest antibacterial activity, while C3 and C115 complexes demonstrate the highest antifungal activity. The metal chelate formation of the ligands enhanced the antimicrobial activity by increasing their lipophilic nature. C66, C76, and C112 complexes and L39 ligand showed higher anticancer activity than standard anticancer drugs. The metal complexes have higher anticancer activity than the ligand due to improved permeability and cellular uptake. The anticancer activity of the complexes is related to the substituents of the Schiff base ligands. In compounds containing an electron‐withdrawing group (e.g., Cl or Br or NO2), the activity is obviously better than others. Ligands L1–L3 and L5, L6, and L32 demonstrated the most potent antioxidant activity, surpassing both metal complexes and standard conventional antioxidants. The ligands showed greater antioxidant activity than the metal complexes due to their capability of donating free protons to scavenge free radicals. More study is needed to fully explore the potential of 2‐aminophenol‐based Schiff bases and their transition metal complexes for the development of new drugs. This review summarizes different synthetic methods, biological activities, and the structure–activity relationship. This study aims to conduct further research on 2‐aminophenol‐based Schiff bases and their metal complexes. [ABSTRACT FROM AUTHOR]

Barium strontium titanate (BST) is a perovskite material, which is used directly in various applications including thermistors, electromechanical actuators, sensors and ceramic capacitors. Here, we have investigated the impact of dopant (Mn and Co) on synthesized BST nanoparticles and its morphological, structural, vibrational and optical properties have been investigated through scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), FTIR and Raman spectroscopies. SEM image showed the nearly spherical grain for pure BST and doped (Mn and Co) BST samples. The estimated particles were strongly influenced by different dopants, in addition, Mn-doped BST showed maximum grain growth for pure and Co-doped BST samples. XRD patterns have been employed to investigate the microstructural parameters (phase, lattice, crystallite size, strain, dislocation density, etc.). The crystallite sizes have been estimated using the Scherrer formula, showing maximum crystallite size for Mn-doped BST ceramics. Recorded FTIR spectra showed the transmission peak, which is centred at wavenumber of 470 cm−1 (pure BST), was shifted to 1250 cm−1 with Mn-doped BST. Raman spectra exhibited the increased number of modes from pure BST to Mn-doped BST sample. PL showed the emissions bands, which were observed at 602–659 nm. Here, the peak shifted towards higher wavelength from pure BST to Mn-doped BST (red shifting from pure to Mn-doped BST). It revealed that the prepared samples can be employed as suitable photoluminar material. [ABSTRACT FROM AUTHOR]

The surface modification of Li1.2Mn0.54Ni0.13Co0.13O2 cathode material is carried out by heat treatment of the mixtures of Mn0.75Ni0.25C2O4 and (NH4)2SO4 absorbed on the surface of Li1.2Mn0.54Ni0.13Co0.13O2 material. The structural analysis by XRD, XPS, FTIR, and Raman spectroscopy demonstrates that Li2SO4 and metal oxides exist in the coating layer. The loading of coating layer and the calcination temperature play a crucial role in the initial Coulomb efficiency and cyclic stability of Li1.2Mn0.54Ni0.13Co0.13O2 cathode material. Compared with the pristine and metal oxide-coated sample, modified Li1.2Mn0.54Ni0.13Co0.13O2 with Li2SO4 coating exhibits higher first discharge specific capacity (233 mAh g−1 at 0.1 A g−1) and longer cyclic stability (retention of 94.7% at 1 A g−1). The enhancement of the electrochemical performance can be attributed to the increased reversibility Mn3+/Mn4+ redox reaction and the reduced irreversible migration of transition metal ion. [ABSTRACT FROM AUTHOR]

The high-entropy selenides derived from Prussian blue analogues were selenated by the vapor infiltration method, resulting in the formation of a core–shell structured high-entropy selenides (HESe-6). As a result, the HESe-6 anode for SIBs can achieve excellent cyclability (107 % retention over 1000 loops at 1 A g−1), and remarkable rate capability (606.8 mAh g−1 at 5 A g−1). [Display omitted] Transition metal selenides (TMS) have received much attention as anode materials for sodium-ion batteries (SIBs) because of their high theoretical capacity and excellent redox reversibility. However, their further development is constrained by the dissolution of transition metal ions and substantial volume changes experienced during cycling. Herein, the high-entropy Prussian blue analogues were selenized by the vapor infiltration method, resulting in the formation of a core–shell structured high-entropy selenides (HESe-6). The core–shell structure with voids and abundant selenium vacancies on the surface effectively mitigates bulk expansion and enhances electronic conductivity. Furthermore, the high-entropy property endows an ultra-stable crystal structure and inhibits the dissolution of metal ions. The ex-situ EIS and in-situ XRD results show that HESe-6 is able to be reversibly transformed into highly conductive ultrafine metal particles upon Na+ embedding, providing more Na+ reactive active sites. In addition, despite the incorporation of up to seven different elements, it exhibits minimal phase transitions during discharge/charge cycles, effectively mitigating stress accumulation. HESe-6 could retain an ultralong-term stability of 765.83 mAh g−1 after 1000 loops even at 1 A g−1. Furthermore, when coupled with the Na 3 V 2 (PO 4) 2 O 2 F cathode, it maintains a satisfactory charge energy density of 303 Wh kg−1 after 300 cycles, which shows promising application prospect in the future. [ABSTRACT FROM AUTHOR]

Ruddlesden-Popper (RP) transition-metal oxides belong to a versatile class of functional materials whose electronic properties can be tuned by varying chemical composition in a wide range. However, the relation between chemical composition and electronic properties of multi-metal RP oxides, in particular taking into account different distributions of metal ions in the lattice, has not been investigated systematically so far. In this work, we use density-functional theory (DFT) to explore the compositional dependence of electronic, magnetic, and structural properties of La 2 - x Sr x Co 1 / 2 Fe 1 / 2 O 4 oxide series for x = 0, 1, 2. To account for localized nature of transition-metal d-orbitals, self-consistent DFT+U approach Agapito-Curtarolo-Buongiorno-Nardelli (ACBN0) is employed. We show that widely used electronic-structure-based descriptors of oxygen-defect formation energies, oxygen transport, and catalytic activity strongly depend on the distribution of transition metal ions. Nevertheless, the distribution-averaged and ground-state descriptor values for La 2 - x Sr x Co 1 / 2 Fe 1 / 2 O 4 are found to depend monotonically on the composition x. In addition, we showed that in complex systems such as multi-metal Ruddlesden-Popper phases, Hubbard U values for the same species vary significantly between crystallographically non-equivalent sites. [ABSTRACT FROM AUTHOR]

Ruddlesden-Popper (RP) transition-metal oxides belong to a versatile class of functional materials whose electronic properties can be tuned by varying chemical composition in a wide range. However, the relation between chemical composition and electronic properties of multi-metal RP oxides, in particular taking into account different distributions of metal ions in the lattice, has not been investigated systematically so far. In this work, we use density-functional theory (DFT) to explore the compositional dependence of electronic, magnetic, and structural properties of La 2 - x Sr x Co 1 / 2 Fe 1 / 2 O 4 oxide series for x = 0, 1, 2. To account for localized nature of transition-metal d-orbitals, self-consistent DFT+U approach Agapito-Curtarolo-Buongiorno-Nardelli (ACBN0) is employed. We show that widely used electronic-structure-based descriptors of oxygen-defect formation energies, oxygen transport, and catalytic activity strongly depend on the distribution of transition metal ions. Nevertheless, the distribution-averaged and ground-state descriptor values for La 2 - x Sr x Co 1 / 2 Fe 1 / 2 O 4 are found to depend monotonically on the composition x. In addition, we showed that in complex systems such as multi-metal Ruddlesden-Popper phases, Hubbard U values for the same species vary significantly between crystallographically non-equivalent sites. [ABSTRACT FROM AUTHOR]

Conventional electrocatalytic water electrolysis (WE) technology has long been hindered by the slow kinetics of anodic oxygen evolution reaction (OER). It is then thermodynamically more favorable to replace OER with methanol oxidation reaction (MOR), which enables lower energy consumption and higher efficiency for hydrogen production. For such emerging methanol-coupled WE systems, it is pressing to develop efficient, stable and low-cost electrocatalysts for MOR as well as hydrogen evolution reaction (HER). Herein, an O-terminated Ti 3 C 2 T x MXene (Ti 3 C 2 O x) supported sulfur-doped NiCo layered double hydroxide (termed NiCo–SOH/Ti 3 C 2 O x) heterostructure is developed by termination modulation and surface sulfurization techniques. The NiCo–SOH/Ti 3 C 2 O x catalyst achieves an excellent MOR activity with E j10 potential of only 1.290 V, much lower than the corresponding OER potential (1.456 V) under the same test condition, validating the significant advantage of MOR over OER. Furthermore, the Tafel slope for MOR is only 47 mV dec−1 for NiCo–SOH/Ti 3 C 2 O x catalyst, far surpassing that (145 mV dec−1) for IrO 2 benchmark. The electronic interaction between S2− and transition metal ions, as well as the superior conductive capability of Ti 3 C 2 O x substrate synergistically generate highly efficient NiCo active sites and accelerate the charge transfer process, leading to high MOR activity for NiCo–SOH/Ti 3 C 2 O x. In addition, the NiCo–SOH/Ti 3 C 2 O x catalyst demonstrates a remarkably high stability for MOR and a good HER activity. Based on the excellent MOR/HER activity and stability of NiCo–SOH/Ti 3 C 2 O x , the NiCo–SOH/Ti 3 C 2 O x ||NiCo–SOH/Ti 3 C 2 O x symmetrical methanol-water co-electrolysis cell shows a low termination voltage of only 1.389 V at 10 mA cm−2 and excellent stability without obvious degradation, remarkably superior to the traditional water electrolyzer. [Display omitted] • NiCo–SOH/Ti 3 C 2 O x heterostructure as MOR/HER bifunctional electrocatalyst for water electrolysis. • NiCo–SOH/Ti 3 C 2 O x achieves excellent MOR activity with low E j10 potential of 1.290 V. • Electronic interaction and high conductivity synergistically contribute to high activity and stability for NiCo–SOH/Ti 3 C 2 O x. • The NiCo–SOH/Ti 3 C 2 O x catalyst retains 96% of its original current after 10 h of MOR chronoamperometry. • NiCo–SOH/Ti 3 C 2 O x.||NiCo–SOH/Ti 3 C 2 O x symmetrical cell shows a low termination voltage of 1.389 V in methanol-water co-electrolysis. [ABSTRACT FROM AUTHOR]

The unique radiation response of the anion-excess sublattice of bixbyite Gd 2 Ce 2 O 7 , which remains crystalline without amorphization, has sparked significant interest in exploring other systems with anion-excess bixbyite structures. This study delves into the effects of introducing transition metal ions (Cr, Mn, and Fe), luminescent activators (Eu, Tb), and trivalent bismuth with stereochemically active lone pair on the structure, optical, and luminescent properties of anion-excess bixbyite structured (In 0.60 Zr 0.40) 2 O 3+δ by synthesizing the samples using a solution combustion route. Introducing up to 20 mol % of transition metal ions (in place of indium) did not alter the superstructure of (In 0.60 Zr 0.40) 2 O 3+δ except for chromium. (In 0.60 Zr 0.40) 2 O 3+δ could take up only 5 mol % of Eu, Tb, and Bi, retaining the superstructure. Fe and Mn in the doped samples existed in the +3- state. The optical bandgap narrowing occurred in the transition metal ion-doped sample and widened in the Eu and Tb-doped samples. Co-doping Bi with Eu and Tb resulted in significant optical bandgap reduction. Typical red and green emissions have been observed in the case of Eu- and Tb-doped samples both at 293 and 77 K. Low-temperature measurements at 77 K in the case of Eu3+- doped sample indicated its occupancy at 8 b and 24 d sites of the bixbyite structure serving as valuable site probes. The CIE coordinates at 293 K (0.3352, 0.3374) for the (Eu, Tb, Bi)-doped sample near the illuminant E point showed its suitability in W-LEDs, Enhancement in energy transfer from Tb3+ to Eu3+ with lowering temperature and change in color coordinates from (0.3360, 0.3374) to (0.3352,0.3374) at 77 K and 293 K, respectively was observed for the (Eu, Tb, Bi)-doped sample, illustrating color tunability with temperature. Aging experiments concluded the metastability of rare-earth and bismuth-doped samples. [ABSTRACT FROM AUTHOR]

Monensic acid is a natural polyether ionophore and is a therapeutic of first choice in veterinary medicine for the control of coccidiosis. Although known as a sodium-binding ligand, it can also form a variety of coordination species depending on experimental conditions applied. In this study, we present the crystal structures and properties of Co(II) and Mn(II) complexes of sodium monensinate (MonNa) derived from the reaction of MonNa with cobalt or manganese dinitrates. The newly obtained coordination compounds have the same composition [M(MonNa)2(NO3)2] but the transition metal ions are placed in a different environment. The two nitrate ligands behave mono- or bidentately bound in the Co(II)- and Mn(II)-containing species, respectively, while the monensinate ligands act in a similar manner through their monodentate carboxylate functions. The formed CoO4 and MnO6 units determine the geometry of the corresponding inner coordination cores of the complexes as a tetrahedron in the case of Co(II), and as a strongly distorted octahedral structure in Mn(II) species. The effect of inorganic anions on the antibacterial performance of sodium monensinate appears to be negligible, while the presence of Co(II) or Mn(II) cations preserves or enhances the activity of unmodified MonNa, which differentially affects the growth of Bacillus subtilis, Bacillus cereus, Kocuria rhizophila, Staphilococcus aureus, and Staphilococcus saprophyticus strains. [ABSTRACT FROM AUTHOR]

Efficient, stable, and inexpensive electrocatalysts are essential to overcome the high overpotential and slow kinetics of the oxygen evolution reaction (OER) process during water electrolysis applications. 2D transition metal carbides (MXene) show great potential in functional heterogeneous interface engineering for electrocatalytic OER. However, it is still a challenge to regulate the interlayer space and realize the heterogeneous layer‐by‐layer ordered embedding for MXene. Herein, a simple hydrothermal‐assisted strategy is proposed to prepare highly conductive Ti3C2Tx MXene supported by synergized Ni2+, Co2+, and Fe3+ with bilayer H2O, which significantly enlarges the interlayer distances and improves the interlayer ion concentrations. Benefiting from modulated interface chemistry, embedded metal ions undergo multi‐directional in situ growth on the MXene substrate, thereby forming a stable 0D/2D@2D nano‐hybrid material (NiFe/MX‐HT). Combining density functional theory calculations with experiments demonstrates that MXene offers a framework for electron transfer, enhances the exposure of active sites, modulates the electronic structure, and greatly reduces the energy barrier of the rate‐determining step in the process of OER. Thus, NiFe/MX‐HT requires only 230 mV to achieve 10 mA cm−2 and maintains stability even after operating at 100 mA cm−2 for 150 h. This work offers new insights into exploring various functional MXene‐based heterogeneous materials. [ABSTRACT FROM AUTHOR]

The minerals in coal contain a certain amount of metal ions, among which transition metal ions have a catalytic effect on coal spontaneous combustion (CSC). Therefore, the addition of metal ion chelating agent to coal will weaken this catalytic effect, thereby inhibiting CSC. As a class of highly effective metal ion chelating agent, two kinds of organic phosphonic acid compounds (OPAC), 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP) and 2-Hydroxyphosphonoacetic Acid (HPAA), were investigated for their inhibitory effect on CSC. First, the low-temperature oxidation experiment was performed on coal samples before and after OPAC treatment. The experimental results show that HEDP and HPAA could reduce CO generation during spontaneous combustion of coal with different metamorphic degrees. Besides, the inhibiting efficiency of HEDP on CSC is higher than that of HPAA. Then, the effects of HEDP and HPAA on the thermal properties of CSC were investigated using synchronous thermal analysis experiment. The experimental results show that HEDP and HPAA could significantly weaken the oxygen adsorption, mass loss, and heat release during the high-temperature oxidation stage of CSC and exhibit the same result that HEDP is better than HPAA. Finally, the reasons for the difference in the inhibitory effects of HEDP and HPAA were analyzed and the inhibition mechanism of them on CSC was revealed via quantum chemical calculation. The results can provide new ideas for preventing CSC and developing new inhibitors. [ABSTRACT FROM AUTHOR]

Magnesium‐based batteries have garnered significant attention due to their high energy density, excellent intrinsic safety, and low cost. However, the application process has been hindered by the high Mg2+ ions diffusion barrier in solid‐state structures and solid‐liquid interphase. To address this issue, a hybrid battery technology based on Mg anode and Fe‐based Prussian Blue Analogue cathode doped with functional transition metal ions and N═O bonds is proposed. Combined multiscale experimental characterizations with theoretical calculations, the subtle lattice distortion can create an asymmetric diffusion path for the active ions, which enables reversible extraction with significantly reduced diffusion barriers achieved by synergistic doping. The optimized cathode exhibits a working potential of 2.3 V and an initial discharge capacity of 152 mAh g−1 at 50 mA g−1. With the preferred electrolyte combined with equivalent concentration [Mg2(µ‐Cl)2(DME)4][AlCl4]2 and NaTFSI salt solution, the hybrid system demonstrates superior cycling performance over 200 cycles at a high current density of 200 mA g−1, maintaining ≈100% coulombic efficiency with superior ion dynamic. The findings are expected to be marked an important step in the further application of high‐voltage cathodes for Mg‐based hybrid batteries. [ABSTRACT FROM AUTHOR]

Herein, a core–shell structured nanocomposite with excellent electrorheological (ER) properties was successfully prepared for studying ER fluids (ERFs). First, the material was prepared by using chromium (Cr)-ion-doped Ti-based metal–organic frameworks (MOF-Ti) as a template using the solvothermal method, followed by coating with SiO 2 via hydrolysis to form Cr-MOF-Ti/SiO 2 composite. In combination with the advantages of the MOF-Ti structure, such as more active sites and a high specific surface area, doping with transition metal ions and coating with SiO 2 can effectively enhance the interfacial polarisation of the obtained Cr-MOF-Ti/SiO 2 composite and thus improve its ER performance. Analyses were conducted on the morphology, elemental composition and functional groups of the materials using scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller and dielectric analysis. The results indicate successful Cr-ion doping and SiO 2 coating. The ER performance of the composite particles was also evaluated. The results indicate that the SiO 2 -coated sample exhibits superior ER properties, including a smaller leakage current density and higher shear stress. Moreover, the SiO 2 coating enhanced the interfacial polarisation capability of Cr-MOF-Ti, as verified by the dielectric data. [ABSTRACT FROM AUTHOR]

Fluorescent sensors have emerged as powerful tools in analytical chemistry for the detection and quantification of heavy and transition metal ions in aqueous samples. These metal ions pollute the environment and cause a number of diseases, such as irritability, anaemia, muscle paralysis, neurological damage, and memory loss. Moreover, we explore the wide spectrum of applications in environmental monitoring, where these sensors enable precise detection of contaminants, as well as in biomedical fields, facilitating diagnostic and therapeutic advancements. While highlighting the exceptional progress achieved in this field, I also address the challenges and future prospects for the continued development of fluorescent sensors, emphasizing their potential to shape the future of water quality assessment and analytical chemistry. Heavy and transition metals are of great concern because of their extreme toxicity even at very low concentration and tendency to be accumulated in bodies of living organisms. During the recent years, the design and synthesis of fluorescent chemosensors for sensing environmentally and biologically relevant important metals, particularly for heavy and transition metals, is of great interest. Opon complexation with heavy and transition metals, the fluorescence intensity of these fluorescent chemosensors either quenched or enhanced. The current review paper explains various fluorescent chemosensors for determination of toxic heavy and transition metals in environmental water samples. [ABSTRACT FROM AUTHOR]

The vast majority of star-forming galaxies are surrounded by large reservoirs of gas ejected from the interstellar medium. Ultraviolet absorption and emission lines represent powerful diagnostics to constrain the cool phase of these outflows, through resonant transitions of hydrogen and metal ions. The interpretation of these observations is often remarkably difficult as it requires detailed modelling of the propagation of the continuum and emission lines in the gas. To this aim, we present a large public grid of ≈20 000 simulated spectra that includes H I Lyα and five metal transitions associated with Mg II, C II, Si II, and Fe II which is accessible online. The spectra have been computed with the RASCAS Monte Carlo radiative transfer code for 5760 idealised spherically symmetric configurations surrounding a central point source emission, and characterised by their column density, Doppler parameter, dust opacity, wind velocity, as well as various density and velocity gradients. Designed to predict and interpret Lyα and metal line profiles, our grid exhibits a wide diversity of resonant absorption and emission features, as well as fluorescent lines. We illustrate how it can help better constrain the wind properties by performing a joint modelling of observed Lyα, C II, and Si II spectra. Using CLOUDY simulations and virial scaling relations, we also show that Lyα is expected to be a faithful tracer of the gas at T ≈ 104 − 105 K, even if the medium is highly ionised. While C II is found to probe the same range of temperatures as Lyα, other metal lines merely trace cooler phases (T ≈ 104 K). As their gas opacity strongly depends on gas temperature, incident radiation field, metallicity and dust depletion, we caution that optically thin metal lines do not necessarily originate from low H I column densities and may not accurately probe Lyman continuum leakage. [ABSTRACT FROM AUTHOR]

Context: The human body contains many different types of transition metal ions, such as Zn2+, Cu2+, which are involved in many physiological processes. An excess or deficiency of these ions can cause diseases, such as Alzheimer's disease, which is closely related to the levels of these ions in the body. In-depth understanding of various physiological and pathological mechanisms related to metal ions requires understanding the interaction between metal ions and nearby amino acids at the atomic level. This article selected four transition metal ions: Zn2+, Cu2+, Fe2+, and Mn2+ and the aromatic amino acid Phe, known for its strong coordination capability, as study subjects, comprehensively examining their binding situations. The results show that there are multiple binding modes between them and Phe, and most of the binding modes involve benzene ring coordination. The coordination strength order of the four metal ions with benzene ring, carbonyl O, hydroxyl O and amino N is different. For the lowest energy structure formed by each ion with Phe, all four ions are bound to N, carbonyl O, and benzene ring. Zn2+ is combined with two C's of the benzene ring, Cu2+ with four C's of the benzene ring, and Fe2+ and Mn2+ with the benzene ring as a whole. Part of the reason for this phenomenon may be derived from the tendency of transition metal ions to reach 18e stable structures when bound to ligands. There is a strong binding force between the four ions and Phe, and the binding trend is Cu2+(-294.9 kcal/mol) > Zn2+(-261.3 kcal/mol) > Fe2+(-247.5 kcal/mol) > Mn2+(-220.2 kcal/mol). Mayer bond order analysis and molecular orbital localization analysis found that there are very strong chemical interactions between transition metal ions and surrounding atoms, especially with N and carbonyl O. Methods: Several initial structures with different coordination modes to Phe were created according to chemical intuition for each divalent cation. Then semiempirical MD simulations at GFN2 level were run on these structures. The numerous generated structures were classified according to some criteria, then representative geometries were preliminarily optimized by TPSSh/6-31G*/LanL2DZ. To get more accurate electronic energies, high-precision quantum chemistry calculations at the level of TPSSh/def2TZVPP//TPSSh/def2QZVPP were carried out on the selected low-lying structures. All the optimized structures were confirmed to be minima without imaginary frequency by performing frequency analyses. Further electronic structure analyses such as IRI, Mayer bond order, IBSI etc. were performed to get more insights into the binding between the transition metal ions and Phe. [ABSTRACT FROM AUTHOR]

2,6-Dipicolinoylbis(N,N-dialkylthioureas), H2LR, readily react with uranyl salts under formation of monomeric or dimeric complexes of the compositions [UO2(LR)(solv)] (solv = donor solvents such as H2O, MeOH or DMF) or [{UO2(LR)(µ-OMe)}2]2− (1). In such complexes, the uranyl ions are exclusively coordinated by the "hard" O,N,O or N,N,N donor atom sets of the central ligand unit and the lateral sulfur donor atoms do not participate in the coordination. Different conformations have been found for the dimeric anions. The bridging methanolato ligands and the four uncoordinated sulfur atoms can adopt different orientations with respect to the equatorial coordination spheres of the uranyl units. The presence of non-coordinated sulfur atoms offers the opportunity for the coordination of additional, preferably "soft" metal ions. Thus, reactions with [AuCl(PPh3)], lead acetate or acetates of transition metal ions such as Ni2+, Co2+, Fe2+, Mn2+, Zn2+, or Cd2+, were considered for the syntheses of bimetallic complexes. Various oligometallic complexes with uranyl units were prepared: [{UO2(LR)(μ-OMe)(Au(PPh3)}2] (2), [(UO2)3Pb2(LR)4(MeOH)2(μ-OMe)2] (3), [M{UO2(LR)(OAc)}2] (M= Zn, Ni, Co, Fe, Mn or Cd) (R = Et: 5, RR = morph: 6), or [(UO2)(NiI)2(LR)2] (7). The products were extensively studied spectroscopically and by X-ray diffraction. [ABSTRACT FROM AUTHOR]

The detection of key ions in environmental samples has garnered significant attention in recent years in the pursuit of a cleaner environment for living organisms. Bifunctional and multifunctional sensors, as opposed to single-species sensors, have emerged as a rapidly developing field. Many reports in the literature have documented the use of bifunctional sensors for the subsequent detection of metal and cyanide ions. These sensors, consisting of simple organic ligands, form coordination compounds with transition metal ions, resulting in clear visible or fluorescent changes that facilitate detection. In some cases, a single polymeric material can act as a ligand and coordinate with metal ions, forming a complex that serves as a sensor for cyanide ion detection in biological and environmental samples through various mechanisms. Nitrogen is the most dominant coordinating site in these bifunctional sensors, with the sensitivity of the sensors being directly proportional to the denticities of ligands for metal ions, while for cyanide ions the sensitivity was found independent of the denticity of the ligands. This review covers the progress made in the field over the past fifteen years (2007–2022), with most ligands detecting copper (II) and cyanide ions, but with the capability to detect other metals such as iron, mercury, and cobalt as well. [ABSTRACT FROM AUTHOR]

Prussian blue analogs (PBA) exhibit excellent potential for energy storage due to their unique three‐dimensional open framework and abundant redox active sites. However, the dissolution of transition metal ions in water can compromise the structural integrity of PBAs, leading to significant issues such as low cycle life and capacity decay. To address these challenges, we proposed a dual‐effect additive‐modified electrolyte method to alleviate such issues, introducing sodium ferrocyanide (Na4Fe(CN)6) into aqueous alkaline electrolytes. It could not only capture Zn2+ dissolved on the surface of Na1.86Zn1.46[Fe(CN)6]0.87 (ZnHCF) electrode material during the cycling process but also conduct redox reactions on the electrode surface to provide additional capacitance. Through experiments and molecular simulation calculations, it showed that Na4Fe(CN)6 can restrict the movement of Zn dissolution into the electrolyte on the electrode surface. Based on this, an asymmetric supercapacitor based on ZnHCF//activated carbon was assembled with a modified electrolyte. The assembled supercapacitor displayed a specific capacitance of 1,329.65 mF cm−2, a power density of 2,900 mW cm−2, and an energy density of 388.28 mW h cm−2. This study provides a new idea for the design and construction of stable and efficient PBA energy storage materials by inhibiting the leaching of transition metals in PBA. [ABSTRACT FROM AUTHOR]

Addressing a changing energy environment, sodium-ion batteries (SIBs) have emerged as one of the most potentially applicable energy resources in the world. Nevertheless, its further application is hindered owing to high degree of interfacial degradation and structural changes, which caused rapid capacity fading. Herein, a novel Ce modified P2-type layered structure cathode material Na 0.67 Mn 0.8 Co 0.17 Ce 0.03 O 2 @ CeO 2 is introduced, the stability of cell is improved by simultaneous bulk doping and surface coating in one scalable step. The doping of Ce4+ increases sodium ion transport rate by shrinking transition metal layer ions and expanding Na layer spacing. Irreversible phase transition can be mitigated from the stronger the bond energy between TM and O, which is conducive to the decrease in the Mn3+/Mn4+ ratio, and suppression of the Jahn−Teller distortion. Besides, the doping of larger radius Ce4+ extends the internal paths of crystal structure, which decreases the barrier of Na+, correspondingly, the Na+ diffusion rate was increased. Meanwhile, the CeO 2 coating layer effectively inhibits parasitic reactions on the surface and improves the stability of the interface. Which display excellent capacity with a remarkable retention of 86.9 % after 100 cycles at 0.5 C and outstanding discharge rate performance of 87 mA h g−1 at 20 C. This study provides a simple process to concurrently stabilize the bulk structure and interface for the future application for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Transition metal ions in coal can catalyze the oxidation of coal, reduce the activation energy of the coal-oxygen reaction, and promote spontaneous combustion. Adding a metal chelating agent to coal can form chelates with metal ions so that the metal ions lose their catalysis. A green metal chelating agent, L-malic acid (L-MA), was proposed in this study. A C600 microcalorimeter was used to study the inhibitory effect of L-MA on spontaneous coal combustion. The results show that under the same temperature-programmed conditions, the heat absorption capacity of coal treated with L-MA solution is higher than that of raw coal, but the heat release capacity of treated coal is lower. With increase in the concentration of the L-MA solution, the inhibitory effect first increased and then decreased. The maximum heat flow of raw coal is 292 mW, and the maximum heat flow of coal samples treated with malic acid is 246 mW, 237 mW, 232 mW, 240 mW and 255 mW, respectively. The maximum heat flow of 15 wt% coal sample is 20.55% lower than that of raw coal. Based on the thermal analysis, kinetic theory, and experimental data, the activation energy of each coal sample can be calculated. The activation energy of raw coal is the lowest, and the activation energy of each group first increases and then decreases with increasing L-MA concentration, which is in agreement with the law of heat flow data. Combined with the microscopic process of coal oxidation at different temperature stages, the mechanism of L-MA inhibiting spontaneous coal combustion was explored. In summary, L-MA can effectively reduce the concentration of related free radicals in the chain reaction of spontaneous coal combustion and inhibit spontaneous coal combustion. [ABSTRACT FROM AUTHOR]

The exploration of promising electrode materials with structural stability and rapid interfacial reaction kinetics is highly desirable for supercapacitors toward large‐scale applications. Herein, the synthesis of biphase‐coupled CoPSe/NiP0.24Se1.76 with multiple in‐plane heterointerfaces using the in situ topological transformation approach is presented. As a novel ternary metal phosphoselenide (TMPSe) for supercapacitor cathode that is fabricated by synchronous phosphoselenization strategy, it realizes a superior lifespan with cycling compared to conventional transition metal selenides. The depleted anti‐bonding eg* orbitals of transition metal ions (Co/Ni) in the CoPSe/NiP0.24Se1.76, as proved by preliminary theoretical calculations, strengthens the chemical bonding between Co/Ni and coordinating atoms, thereby enhancing the chemical stability. Simultaneously, the CoPSe/NiP0.24Se1.76 in‐plane multi‐heterostructures can not only alleviate the volume change during the charge–discharge process but also expose more active sites, promoting the adsorption of OH− ions, which is conducive to the rapid redox reaction kinetics of the CoPSe/NiP0.24Se1.76, and consequently, it delivers a remarkable reversible capacity and excellent long‐term cycle stability with 97.7% initial capacitance retention over 16 000 cycles. Moreover, the asymmetric supercapacitors with this cathode demonstrate outstanding rate capability and high energy density. This strategy of constructing biphase‐coupled CoPSe/NiP0.24Se1.76 by topological transformation is of great potential application for the high‐performance electrode material. [ABSTRACT FROM AUTHOR]

Electronic structure and excited state behavior is of pronounced influence on regulation of nonlinear optical (NLO) response. Herein, a serials of transition metal ions bearing different d‐electron numbers were in situ coordinated within porphyrinic metal‐organic frameworks (MOFs), creating NLO‐responsive M‐metal (metal=Fe, Co, Ni, Cu, and Zn) frameworks. It demonstrated that the NLO properties can be optimized with the increased occupancy of the d‐shell, which enhances the degree of delocalization. Specifically, the full‐filled (d10) electron configuration of Zn2+ stabilizes the electronic structure, combination with π–π* local excitation character of M−Zn, promoting charge transfer process and resulting in outstanding NLO properties. Moreover, parameters related to the nonlinear process (β, n2, Imχ(3), Reχ(3) and χ(3)) of M−Zn are calculated to be higher than those of other materials, consistent with theoretical calculations. This work paves the way for NLO modulation based on electronic analysis and provides a promising approach for constructing high‐performance NLO materials. [ABSTRACT FROM AUTHOR]

High‐performance and temperature‐resistant lithium‐ion batteries (LIBs), which are able to operate at elevated temperatures (i.e., >60 °C) are highly demanded in various fields, especially in military or aerospace exploration. However, their applications were largely impeded by the poor electrochemical performance and unsatisfying safety issues, which were induced by the severe side reactions between electrolytes and electrodes at high temperatures. Herein, with the synergetic effects of solvation chemistry and functional additive in the elaborately designed weakly solvating electrolyte, a unique robust organic/inorganic hetero‐interphase, composed of gradient F, B‐rich inorganic components and homogeneously distributed Si‐rich organic components, was successfully constructed on both cathodes and anodes, which would effectively inhibit the constant decomposition of electrolytes and dissolution of transition metal ions, thus highly enhancing the high‐temperature electrochemical performance. As a result, both cathodes and anodes, without compromising their low‐temperature performance, can operate at temperatures ≥100 °C, with excellent capacity retentions of 96.1 % after 500 cycles and 93.5 % after ≥200 cycles, respectively, at 80 °C. Ah‐level LiCoO2||graphite full cells with a cut‐off voltage of 4.3 V also exhibited superior temperature‐resistance with a capacity retention of 89.9 % at temperature as high as 120 °C. Moreover, the fully charged pouch cells exhibited highly enhanced safety, demonstrating their potentials in practical applications at ultrahigh temperatures. [ABSTRACT FROM AUTHOR]

Heterogeneous molecular cobalt (Co) sites represent one type of classical catalytic sites for electrochemical oxygen evolution reaction (OER) in alkaline solutions. There are dynamic equilibriums between Co2+, Co3+ and Co4+ states coupling with OH−/H+ interaction before and during the OER event. Since the emergence of Co2+ sites is detrimental to the OER cycle, the stabilization of high‐valent Co sites to shift away from the equilibrium becomes critical and is proposed as a new strategy to enhance OER. Herein, phosphorus (P) atoms were doped into reduced graphene oxide to link molecular Co2+ acetylacetonate toward synthesizing a novel heterogeneous molecular catalyst. By increasing the oxidation states of P heteroatoms, the linked Co sites were spontaneously oxidized from 2+ to 3+ states in a KOH solution through OH− ions coupling at an open circuit condition. With excluding the Co2+ sites, the as‐derived Co sites with 3+ initial states exhibited intrinsically high OER activity, validating the effectiveness of the strategy of stabilizing high valence Co sites. [ABSTRACT FROM AUTHOR]

Reactions of 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H2LEt) with common tellurium(IV) starting materials such as PhTeBr3 or TeBr4 yield various tellurium(IV) and tellurium(II) compounds depending on the conditions applied. Equimolar amounts of H2LEt and PhTeBr3 give the 1 : 1 complex [PhTeIVBr3(H2LEt)], while with an excess of H2LEt, the tellurium compound is partially reduced and a {PhTeII}+ building block coordinates to both sulfur atoms of H2LEt under the formation of the ion pair [PhTeII(H2LEt)][PhTeIVBr4]. Similar reactions between H2LEt and TeBr4 give the neutral monomer [TeIIBr2(H2LEt)] or the coordination polymer [TeIIBr2(H2LEt)]∞. The latter compound is also formed with the assistance of Pb2+ ions. While the lead ions do not appear in the isolated product, similar reactions with transition metal ions such as Ni2+, Mn2+, or Co2+ result in the formation of heterobimetallic complexes, in which Te(II) building blocks are directed to the sulfur atoms of the deprotonated ligand {H2LEt2‐S,S}2−, while the transition metal ions occupy central coordination positions between two of the organic ligands using the pyridine nitrogen atom, carbonyl oxygen atom(s) and/or the nitrogen atoms of the thiourea units. [ABSTRACT FROM AUTHOR]

For the first time, the magnetic and optical (bandgap) properties of co‐doped Mg/Dy, Al/Dy, and Mn/Nd SrFe12O19$\left(\text{SrFe}\right)_{12} \left(\text{O}\right)_{19}$ (SFO) at Sr and Fe sites are investigated using a microscopic model and the Green's function theory. It is shown that the co‐doping at both Sr and Fe sites can change the behavior of the magnetization which decreases by transition metal or nonmagnetic ion doping at the Fe site (with doping ions larger than the host Fe ions), but by additive co‐doping at the Sr site with rare‐earth ion (which ionic radius is smaller than that of Sr) the magnetization increases with increasing the co‐doping concentration. The bandgap energy decreases in the co‐doped SFO. The mechanism of this co‐doping effect is explained on microscopic level. It is due to the changes of the spin‐exchange interaction constants at the doped sites caused by the appearance of different strain by the doping with two ions. The theoretical results are compared with the existing experimental data and are in good qualitative agreement. [ABSTRACT FROM AUTHOR]

The structures of nine hydrated metal ions in aqueous solution have been redetermined by large angle X-ray scattering to obtain experimental data of better quality than those reported 40–50 years ago. Accurate M–OI and M–(OI–H)⋯OII distances and M–OI(H)⋯OII bond angles are reported for the hydrated magnesium(II), aluminium(III), manganese(II), iron(II), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) ions; the subscripts I and II denote oxygen atoms in the first and second hydration sphere, respectively. Reported structures of hydrated metal ions in aqueous solution are summarized and evaluated with emphasis on a possible relationship between M–OI–OII bond angles and bonding character. Metal ions with high charge density have M–OI–OII bond angles close to 120°, indicative of a mainly electrostatic interaction with the oxygen atom in the water molecule in the first hydration shell. Metal ions forming bonds with a significant covalent contribution, as e.g. mercury(II) and tin(II), have M–OI–OII bond angles close to 109.5°. This implies that they bind to one of the free electron pairs in the water molecule. Comparison of M–O bond distances of hydrated metal ions in the solid state with one hydration shell, and in aqueous solution with in most cases at least two hydration shells, shows no significant differences. On the other hand, the X–O bond distance in hydrated oxoanions increases by ca. 0.02 Å in aqueous solution in comparison with the corresponding X–O distance in the solid state. A linear correlation is observed between volume, calculated from the van der Waals radius of the hydrated ion, and the ionic diffusion coefficient in aqueous solution. This correlation strongly indicates that monovalent metal ions, except lithium and silver(I), and singly-charged monovalent oxoanions have a single hydration shell. Divalent metal ions, bismuth(III) and the lanthanoid(III) and actinoid(III) ions have two hydration shells. Trivalent transition and tetravalent metal ions have two full hydration shells and portion of a third one. Doubly charged oxoanions have one well-defined hydration shell and an ill-defined second one. [ABSTRACT FROM AUTHOR]

The electrical properties of semiconducting Oxide glasses with composition x MgO(50-x) PbO:50V2O5 glasses have been investigated. The glasses were prepared by the normal melt quenching technique. The X-ray diffractograms of the present glass system show that the prepared glass samples are perfectly amorphous. The DSC patterns indicate that the MgO-substituted glass samples behave like the eutectic composition up to x = 15 mol%. The DC conductivity is measured in the temperature range of 300 to 500 K, and data are fitted with Mott's and Schnakenberg models. The conductivity of all the glass compositions increases with increasing MgO content. The conduction mechanism of these glasses was non-adiabatic. The various parameters, such as activation energy, average site separation between transition metal ions and polaron radius, have been calculated and found consistent with Mott's small polaron hopping non-adiabatically between different sites. The Hruby parameter (kg) for this glass system has been calculated and discussed. [ABSTRACT FROM AUTHOR]

Bimetallic phosphides are considered as promising electrocatalysts for zinc–air batteries toward oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). To address the semi‐conductor inherent low electronic conductivity and catalytic activity, a polymetal‐chelated strategy is employed to in situ fabricate bimetallic nanophosphides within carbon matrix anchoring by chemical bonding. The employment of biomolecule polydopamine (PDA) efficiently anchors various transition metal ions due to its strong chelating capability via inherent functional groups. Furthermore, the chelation of multi‐metal ion is proved to promote the formation of graphitic nitrogen. The bimetallic FexCoyP phosphides nanoparticles are intimately encapsulated in carbon matrix through in situ carbonization and phosphatization processes. When utilized in Zinc–air batteries, Fe0.20Co0.80P anchored within N, P co‐doped sub‐microsphere (Fe0.20Co0.80P /PNC) exhibit a maximum power density of 167 mW cm−2 and cycle life up to 270 cycles, with a round‐trip voltage of 0.955 V. The mechanisms for catalytic activity passivation are ascribed to the etching of nitrogen and oxidation of phosphorus in carbon matrix, as well as the oxidation of the surface phosphide on the sub‐microspheres. This study presents a promising candidate for advancing the further development of energy conversation catalysis. [ABSTRACT FROM AUTHOR]

Two novel hydrophobic deep eutectic solvents (HDESs), composed of alkyl (=Hexyl, Nonan) ethylenediaminium and menthol (Men), namely Hexen/Men and Nonen/Men, were synthesized. Hexen and Nonen primarily act as hydrogen bond acceptors, with Men serving as the principal hydrogen bond donor. After the formation of HDES, the IR absorption peaks of Hexen, Nonen's–NH2, and Men–OH fused into a wider peak, the 1H-NMR spectra of Men–OH, shifted to a lower field. Furthermore, a significant redshift approximately 300 cm−1 was detected in the vibrational frequency of the Men–OH functional group when performing density functional theory (DFT) calculations for the HDESs. These results support the development of stronger O–H···N bonds between Hexen/Nonen–NH2 and Men–OH, and the calculated sum of hydrogen bonding energy was approximately 56 mol·kg–1, categorizing it as an intermediate-strength hydrogen bond. Both HDESs have ethylenediamine polar heads in their hydrogen bond acceptors, which have chelating characteristics that help them coordinate with transition metal ions. Metal ions such as Cu(II), Co(II), and Ni(II) were successfully extracted from aqueous solutions at a concentration of 10 mmol·L–1using HDESs. The Cu(II) and Ni(II) extraction efficiencies exceeded 90%, indicating their effectiveness. Notably, even at higher metal ion concentrations (100 mmol·L–1), the extraction efficiencies of all three metal ions remained consistently below 80%. This indicates that the HDESs can suitably collect trace metal ions. [ABSTRACT FROM AUTHOR]

This paper considers the data on monitoring the ionic composition of aerosol particles and small gas components in the surface atmosphere of Antwerp and Beijing in winter. According to the results of their comparison, it is shown that the rapid accumulation of in haze particles over Beijing is triggered by a liquid-phase catalytic reaction of sulfate formation involving Mn/Fe ions, which proceeds in the fast degenerate branched mode. The cycle of these transformations is accompanied by the associated production of nitrate radicals in the particles. Their release into the gas phase leads to an increase in the concentration of N2O5 molecules and a rapid accumulation of nitrates. The coupling of the catalytic (petrochemical) conversion of sulfur dioxide into sulfates and the nitrate production process over Beijing thus plays a crucial role in the formation of the mineral composition of haze particles in the atmosphere. [ABSTRACT FROM AUTHOR]

The rise of antimicrobial resistance presents a critical challenge in modern healthcare, demanding the development of innovative therapeutic agents. Metal-based antibiotics, or metalloantibiotics, have gained attention due to their enhanced biological efficacy. Schiff base metal ion complexes, a subset of metalloantibiotics have demonstrated promising antibacterial, antifungal, antiviral, and anticancer properties. This study aims to synthesize and characterize novel Schiff base metal ion derivatives to contribute to the development of next-generation antimicrobial agents. Novel Schiff base metal ion derivatives were synthesized via the condensation of aldehydes and primary amines, followed by complexation with transition metal ions. The resulting metal complexes were characterized using Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy. FTIR was used to confirm the formation of the imine group (-CH=N) and metal-ligand coordination. NMR spectroscopy provided insights into the electronic environment of the protons and carbons within the complexes. FTIR spectra confirmed the successful formation of the Schiff base complexes, indicated by the presence of characteristic imine (-CH=N) peaks and metal-ligand interactions. NMR analysis revealed shifts in chemical signals consistent with metal coordination. Biological assays indicated that the synthesized metal ion derivatives exhibited enhanced antibacterial activity compared to the unmodified Schiff base ligands, with significant inhibition zones observed against common bacterial strains. In conclusion, this research provides valuable insights into the synthesis and characterization of Schiff base metal ion derivatives. The enhanced antimicrobial activity observed in the synthesized complexes supports their potential as next-generation agents to combat bacterial resistance, offering new possibilities for drug discovery and development in medicinal chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new approach is established to adjust the surface oxygen vacancies of the cathode. • The processes of oxygen adsorption and dissociation of the CFO cathode are enhanced. • CFO-10 exhibits a MPD of 923 mW cm−2, indicating an enhancement of 78.5 %. • The R p of CFO-10 decreases by 42.8 %, reaching 0.032 Ω‧cm2. Oxygen vacancies are crucial for enhancing oxygen ion transport in solid-state materials. Therefore, an approach was established to efficiently adjust the surface oxygen vacancy concentration in the solid oxide fuel cell (SOFC) cathodes. This method employs NaBH 4 solution to capture lattice oxygen on the cathode surface, enabling precise control over both the surface oxygen vacancy concentration and the transition metal ion valence states in spinel CoFe 2 O 4 (CFO) by modulating the NaBH 4 treatment duration. The results indicate that CFO-10, treated with NaBH 4 solution for 10 min, exhibits optimal electrochemical catalytic activity. This enhancement is primarily attributed to the improved oxygen adsorption-dissociation and charge transfer processes. At 750 °C, CFO-10 shows a polarization resistance (Rp) of 0.032Ω cm2, representing a reduction of 42.8 % compared to CFO. Additionally, CFO-10 achieves a peak power density (PPD) of 923 mW·cm−2, representing a 78.5 % increase compared to CFO. This study provides new insights for optimizing SOFC spinel oxide cathode performance and opens a promising avenue for the development of other high-performance catalytic materials. [ABSTRACT FROM AUTHOR]

[Display omitted] To meet the stringent requirements of wearable and flexible electronics for functionality and comfort, it is urgent to develop green conductive, self-adhesive, and stretchable functional hydrogels. The chelates of transition metal ions and lignosulfonate sodium (LS) can impart multi-functionality to the hydrogel and significantly improve the hydrogel's gelation speed. However, the presence of metal ions may weaken the adhesiveness of hydrogels by shielding the functional adhesive groups. Here, an oxidative metal ions-free lignin-catalyzed multifunctional polyacrylic acid (PAA) hydrogel is proposed. LS itself can undergo a redox reaction with the initiator to generate many free radicals, thereby catalyzing the rapid polymerization of polymer monomers at room temperature and subsequent gelation. Furthermore, LS can easily improve the hydrogels' softness (compressive modulus: ∼7 kPa) and stretchability (maximum ∼2700 %). Interestingly, LS can simultaneously promote the hydrogel's conductivity, adhesion, and UV blocking. Notably, the hydrogel integrating these advantageous features is suitable as non-invasive electronics in the human epidermis. We explored its ability to act as adhesive bioelectrodes to collect electrooculographic signals in patients with physical and language impairments. Bioelectrodes can recognize the patient's eye movements. The displayed electrical signal can be output in 6 languages after being encoded. This provides a valuable case for LS-doped functional hydrogels in the medical field. [ABSTRACT FROM AUTHOR]

The addition of Ga as a functional additive serves to adjust the initial solvation structure and facilitate the formation of stable solid electrolyte interphase film on the cathode surface. This CEI film effectively inhibits the dissolution of transition metal ions and prevents electrolyte decomposition. As a result, Ga contributes to enhancing the high-voltage cycling stability of sodium-metal batteries. [Display omitted] In recent years, there has been notable advancement in the development of high-performance materials for sodium-ion batteries, particularly in layered oxide cathodes. However, research on enhancing the interface between electrolytes and cathodes remains nascent. One promising approach involves the addition of electrolyte additives, recognized for their cost-effectiveness and efficiency in bolstering the electrode/electrolyte interface to enhance material stability during high-voltage cycling. In this work, we investigate the use of glutaric anhydride (GA) as an electrolyte additive to improve the cycling stability of NaNi 1/3 F 1/3 M 1/3 O 2 /Na (NFM/Na) high-voltage sodium-metal batteries. Batteries using GA-containing electrolytes demonstrate impressive capacity retention: 80.51 % after 200 cycles at 4.0 V and 76.01 % after 150 cycles at 4.1 V. The research delves into the mechanistic insights behind GA's effectiveness in enhancing cyclic stability. Theoretical calculations reveal that GA plays a crucial role in modifying the structure of the first solvation shells, promoting the formation of an elastic cathode-electrolyte interface (CEI) film enriched with O C O groups. This uniform and stable CEI film effectively preserves the material's crystal structure and mitigates the dissolution of transition metals, thereby prolonging battery lifespan under demanding extremely cycling conditions. [ABSTRACT FROM AUTHOR]

Fe(III)-0.5-AP-CN photocatalysts synthesized based on a donor–acceptor structure can significantly enhance the yield of N 2 reduction to NH 3. [Display omitted] • Donor-acceptor (D-A) polymeric carbon nitride constructed by covalent binding of phenanthroline units. • Intermolecular charge transfer in the presence of D-A structure promotes the rapid migration of photogenerated carriers. • Phenanthroline units in the D-A structure are coordinated with Fe3+ ions to form special nanowire morphologies. • D-A type Fe(III)-0.5-AP-CN photocatalytic synthesis of ammonia with yields up to 825.3 μmol g−1 h−1. Constructing photocatalysts for the stable and efficient production of NH 3 is of excellent research significance and challenging. In this paper, the electron acceptor 5-amino-1,10-phenanthroline (AP) is introduced into the electron-donor graphitic carbon nitride (CN) framework by a simple heated copolymerization method to construct a donor–acceptor (D-A) structure. Subsequently, the phenanthroline unit is coordinated with transition metal Fe3+ ions to obtain the photocatalyst Fe(III)-0.5-AP-CN with better nitrogen fixation performance, and the average NH 3 yield can reach 825.3 μmol g−1 h−1. Comprehensive experimental results and theoretical calculations show that the presence of the D-A structure can induce intramolecular charge transfer, effectively separating photogenerated electrons and holes. The Fe active sites can improve the chemisorption energy for N 2 , enhance the N -Fe bonding, and better activate the N 2 molecule. Therefore, the synergistic effect between the construction of the D-A structure and the stably dispersed Fe active sites can enable CN to achieve high-performance N 2 reduction to produce NH 3. [ABSTRACT FROM AUTHOR]