Redox Decomposition Research Articles

Transesterification Induced Multifunctional Additives Enable High‐Performance Lithium Metal Batteries

AbstractThe electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3‐dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3‐dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si−O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA−) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic‐rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high‐performance electrolyte for LMBs.

Transesterification Induced Multifunctional Additives Enable High-Performance Lithium Metal Batteries.

The electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3-dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3-dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si-O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA-) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic-rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high-performance electrolyte for LMBs.

Thermodynamics of the Formation of Intermediate Complexes in the Oxidation of Citric Acid with Cerium(IV) and the Kinetics of Their Intramolecular Redox Decomposition

Thermodynamics of the Formation of Intermediate Complexes in the Oxidation of Citric Acid with Cerium(IV) and the Kinetics of Their Intramolecular Redox Decomposition

Using Synchrotron Techniques, Investigation of Electrochemical Interfaces in Ni-Rich NMC and Sulfide Electrolytes in All-Solid-State Lithium Metal Batteries

a Nano-electrochemistry Laboratory, Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, R.O.C b National Synchrotron Radiation Research Center (NSRRC), Hsinchu, 30076, Taiwan, R.O.CIn all-solid-state lithium metal batteries enable long cyclability of high voltage oxides cathode persistent problem for the large scale application as their underprivileged interfacial steadiness in contrast to sulfide solid-state electrolyte. In this context, the interfaces of the solid electrolyte and Ni-rich NMC811 active material are looked upon as interfacial chemical responses induced by delithiation. In this study, we monitor the impedance progress at the unstable electrode|electrolyte interface due to the electrochemical interfacial response and help us understand the complex nature of reactivity and degradation kinetics with the solid-solid interface redox decomposition, which makes decoupling each effect difficult. we investigated the interfacial phenomenon between LPSC and high voltage cathode NMC811. The effects of spontaneous retort by the side of the interface were separated, and the intrinsic electrochemical decomposition of LPSC was quantified. Moreover, we show that the notch of interfacial degradation surges and the presence of oxidation mechanisms. At the higher delithiation stage, the cathode might twitch structural defenselessness and oxygen utter and resulting in further stark degradation. This complex kinetic degradation behavior was investigated at the solid-solid interface in a delithiation NMC811 and SSE based on the local oxidation state of NMC811, and LPSC SE interfacial chemical response. In this work, we used various characterization techniques to investigate the interfacial phenomenon between LPSC|NMC811 combining EIS and advanced synchrotron techniques such as sXAS, XPS, XRF-XANES mapping, and In-situ Raman spectroscopy. Keywords: delithiation, Ni-rich cathode, Sulfide-solid-state electrolyte, interfacial reaction, Synchrotron XPS, XRF.

Amorphous Selenium Nanoparticles Improve Vascular Function in Rats With Chronic Isocarbophos Poisoning via Inhibiting the Apoptosis of Vascular Endothelial Cells.

AimThis study aimed to investigate the preventive effect and possible mechanism of amorphous selenium nanoparticles (A-SeQDs) on isocarbophos induced vascular dysfunction.MethodsA-SeQDs was made by auto redox decomposition of selenosulfate precursor. Male rats were given isocarbophos (0.5 mg/kg/2 days) by intragastric administration for 16 weeks to induce vascular dysfunction. During the course, A-SeQDs (50 mg/kg/day) was added to the water from week 5. Then, the rats were killed to observe and test the influence of A-SeQDs on the vascular dysfunction induced by isocarbophos. Finally, human umbilical vein endothelial cells (HUVECs) were treated with 10% DMEM of isocarbophos (100 μM) for 5 days to detect the related indexes. Before the use of isocarbophos treatment, different drugs were given.ResultsA-SeQDs could reduce total carbon dioxide, MDA, VCAM-1, ICAM-1, IL-1, and IL-6 while increasing oxygen saturation, NO content, and SOD activity in rats. A-SeQDs also resulted in relatively normal vascular morphology, and the expression of sodium hydrogen exchanger 1 (NHE1) and caspase-3 decreased in rats. Furthermore, in HUVECs treated with isocarbophos, A-SeQDs maintained mitochondrial membrane potential, inhibited the cleaved caspase-3 expression, and released cytochrome c from mitochondria to cytosol.ConclusionA-SeQDs can inhibit the apoptosis of HUVECs through the mitochondrial pathway, and effectively treat the impairment of vascular endothelial function caused by isocarbophos, which is NHE1-dependent.

Inside Back Cover: Syntheses and Characterizations of the Mixed Noble‐Gas Compounds, [FKrIIFXeIIF][AsF6]⋅0.5 KrIIF2⋅2 HF, ([KrII2F3][AsF6])2⋅XeIVF4, and XeIVF4⋅KrIIF2 (Angew. Chem. Int. Ed. 44/2021)

A mixed noble-gas cation described by Gary J. Schrobilgen and co-workers in their Research Article on page 23678 was synthesized by reaction of KrF2 and [XeF][AsF6] in liquid HF at −60 °C to form [FKrFXeF][AsF6]⋅0.5 KrF2⋅2 HF. The V-shaped [FKrFXeF]+ cation, depicted as a space station, is in geosynchronous orbit over Hamilton where [FKrFXeF]+ was created and is being carefully monitored. To the east, decay of a sister station's orbit caused the station to warm, break up, and undergo redox decomposition to [F5Xe][AsF6], XeF4, and Kr as it enters Earth's atmosphere; a rescue shuttle speeds away from the disaster zone.

Efficient technology for the extraction of non-ferrous metals from liquid production waste

The results of the study of Cu(II) to Cu(I) reduction process in chloride-sulfate solutions under the action of carbon monoxide at atmospheric pressure in the presence of palladium chloride(II) acting as catalyst are reported. This process is described by general equation: 2Cu2+ +2SO2-4 +2Cl +CO+H O- 2 →Pd(II) 2CuCl+CO +2H +2SO2 + 2-4 . It has been shown product mix in the sediment obtained hydrocarbonyl process. Thus, the recovery process Cu(II) → Cu(I) with the action of CO is catalyzed by Pd(II) in the initial stage, and then develops in an autocatalytic mode with the subsequent redox decomposition intermediate. As a reducing agent serve ligand molecules of CO which are in activated state: CO+HO=CO +2H +2e2 2 + .

Exploring the redox decomposition of ethylene carbonate–propylene carbonate in Li-ion batteries

A small difference caused by a single methyl group between EC and PC could cause a large difference in lithium alkyl carbonates.

Thermodynamic and Kinetic Aspects of the Stability of Sir P. C. Ray’s Mercurous Nitrite Compound

Different thermodynamic and kinetic aspects of the stability of mercurous nitrite discovered accidentally in 1896 by P. C. Ray’s group have been critically analysed in this review article. It has been concluded that mercurous nitrite is thermody-namically unstable but it gains the kinetic stability which may originate from the overpotential factor in the gas evolution in its redox decomposition. It may also arise from strengthening the HgI-HgI bond which undergoes cleavage at the rate determining step (rds) in the disproportionation of Hg22+ or its oxidation by the one-electron oxidant like NO2− . The Hg1-HgI bond is strengthened through the formation of the relatively weaker HgI-O bond (i.e. nitrito linkage) compared to the HgI-N bond (i.e. nitro linkage) in mercurous nitrite.

Relative kinetic stability towards redox decomposition of cerium(IV) complexes with some organic compounds

A comparative analysis is performed on the stability constants $${\upbeta }_{1yn}$$ and intramolecular redox decomposition rate constants $$k_{n\; = \;1}$$ obtained for intermediate cerium(IV) complexes $$[{\text{CeH}}_{y} {\text{L}}_{n} ]^{4\; + \;y\; - \;nk}$$ with three series of heterocyclic and aliphatic organic compounds $$R = H_{k} L$$ formed during the oxidation reactions of these compounds with cerium(IV). Linear relationships are established for these complexes between $$\log k_{n\; = \;1}$$ and $$\log {\upbeta }_{1yn}$$. A quantitative method is proposed to examine the kinetic stabilization of unstable metal oxidation states upon complexation as well as the reactivity of these complexes on the basis of the obtained equations for these relationships.

Stability Constants and Rate Constants of Intramolecular Redox Decomposition of Cerium(IV) Complexes with Certain Hydroxycarboxylic Acids in Nitrate Medium

Composition, stability constants and rate constants of intramolecular redox decomposition of cerium(IV) complexes with anions of quinic $${{\left( {{\text{CHOH}}} \right)}_{3}}{{\left( {{\text{C}}{{{\text{H}}}_{2}}} \right)}_{2}}{\text{C}}\left( {{\text{OH}}} \right)$$COOH, lactic $${\text{C}}{{{\text{H}}}_{3}}{\text{CH}}\left( {{\text{OH}}} \right){\text{COOH,}}$$ tartaric $${\text{HOOCCH}}\left( {{\text{OH}}} \right){\text{CH}}\left( {{\text{OH}}} \right){\text{COOH}}$$, and citric $${\text{HOOCC}}{{{\text{H}}}_{2}}{\text{C}}\left( {{\text{OH}}} \right)\left( {{\text{COOH}}} \right){\text{C}}{{{\text{H}}}_{2}}{\text{COOH}}$$ hydroxycarboxylic acids have been determined by spectrophotometry, photometry, pH and kinetic measurements in nitrate medium in pH range 0–3 at ionic strength $$I = 2$$ and $$295.15$$ K. A direct linear correlation between stability constant logarithms and negative logarithms of rate constants of intramolecular redox decomposition of the studied complexes, which is absent in sulfate medium, has been revealed. The noted correlation can be considered as appearance of free energy linear relationship principle in coordination chemistry.

Kinetic Description of Ascorbic Acid Decomposition in Redox Initiator Systems for Polymerization Processes

The temperature dependent redox decomposition rate constants of ascorbic acid (AsAc) in aqueous solutions were quantified in the presence of ammonium iron(III) sulfate dodecahydrate (Fe-cat) and te...

Kinetic and Thermodynamic Stability of Intermediate Complexes in the Reactions of Oxidation of Some Heterocyclic Compounds with Cerium(IV)

The kinetic and thermodynamic characteristics of intermediate cerium(IV) complexes with 8-oxyquinoline, 7-iodo-8-hydroxy-quinoline-5-sulfonic acid, and 1-phenyl-2,3-dimethyl-4-dimethylaminopyrazolone-5, which are formed at the first stage of oxidation of these heterocyclic compounds with cerium(IV), are studied by spectrophotometry, photometry, and pH-metry at ionic strength I = 2 in sulfuric acid solutions (pH 0.5–3.0) at 285.15–297.15 K. The composition of the complexes and the form in which the organic ligand is present in them are determined. The stability constants and rate constants of their intramolecular redox decomposition are identified. The general equation of the rate of redox process observed in the systems is obtained and the respective reaction model is proposed. The type of linear correlations between the thermodynamic and kinetic stability of intermediate complexes discussed in this study can be used in coordination chemistry for quantitative description of the reactions of oxidation of organic compounds with transition metal ions.

Unraveling the Operational Mechanisms of Chemically Propelled Motors with Micropumps.

The development of effective autonomous micro- and nanomotors relies on controlling fluid motion at interfaces. One of the main challenges in the engineering of such artificial machines is the quest for efficient mechanisms to power them without using external driving forces. In the past decade, there has been an important increase of man-made micro- and nanomotors fueled by self-generated physicochemical gradients. Impressive proofs of concept of multitasking machines have been reported demonstrating their capabilities for a plethora of applications. While the progress toward applications is promising, there are still open questions on fundamental physicochemical aspects behind the mechanical actuation, which require more experimental and theoretical efforts. These efforts are not merely academic but will open the door for an efficient and practical implementation of such promising devices. In this Account, we focus on chemically driven motors whose motion is the result of a complex interplay of chemical reactions and (electro)hydrodynamic phenomena. A reliable study of these processes is rather difficult with mobile objects like swimming motors. However, pumps, which are the immobilized motor counterparts, emerge as simple manufacturing and well-defined platforms for a better experimental probing of the mechanisms and key parameters controlling the actuation. Here we review some recent studies using a new methodology that has turned out to be very helpful to characterize micropump chemomechanics. The aim was to identify the redox role of the motor components, to map the chemical reaction, and to quantify the relevant electrokinetic parameters (e.g., electric field and fluid flow). This was achieved by monitoring the velocity of differently charged tracers and by fluorescence imaging of the chemical species involved in the chemical reaction, for example, proton gradients. We applied these techniques to different systems of interest. First, we probed bimetallic pumps as counterparts of the pioneering bimetallic swimmers. We corroborated that fluid motion was due to a self-generated electro-osmotic mechanism driven by the redox decomposition of H2O2. In addition, we analyzed by simulations the key parameters that yield an optimized operation. Moreover, we accomplished a better assessment of the importance of surface chemistry on the metal electrochemical response, highlighting its relevance in controlling the redox role of the metals and motion direction. Second, we focused on metallic and semiconductor micropumps to analyze light-controlled motion mechanisms through photoelectrochemical decomposition of fuels. These pumps were driven by visible light and could operate using just water as fuel. In these systems, we found a very interesting competition between two different mechanisms for fluid propulsion, namely, light-activated electro-osmosis and light-insensitive diffusio-osmosis, stemming from different chemical pathways in the fuel decomposition. In this case, surface roughness becomes a pivotal parameter to enhance or depress one mechanism over the other. These examples demonstrate that pumps are practical platforms to explore operating mechanisms and to quantify their performance. Additionally, they are suitable systems to test novel fuels or motor materials. This knowledge is extensible to swimmers providing not only fundamental understanding of their locomotion mechanisms but also useful clues for their design and optimization.

Thermal properties of four Co/Fe complexes based on amine-type and cyanido ligands

Four ionic cobalt hexacyanidoferrate(II) complexes with formulae [Co(NH3)6]4[Fe(CN)6]3·12H2O (1) [Co(NH3)6]2Cl2[Fe(CN)6]·4H2O (2), [Co(dien)2][Fe(CN)5(CNH)]·3H2O (3) and [Co(dien)2]4[Fe(CN)6]3·23H2O (4), where dien is 1,4,7-triazaheptane, have been synthetized and chemically and spectroscopically (IR and Mossbauer) characterized. X-ray single-crystal study of complex 3 revealed that its crystal structure is ionic and is built up of mer-[Co(dien)2]3+ complex cations, scarce [FeII(CN)5(CNH)]3− complex anions with one protonated cyanide group and water molecules of crystallization. The thermal properties (TG and DTA) on air of all complexes were studied. The thermal decompositions of all studied complexes are stepwise starting with dehydration at 60 (1), 130 (2), 70 (3) and 55 °C (4). Further decomposition of the respective complexes involves (with possible overlapping of the respective processes) deamination and redox decomposition of the cyanido ligands yielding metals which upon further heating are re-oxidized. The solid residue for 1 was identified using powder X-ray diffraction, SEM and EDX methods as inverse spinel oxide.

Solvent-Assisted Stepwise Redox Approach To Generate Zeolite NaA-Supported K2O as Strong Base Catalyst for Michael Addition of Ethyl Acrylate with Ethanol.

Solid base catalysts featuring green, robustness, and high activity play an important role in the current fine-chemical and petrochemical industry. Normally, the generation of supported K2O by thermal decomposition of KNO3 requires high temperature, and this process can sometimes destroy the structure of supporting materials. We herein report a solvent-assisted stepwise redox (SASR) approach to generate zeolite NaA-supported K2O, which we call K2O/NaA, that function as the solid base catalyst for Michael addition reaction between ethanol and ethyl acrylate. The solvent-assisted redox decomposition process of KNO3 at elevated temperature was investigated by thermogravimetry–mass spectrometry. It reveals that after reducing a minor amount of KNO3 at 400 °C, the organic solvent decomposes to form carbon, which promotes the reduction of KNO3 to generate strong basicity on the zeolite NaA at 600 °C. The resulting material, K2O/NaA-S, exhibits improved catalytic activity in Michael addition reaction over other benchmark base catalysts that have been used in this reaction. This catalyst is durable for at least four catalytic cycles without apparent loss in activity. K2O/NaA-S exhibits larger reaction rate constant yet lower activation energy than K2O/NaA prepared by thermal decomposition method. The SASR approach described in this paper represents a new blueprint for the generation of the supported alkali oxide as the solid base catalyst.

Designing Stability into Thermally Reactive Plumbylenes

Lead analogues of N-heterocyclic carbenes (NHPbs) are the least understood members of this increasingly important class of compounds. Here we report the design, preparation, isolation, structure, volatility, and decomposition pathways of a novel aliphatic NHPb: rac- N 2, N 3-di- tert-butylbutane-2,3-diamido lead(II) (1Pb). The large steric bulk of the tert-butylamido moieties and rac-butane backbone successfully hinder redox decomposition pathways observed for diamidoethylene and -ethane backbone analogues, pushing the onset of thermal decomposition from below 0 °C to above 150 °C. With an exceptionally high vapor pressure of 1 Torr at 94 ± 2 °C and excellent thermal stability among Pb(II) complexes, 1Pb is a promising precursor for the chemical vapor deposition (CVD) and atomic layer deposition (ALD) of functional lead-containing materials.

Thermodynamic and Kinetic Parameters of Cerium(IV) Complexes with Some Dicarboxylic Acids

The thermodynamic and kinetic parameters of the cerium(IV) complexes formed in the initial stage of oxidation of dicarboxylic acids (H2L), like pentanedioic, butanedioic, propanedioic, and ethanedioic acids, by cerium(IV) sulfate were studied by the spectrophotometric and pH-potentiometric methods with the aid of integral kinetic methods at an ionic strength I = 2 mol/L within the pH range of–0.3–1.6 in a sulfuric acid medium and at temperature of 293.15 K. The composition of these complexes, the form of organic ligand existence therein, the thermodynamic parameters of their formation, and the kinetic parameters of their intramolecular redox decomposition were determined. Linear correlations between the found thermodynamic and kinetic parameters of the examined complexes [CeOHL]+ were obtained. The rate equation of the redox process occurring in the systems Ce4+–H2L was established and the corresponding reaction model was considered.

Influence of premicelles and micellar aggregates of ionic and nonionic surfactants in the oxidative decarboxylation of l-lysine by gold(III) complexes

The influence of premicelles and micellar aggregates of the anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant Tween-20 in the oxidative decarboxylation of l-lysine by Au(III) complexes has been investigated spectrophotometrically at different temperatures in AcOH-NaOAc buffer medium (pH~3.72–4.98). Monopositive form of lysine (H2A)+ has been found to be kinetically active reductant while two different gold(III) complexes, namely, AuCl4− andAuCl3(OH)− are the predominant oxidant species. Gold(III) complexes receive a nucleophilic attack by the lysine to form a transient intermediate complex which subsequently experiences a two electron redox decomposition leading to gold(I) and iminium ion in the rate determining step. Iminium ion readily undergoes hydrolysis to produce 5-aminopentanal as the principal oxidation product. Before CMC, in case of Tween 20, the premicellar aggregates bring the reactants in close proximity through H-bonding and enhance the reaction rate. However, the premicellar aggregates of SDS with lysine restrict the entry of Au(III) species towards the amino acid reaction centre and decrease the rate sharply. The observed micellar effects on the reaction rate have been explained in terms of the association/solubilization of the reactant species into the Stern/palisade layer of the micellar pseudophase through electrostatic and H-bonding interactions. Lysine-micelle binding is moderated by the entropy change during the transfer of lysine from aqueous to micellar pseudophase and the enthalpy change for such transfer is determined by compensation between lysine-water, micelle-water and lysine-micelle interactions.

Photochemically Activated Motors: From Electrokinetic to Diffusion Motion Control.

Self-propelled micro/nanomotors that can transform chemical energy from the surrounding environment into mechanical motion are cutting edge nanotechnologies with potential applications in biomedicine and environmental remediation. These applications require full understanding of the propulsion mechanisms to improve the performance and controllability of the motors. In this work, we demonstrate that there are two competing chemomechanical mechanisms at semiconductor/metal (Si/Pt) micromotors in a pump configuration under visible light exposure. The first propulsion mechanism is driven by an electro-osmotic process stemmed from a photoactivation reaction mediated by H2O2, which takes place in two separated redox reactions at the Si and Pt interfaces. One reaction involves the oxidation of H2O2 at the silicon side, and the other the H2O2 reduction at the metal side. The second mechanism is not light responsive and is triggered by the redox decomposition of H2O2 exclusively at the Pt surface. We show that it is possible to enhance/suppress one mechanism over the other by tuning the surface roughness of the micromotor metal. More specifically, the actuation mechanism can be switched from light-controlled electrokinetics to light-insensitive diffusio-osmosis by only increasing the metal surface roughness. The different actuation mechanisms yield strikingly different fluid flow velocities, electric fields, and light sensitivities. Consequently, these findings are very relevant and can have a remarkable impact on the design and optimization of photoactivated catalytic devices and, in general, on bimetallic or insulating-metallic motors.