Cl Atoms Research Articles

Pyridine-4-thiol as halogen-bond (HaB) acceptor: influence of the noncovalent interaction in its reactivity.

The study of pyridine-4-thiol as a halogen-bond (HaB) acceptor has allowed the isolation of its cocrystal with the HaB donor IC6F4I, namely, 1,2,4,5-tetrafluoro-3,6-diiodobenzene bis(pyridin-1-ium-4-ylsulfanide), C6F4I2·2C5H5NS (1), where the S atom is the HaB acceptor, while the pyridine position is blocked by the proton. Furthermore, the S atom acts a dual acceptor and also establishes an interaction with the pyridinium proton from an adjacent molecule. The presence of these interactions in 1 contributes to the stabilization of the zwitterionic form. This pre-organization seems to have an influence on the reactivity of the compound since when left in dichloromethane solution, an unusual activation of the C-Cl bond is observed that leads to the formation of the bis[(pyridin-1-ium-4-yl)sulfanyl]methane dication, while the Cl atoms are still present as chloride counter-ions, i.e. 4,4'-[methanediyldi(sulfanediyl)]dipyridinium dichloride, C11H12N2S22+·2Cl- (2). In the crystal structure of 2 it is observed that the S atom is now acting as the donor part of a chalcogenide bond with the chloride anions.

Removable Pressure-Sensitive Adhesives Based on Acrylic Telomer Syrups

Removable pressure-sensitive adhesives (PSAs) are used in the production of self-adhesive materials such as protective films, masking tapes or biomedical electrodes. This work presents a new and environmentally friendly method of obtaining this type of adhesive materials, i.e., photochemically induced free radical telomerization. Adhesive binders to removable PSAs, i.e., the photoreactive acrylic telomer syrups (ATS) were prepared from n-butyl acrylate, acrylic acid, and 4-acrylooxybenzophenone. Tetrabromomethane (CBr4) or bromotrichloromethane (CBrCl3) were used as the telogens. ATS was modified with unsaturated polybutadiene resin and a radical photoinitiator. Adhesive compositions were coated onto a carrier and UV cross-linked. The effects of the chemical nature of telomers (i.e., terminal Br or Cl atoms) and their molecular weight (K-value), as well as the cross-linking degree on adhesive properties of PSAs, were studied. It was found that with the increase in telogen content in the system, the dynamic viscosity of ATS and K-value of acrylic telomers decrease, and the conversion of monomers increases. CBr4 turned out to be a more effective chain transfer agent than CBrCl3. Moreover, telomers with terminal Br-atoms (7.5 mmol of CBr4), due to slightly lower molecular weights and viscosity, showed a higher photocrosslinking ability (which was confirmed by high cohesion results at 20 and 70 °C, i.e., >72 h). Generally, higher values of the temperature at which adhesive failure occurred were noted for PSAs based on ATS with lower telogen content (7.5 mmol), both CBr4 and CBrCl3. The excellent result for removable PSA was obtained in the case of telomer syrup Br-7.5 crosslinked with a 5 J/cm2 dose of UV-radiation (adhesion ca.1.3 N/25 mm, and cohesion > 72 h).

Enhancing oxidation ability of graphitic carbon nitride photocatalysts to promote lignin Cα–Cβ bond cleavage in micellar aqueous media

As the most abundant aromatic resource, lignin is an appreciated biomass material to obtain aromatic high-value chemicals. However, the selective cleavage of lignin Cα–Cβ bonds under mild conditions constitutes a challenge. Herein, a photocatalyst having high oxidation capacity was successfully synthesized by codoping S and Cl atoms into graphite carbon nitride (g-C3N4). The resulting S,Cl/CN-1.5 photocatalyst exhibits enhanced photogenerated electron–hole separation ability and higher valence band potential than g-C3N4. S,Cl/CN-1.5 can efficiently break lignin Cα–Cβ bonds in micellar aqueous medium to produce benzaldehyde and benzyl alcohol as the main products. Mechanism studies show that the photocatalytic cleavage of lignin Cα–Cβ bonds proceeds via single-electron transfer and Cβ radical mechanisms in which hydroxyl radicals and photogenerated holes play an important role. Isotopic experiments show that the O atoms required for the photocatalytic cleavage of lignin Cα–Cβ bonds come from water in the micellar aqueous medium based on the full contact between water and substrate. Although O2 atmosphere is beneficial for the photocatalytic efficiency, O2 is not necessary for the photocatalytic cleavage of lignin Cα–Cβ bonds. This research provides a useful guide for designing efficient photocatalysts to depolymerize lignin into high-value chemicals.

Computational design of the novel building blocks for the metal-organic frameworks based on the organic ligand protected Cu4 cluster

Abstract Metal-organic frameworks (MOFs) are tunable porous network compounds composed of inorganic nodes bound by various organic linkers. Here we report the density functional theory (DFT) study of the MOF novel building blocks made of the Cu4 clusters protected by four organic ligands having two phenyl rings and terminated either with Cl or Br atom (precursors 1 and 2, respectively). The research was performed both in the gas phase and with the implicit effects of acetonitrile included, with two functionals, B3LYP and PBE, both with and without the second-order dispersion correction. We analyzed the structural features of the precursors 1 and 2, their electronic structures, molecular electrostatic potential (MEP) distribution, and global reactivity parameters (GRPs). Both functionals resulted in the singlets of the precursors 1 and 2 as the most stable species. The precursor structures optimized with the hybrid functional were found to be quite similar for both halogens, both containing somewhat distorted from planarity Cu4 cluster, with the outer phenyls of the ligands rotated relative to the inner phenyls. With both halogens and both DFT approaches, the frontier molecular orbitals (FMOs) of the precursors 1 and 2 were shown to have quite similar compositions. The change of the substituent from Br to Cl was found to cause slight stabilizations or destabilizations of the HOMOs and LUMOs. The central parts and especially the inner phenyl ring parts of the precursors 1 and 2 were suggested to play a role of nucleophile in various chemical reactions due to the significant accumulation of negative electrostatic potential. Also, weak intermolecular interactions might exist between the ligands of neighboring precursor molecules. Finally, with both substituents the precursors 1 and 2 should be relatively unreactive and demonstrate thermodynamic stability. Further, the precursors 1 and 2 should be quite stable in oxidation reactions and more active in reduction processes. Generally, the substituent nature was shown not to affect significantly the reactivity of the precursors 1 and 2, as well as their other properties.

Enhanced Photocatalytic H2 Evolution Performance of the Type-II FeTPPCl/Porous g-C3N4 Heterojunction: Experimental and Density Functional Theory Studies.

It is of great significance to improve the photocatalytic performance of g-C3N4 by promoting its surface-active sites and engineering more suitable and stable redox couples. Herein, first of all, we fabricated porous g-C3N4 (PCN) via the sulfuric acid-assisted chemical exfoliation method. Then, we modified the porous g-C3N4 with iron(III) meso-tetraphenylporphine chloride (FeTPPCl) porphyrin via the wet-chemical method. The as-fabricated FeTPPCl-PCN composite revealed exceptional performance for photocatalytic water reduction by evolving 253.36 and 8301 μmol g-1 of H2 after visible and UV-visible irradiation for 4 h, respectively. The performance of the FeTPPCl-PCN composite is ∼2.45 and 4.75-fold improved compared to that of the pristine PCN photocatalyst under the same experimental conditions. The calculated quantum efficiencies of the FeTPPCl-PCN composite for H2 evolution at 365 and 420 nm wavelengths are 4.81 and 2.68%, respectively. This exceptional H2 evolution performance is because of improved surface-active sites due to porous architecture and remarkably improved charge carrier separation via the well-aligned type-II band heterostructure. Besides, we also reported the correct theoretical model of our catalyst through density functional theory (DFT) simulations. It is found that the hydrogen evolution reaction (HER) activity of FeTPPCl-PCN arises from the electron transfer from PCN via Cl atom(s) to Fe of the FeTPPCl, which forms a strong electrostatic interaction, leading to a decreased local work function on the surface of the catalyst. We suggest that the resultant composite would be a perfect model for the design and fabrication of high-efficiency heterostructure photocatalysts for energy applications.

The calcium oxidotellurates Ca2(TeIVTeVIO7), Ca2(TeIVO3)Cl2 and Ca5(TeIVO3)4Cl2 obtained from salt melts

Abstract The mixed-valent calcium oxidotellurate(IV,VI) Ca2(Te2O7) (= Ca2(TeIVTeVIO7)) and the two calcium oxidotellurate(IV) dichlorides Ca2(TeIVO3)Cl2 and Ca5(TeIVO3)4Cl2 were obtained from metal chloride salt melts. Structure determination from single crystal X-ray data revealed a unique crystal structure in each case. A common motif in the three crystal structures is the formation of a framework perforated by channels into which the stereochemically active 5s 2 electron lone pairs E of the TeIV atoms are directed. Ca2(Te2O7) belongs to category I of the Robin-Day classification of mixed-valent compounds. Its crystal structure features a double chain of condensed trigonal-pyramidal [TeIVO3] and octahedral [TeVIO6] units embedded within a framework of [CaO x ] polyhedra (x = 7–8). The Cl atoms in the crystal structures of Ca2(TeIVO3)Cl2 and Ca5(TeIVO3)4Cl2 act as spacers between isolated trigonal-pyramidal [TeO3] units and exhibit weak interactions with the 5s 2 electron lone pairs E, with Cl⋯E distances <3.6 Å.

Regioselective Multisite Atomic-Chlorine Passivation Enables Efficient and Stable Perovskite Solar Cells.

Passivating defects using organic halide salts, especially chlorides, is an effective method to improve power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) arising from the stronger Pb-Cl bonding than Pb-I and Pb-Br bonding. However, Cl- anions with a small radius are prone to incorporation into the perovskite lattice that distorts the lead halide octahedron, degrading the photovoltaic performance. Here, we substitute atomic-Cl-containing organic molecules for widely used ionic-Cl salts, which not only retain the efficient passivation by Cl but also prevent the incorporation of Cl into the bulk lattice, benefiting from the strong covalent bonding between Cl atoms and organic frameworks. We find that only when the distance of Cl atoms in single molecules matches well with the distance of halide ions in perovskites can such a configuration maximize the defect passivation. We thereby optimize the molecular configuration to enable multiple Cl atoms in an optimal spatial position to maximize their binding with surface defects. The resulting PSCs achieve a certified PCE of 25.02%, among the highest PCEs for PSCs, and retain 90% of their initial PCE after 500 h of continuous operation.

DFT and Molecular Docking Analysis of Newly Synthesized Compound (2E)-3-[3-(Benzyloxy) Phenyl]-1-(4’-Chlorophe-Nyl)- 2-Propen-1-One [Bpclpo

Background: The parent molecule in the skeleton of this chalcone is the benzyloxy phenyl, which is linked to the chlorophenylpropen at C-3. The hydrophobic phenyl groups are naturally resistant to oxidation and reduction. Antiviral, antimalarial, antibacterial, anti-inflammatory, anticancer, antioxidant, antitubercular, and anti-Alzheimer activities are among the many pharmacological properties of chalcone derivatives. As a result, chalcone-based compounds are investigated using molecular docking and molecular modelling calculations to determine their suitability for drug formulation. Aims: To synthesise (2E)-3-[3-(benzyloxy) phenyl]-1-(4’-chlorophenyl)-2-propen-1-one [BPClPO] and perform DFT and molecular docking analysis of the synthesized compound to better understand its medicinal properties. Objective: The characterization of BPClPO is investigated in this study using various approaches, including wavefunction analysis and spectral analysis, which are associated with quantum chemical calculations to investigate its medicinal properties. Methods: The Gaussian 09W programme was used to perform computational chemistry calculations. The BPClPO's molecular structure was optimised, and the vibrational frequencies, Natural Bond Orbital (NBO), Fukui function, electronic properties and Nuclear Magnetic Resonance (NMR) chemical shifts were calculated using the B3LYP/6-311G (d, p) as the basis set. The VMD user interface and Multiwfn (3.4.1) software were used to conduct topological analyses of the Electron Localization Function (ELF), Localized Orbital Locator (LOL) and Reduced Density Gradient (RDG). The binding sites of active cancer proteins were calculated using the auto dock and auto grid. Results: Theoretical reaction path investigation was done for BPClPO to detect reactions from the parent chemical to the synthesized compound. Theoretical bond lengths and bond angles are compared with XRD values. Theoretical values of vibrations caused by electron-rich and electrondeficient centres were investigated. The electronic spectra of λmax were examined under UV-Vis light and the electron absorbance spectrum was absorbance wavelength and oscillator strength compared to theoretical values. The electron-rich carbon atoms are de-shielded in NMR, resulting in stronger fields and chemical shifts. The Harmonic Oscillator Model of Aromaticity (HOMA)and the retain ability of aromaticity in the addition and removal of electrons are examined in the Nucleus Independent Chemical Shift (NICS) study. The stability of the compound was investigated using Thermo- Gravimetric analysis and Differential Scanning Calorimeter (TG/DSC) analysis. Four cancer proteins with the reactive site were studied in docking simulations. Conclusions: The NBO analysis determined the intramolecular charge transfer within the molecule of high stabilization transition from C34-C37 donor to C35-C39 acceptor of (22.31 Kcal/mol) (π→π*) due to phenyl transition belonging to Cl atom in the ring. In the solvent phase, UV-visible spectra reveal a prominent peak at 300 λmax, with an absorbance range of intensity of 0.6983. (a.u.). According to TG/DSC experiments, the molecule begins to break around 290-370°C, and total decomposition occurs at 300°C. The molecule was found to have a higher bioactivity than and was employed related more to medicinal properties mechanism(s) of action in drug docking investigations.

Reaction mechanism and kinetics of H and Cl atom abstraction in Dichloromethane with OH radical

Dichloromethane or methylene chloride (DCM, CH2Cl2) is a hazardous toxic pollutant that enters the stratosphere via reaction with OH radicals. The present study examines DCM's complete reaction mechanism with OH radicals via H and Cl atom abstraction using density functional theory (DFT) methods such as B3LYP, M06-2X level of theory with 6–311++G(d,p) and 6–311++G(3df,2p) basis sets. In addition to DFT results, ab initio and composite methods such as MP2, CCSD(T), G3B3, and CBS-QB3 level of theory are utilized to validate the results. The subsequent secondary reaction mechanism of peroxy radicals with HO2 and NO radicals was studied in both singlet and triplet states. H-atom abstraction is the most favorable with a small relative energy barrier of 2.70 kcal/mol. The rate constant calculated by canonical variational transition state theory with the small curvature tunneling method (CVT/SCT) at 298 K is 9.50 × 10-13 cm3 molecule-1 s−1, which agrees well with previous experimental studies, and the atmospheric lifetime of the reaction is 12.18 days at 298 K. Possible new intermediates and products, such as dichloromethyl peroxide, dichloromethyl nitrate, and formyl chloride, have been identified.

Crystal structures of di-μ-chlorido-bis-({(E)-5-(ethyl-amino)-4-methyl-2-[(pyridin-2-yl)diazen-yl]phen-o-lato}copper(II)) and chlorido-bis-(1,10-phen-anthroline)copper(II) chloride tetra-hydrate.

The dark-red title complex crystallized from an equimolar methanol solution of (E)-5-(ethyl-amino)-4-methyl-2-[(pyridin-2-yl)diazen-yl]phenol and CuCl2(phen) (phen = 1,10-phenanthroline) as a centrosymmetric dimer, [CuCl(C14H15N4O)]2. The Cu atoms are bridged by two Cl ligands and have a slightly distorted square-pyramidal coordination, where two N atoms from the azo and the pyridine moieties, a phenolic O and a Cl atom comprise the base and the other Cl occupies the apex position. The apical Cu-Cl bond, 2.6192 (4) Å, is longer than the basal one, 2.2985 (3) Å, due to Jahn-Teller distortion. The dimers are associated via weak inter-molecular hydrogen bonds and π-π stacking inter-actions between phenyl and pyridine rings. A monomeric by-product of the same reaction, [CuCl(phen)2]Cl·4H2O, has a trigonal-bipyramidal coordination of Cu with equatorial Cl ligand, and extensive outer-sphere disorder. In the structure of 4, the packing of cations leaves continuous channels containing disordered Cl- anions and solvent mol-ecules. The identity of the solvent (water or a water/methanol mixture) was not certain. The disordered anion/solvent regions comprise 28% of the unit-cell volume. The disorder was approximated by five partly occupied positions of the Cl- anion and ten positions of O atoms with a total occupancy of 3, giving a total of 48 electrons per asymmetric unit, in agreement with the integral electron density of 47.8 electrons in the disordered region, as was estimated using the BYPASS-type solvent-masking program [van der Sluis & Spek (1990). Acta Cryst. A46, 194-201].

Tuning Molecular Electron Affinities against Atomic Electronegativities by Spatial Expansion of a π-System.

2,1,3-Benzochalcogenadiazoles C6 R4 N2 E (E/R; E=S, Se, Te; R=H, F, Cl, Br, I) and C6 H2 R2 N2 E (E/R'; E=S, Se, Te; R=Br, I) are 10π-electron hetarenes. By CV/EPR measurements, DFT calculations, and QTAIM and ELI-D analyses, it is shown that their molecular electron affinities (EAs) increase with decreasing Allen electronegativities and electron affinities of the E and non-hydrogen R (except Cl) atoms. DFT calculations for E/R+e⋅- →[E/R]⋅- electron capture reveal negative ΔG values numerically increasing with increasing atomic numbers of the E and R atoms; positive ΔS has a minor influence. It is suggested that the EA increase is caused by more effective charge/spin delocalization in the radical anions of heavier derivatives due to contributions from diffuse (a real-space expanded) p-AOs of the heavier E and R atoms; and that this counterintuitive effect might be of the general character.

Double-perovskite van der Waals heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo, W) as great potential material in photovoltaic devices

With the development of the material performance requirements of solar photovoltaic device design, heterostructure engineering has been widely studied as an effective method to improve the photoelectric properties of semiconductor materials. However, double perovskite-based van der Waals (vdW) heterostructure is still rare. Here, we formed twelve heterostructure constituted by two-dimensional transition metal-sulfur compounds XS2 (X=Cr, Mo, W) and the CsCl, NaInCl, CsNaInCl, Cl interface of inorganic double perovskite Cs2NaInCl6. By calculating the structure optimization and the surface binding energy based on the density functional theory (DFT), we obtained nine stable vdW heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo, W) with the CsCl, NaInCl, CsNaInCl interface. The electronic properties of heterostructure show that six vdW heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo, W) with CsCl, NaInCl interface are semiconductor heterostructure, among which the heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo) with NaInCl interface and Cs2NaInCl6-WS2 with CsCl interface are type I heterostructure, while the heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo) with CsCl interface and Cs2NaInCl6-WS2 with NaInCl interfaceare are type II heterostructure. The projected density of states of Cs2NaInCl6-XS2(X=Cr, Mo, W) heterostructures show that the VBM, CBM of Cs2NaInCl6 in Cs2NaInCl6-XS2 (X=Cr,Mo) with CsCl interface come from Cs, Cl atoms, respectively and the VBM, CBM of Cs2NaInCl6 in Cs2NaInCl6-WS2 with CsCl interface come from Cl, In atoms, respectively which consistent with the distribution pattern of type I, II heterostructure. The results of light absorption indicate that XS2 broadens the absorption spectrum of Cs2NaInCl6-XS2 heterostructures, enhancing their light absorption capacity. Therefore, the heterostructure Cs2NaInCl6-XS2 (X=Cr, Mo) with CsCl interface and Cs2NaInCl6-XS2 (X=W) with NaInCl interfaceare will be a promising material that can be applied in photovoltaic devices.

Synthesis, crystal structure, DFT studies and catalytic activity of an N-(2,2-dimethyl-1,3-dioxolane-4yl-methyl)benzimidazole ruthenium(II) hydrate complex

In this study, the new N-coordinated benzimidazole ruthenium(II) complex was synthesized. The complex was fully characterized by FT-IR, 1H and 13C NMR spectroscopic methods. The molecular structure of the complex has been verified by X-ray crystallography. Besides, theoretical structure and spectroscopic data were obtained using density functional theory (DFT/HSEH1PBE) method with the cc-pVDZ basis set for C, H, N, O and Cl atoms, and the LANL2DZ basis set for the metal atom, and compared with the experimental data. This complex has also been tested for the N-alkylation of aromatic amines with arylmethyl alcohols under neat conditions in the presence of KOBut.

State-to-State Dynamics in Mode-Specific Reactions of Cl + CH3D(v1-I, v1-II, and v4 = 1; |10⟩): Loss of Memory or Not

Several decades of the study of reaction dynamics culminate in the concept of mode specificity and bond selectivity in polyatomic systems. Until very recently, the main concern of those studies has been total reactivity and little attention has been paid to the mode-specific effects on the more detailed product-state and angular distributions. Conventional wisdom would anticipate that the fine detail should reveal a more pronounced mode dependency. However, a few recent studies showed that the product distributions could appear to be surprisingly insensitive to the modes of internal excitation of reagents. This counterintuitive finding led to a concept of loss of memory. Here, we present detailed experimental results in the reactions of the Cl atom with three distinct stretching-excited CH3D(vCH3 = 1) reagents. In conjunction with the previous reports on various aspects of this reaction, such a comprehensive set of data enables us to perform an in-depth examination of the validity of this new concept.

Selective dechlorination degradation of chlorobenzenes by dual single-atomic Fe/Ni catalyst with M-N/M-O active sites synergistic

Removal and detoxification of chlorobenzenes have attracted public concern, multiple active sites single-atom Fe and single-atom Ni composite nitrogen-doped graphene (FeSA/CN/NiSA) cathode catalyst supplied generation and adsorption capacity of hydrogen and hydroxyl active species. M-O active sites coupled with M-N improved activity and stability of the catalyst, and decreased bond breaking energy barrier of C-Cl, FeSA/CN/NiSA-NiF cathode showed superior removal performance of chlorinated aromatic hydrocarbons (monochlorobenzene: 98.9%, dichlorobenzene: over 90.4%, trichlorobenzene: over 85.7%) and selectivity. Chlorobenzenes were dechlorinated under low stepwise voltage on the FeSA/CN/NiSA-NiF cathode. The efficiencies of stepwise dechlorination reactions of chlorobenzenes were all above 76%, Faradaic efficiencies were above 71.8%. The FeSA/CN/NiSA-NiF cathode was not sensitive to the molecular structure and has overcome the high energy barrier of chlorobenzenes molecular structure. The electrophilic attack of H*ads formed hyperconjugation bond weakened the possibility of the Cl atom forming a bond with the benzene ring, and was favorable for the Cl position to achieve single-electron transfer dechlorination. The selective stepwise dechlorination degradation of chlorobenzenes by FeSA/CN/NiSA-NiF cathode with multiple active sites demonstrated the advantaged performance of M-O and M-N active sites coupled synergistic in electrochemical reduction and degradation, providing a strategy for product-selective degradation of chlorinated aromatic hydrocarbons.

Significantly activated persulfate by novel carbon quantum dots-modified N-BiOCl for complete degradation of bisphenol-A under visible light irradiation

The practical application of bismuth-based photocatalysts in the field of micropollutant photodegradation is limited due to their weak light absorption and rapid charge recombination. Herein, we have developed a novel carbon quantum dots-modified N-BiOCl (CDs-N-BiOCl) photocatalyst to activate persulfate (PS) for the complete elimination of endocrine-disruptor bisphenol A (BPA) under visible light irradiation. The photoelectric properties characterization shows that N atoms could replace Cl atoms or adsorb on Bi atoms to form local N 1s states in the BiOCl lattice, accompanied by the introduction of doping energy levels that shorten the electron migration distance. Meanwhile, the decorated CDs could effectively accept the photoinduced electrons from N-BiOCl conduction band to facilitate the charge separation. Thus, the 7%CDs-N-BiOCl (7CNB) nanocomposite synergistically activated PS realized rapid and effective degradation of BPA within 20 min (degradation efficiency and mineralization reached 100 % and 66.4 % respectively). Moreover, the 7CNB/PS system displayed favorable adaptability, durability, and interference resistance. Furthermore, the biotoxicity experiments demonstrated that the photodegradation intermediates promoted the growth of Escherichia coli which indicates its eco-friendliness for practical application. Finally, the electron transfer mechanism and the formation of reactive oxygen species in the photodegradation process were interpreted. In short, this work will present a promising strategy for bismuth-based photocatalysts to be used for the efficient treatment of real water bodies under visible light irradiation.

Computational high-throughput screening of layered double hydroxides as cathodes for chloride ion batteries

The chloride-ion battery (CIB) based on the anion transfer plays an essential role in developing new battery technologies. As a rare anion intercalated layered material, layered double hydroxide (LDHs) has attracted considerable attention as promising cathodes for CIBs. However, driven by the great compositional diversity, developing a general methodology to effective design and assess the usability of unexploited LDHs for CIBs is still a challenging issue. Herein, a computational high-throughput screening is performed among MII3MIII/IV LDHs (MII = Ni and Co; MIII/IV = Ni, Co, Fe, V, Cr and Ti). When designated as the only guest in LDHs gallery, Cl atoms tend to absorb above the O atoms without MIII/IV around and adsorption energy increases with the order of Ti > Cr > V > Fe > Co > undoped hydroxides. During the chlorination reaction, a special ClHOMIII/IV electron transfer chain is proposed for the first time. Furthermore, Cl storage performance for 11 cathodes were evacuated by the theoretical voltage in a full CIB system. The results indicates Ti-containing LDHs is the most encouraging cathodes, which is verified by the experimental measurement. This work provides a clear guidance and a theoretical insight into the anion insertion electrochemistry for LDHs materials.

Effect of Chlorine Substituents on the Photovoltaic Properties of Monocyanated Quinoxaline-Based D–A-Type Polymers

A string of monocyanated quinoxaline (Qx)-based D-A-type polymers systematically decorated with electron-attracting chlorine (Cl) atoms was created for use in non-fullerene polymer solar cells (PSCs). First, coupling of the benzodithiophene (BDT) donor and Qx acceptor with the strong electron-attracting cyano (CN) unit at its 5-position yielded the monocyanated reference polymer PB-CNQ. Subsequently, the additional Cl atoms were separately or simultaneously incorporated into the thiophene side groups of the BDT donor and Qx acceptor to create other objective polymers, PBCl-CNQ, PB-CNQCl, and PBCl-CNQCl. The Cl substituents on the BDT donor and Qx acceptor are represented by the names of the polymers. Owing to the favorable contributions of Cl substituents, the inverted-type non-fullerene PSCs based on partially chlorinated PBCl-CNQ (12.80%) and PB-CNQCl (13.93%) exhibited better power conversion efficiencies (PCEs) than the device based on unchlorinated reference PB-CNQ (11.19%). However, a significantly reduced PCE of 9.84% was observed for the device based on PBCl-CNQCl, in which Cl atoms were loaded on both the BDT donor and Qx acceptor at the same time. Hence, these results reveal that optimization of the number and position of Cl substituents in monocyanated Qx-based polymers is essential for enhancing their photovoltaic nature through the synergistic effects between two strong electron-attracting CN and Cl substituents.

Enhanced activity of CuOy/TNTs doped by CeOx for catalytic ozonation of 1,2-dichloroethane at normal temperatures: Performance and catalytic mechanism

Achieving efficient and stable catalysts with chlorine resistance is of great importance for chlorinated volatile organic compounds (CVOCs) degradation. This study developed catalysts containing abundant CeOCu bonds anchored on titanium nanotubes (TNTs) to form strong electronic metal–metal interaction (EMMI) coordination structure for efficiently catalytic ozonation of 1,2-dichloroethane (1,2-DCE). The occurrence of EMMI resulted in the formation of electron-poor/rich centers and a high proportion of weak-acidity sites over Ce-Cu/TNTs catalysts. Among various catalysts, 1Ce1Cu/TNTs exhibited the optimum catalytic performance with 92.5 % of 1,2-DCE conversion and 85.4 % of CO2 selectivity, the long-term stability of 24 h and the good water resistance to 50 % relative humidity (RH). Importantly, the XPS results and DFT calculations suggested Ce drove the Cl atom off Cu species, thus alleviating the chloridion deposit on Cu sites, accelerating the migration of chlorine and offering more redox sites for O3 activation. Electron paramagnetic resonance (EPR) and radical quenching tests identified that •OH was a key reactive oxygen species to achieve efficient degradation of 1,2-DCE. The possible reaction pathways for the catalytic ozonation of 1,2-DCE included three parts, including O3 activation, 1,2-DCE preliminary degradation and deep oxidation, which obeyed the L-H mechanism.

Development and validation of a new in situ technique to measure total gaseous chlorine in air

Abstract. Total gaseous chlorine (TClg) measurements can improve our understanding of unknown sources of Cl in the atmosphere. Existing techniques for measuring TClg have been limited to offline analysis of extracted filters and do not provide suitable temporal information on fast atmospheric processes. We describe high-time-resolution in situ measurements of TClg by thermolyzing air over a heated platinum (Pt) substrate coupled to a cavity ring-down spectrometer (CRDS). The method relies on the complete decomposition of TClg to release Cl atoms that react to form HCl, for which detection by CRDS has previously been shown to be fast and reliable. The method was validated using custom organochlorine permeation devices (PDs) that generated gas-phase dichloromethane (DCM), 1-chlorobutane (CB), and 1,3-dichloropropene (DCP). The optimal conversion temperature and residence time through the high-temperature furnace was 825 ∘C and 1.5 s, respectively. Complete conversion was observed for six organochlorine compounds, including alkyl, allyl, and aryl C–Cl bonds, which are amongst the strongest Cl-containing bonds. The quantitative conversion of these strong C–Cl bonds suggests complete conversion of similar or weaker bonds that characterize all other TClg. We applied this technique to both outdoor and indoor environments and found reasonable agreements in ambient background mixing ratios with the sum of expected HCl from known long-lived Cl species. We measured the converted TClg in an indoor environment during cleaning activities and observed varying levels of TClg comparable to previous studies. The method validated here is capable of measuring in situ TClg and has a broad range of potential applications.