Addition Of ClO4 Research Articles

Tri-anion solvation structure electrolyte improves the electrochemical performance of Li||LiNi0.8Co0.1Mn0.1O2 batteries.

Li||LiNi0.8Co0.1Mn0.1O2 batteries,which consist of lithiummetal anode (LMA) matchedwith NCM811 cathode, have an energy density more than twice that of lithium ion battery (LIB).However, the unstable electrode/electrolyte interface still hinders its practical application.Ether electrolytes show promise in improving the stability of LMA and NCM811 cathodes.However, a robust and stableelectrode/electrolyte interface in Li||NCM811 batteries cannot be easily and efficiently achieved with most of the ether electrolytes reported in present studies. Herein, we present a straightforwardand efficient tri-anion synergistic strategy to overcome this bottleneck. The addition of ClO4- and NO3- anions to LiFSI-based ether electrolytes forms a unique solvation structure with tri-anion (FSI-/ClO4-/NO3-) participation(LB511).This structure not only enhances the electrochemical window of the ether electrolytes but also achieves a stable Li||NCM811batteries interface.The interaction between electrode and electrolyte is suppressed andan inorganic-rich (LiF/Li3N/LiCl) SEI/CEI layer is formed. Meanwhile, the coordination structure in the LB511 electrolyte increases the overpotential for Li deposition, resulting in a uniform and dense layer of deposition.Therefore,the Li||Cu cells using the LB511 electrolytehave an average CE of 99.6%.TheLi||NCM811 batteries was cycled stably for 250 cycles with a capacity retention of 81% in the LB511 electrolyte (N/P = 2.5, 0.5 C).

N‐Confused Porphyrin – A Unique “Turn‐On” Chemosensor for CN− and F− ions and “Turn‐Off” Sensor for ClO4− ions

N-Confused meso-tetrakis(4-carbomethoxyphenyl)porphyrin (1) and its Ni(II) complex (1 a) have been synthesized and utilized for anion sensing studies, and the results are compared with N-confused meso-tetraphenylporphyrin (NCTPP). Anion susceptibilities of 1 and 1 a were investigated using spectroscopic, electrochemical, and DFT studies. Porphyrins 1 and 1 a were able to detect CN- , F- , and ClO4 - ions selectively over the tested set of anions even at ppm level. Interestingly, the addition of ClO4 - ions resulted in fluorescence quenching (turn off) whereas the addition of F- or CN- resulted in fluorescence enhancement (turn on). Notably, the TFA addition resulted in fluorescence quenching, whereas the fluorescence enhancement was observed while adding TBAOH. The higher association constant (Ka ) values with anions, lower detection limit, and shifts in redox potentials are due to the electron-withdrawing effect of the -COOCH3 group at the para-position of the meso-phenyl ring. This electron-withdrawing nature is crucial for the higher affinity towards anions. The anion sensing description in this article may not only unveil the built-in nature of N-confused porphyrins, but may also provide a general proposal for the development of novel anion sensors based on porphyrinoids. The electron-deficient porphyrin framework, large polarisable π-system, and anion binding through the outer NH or a combination of the above factors serve as a foundation for N-confused porphyrin to act as an anion sensor.

Co-reduction of nitrate and perchlorate in a pressurized hydrogenotrophic reactor with complete H2 utilization

A novel pressurized hydrogenotrophic reactor operating at high rates was recently developed specifically for the removal of nitrate (NO3−) from drinking water. The reactor is characterized by safe and economical operation since hydrogen (H2) purging intrinsic to conventional H2-based denitrifying systems is not required and H2 loss occurs only through the effluent, resulting in H2 utilization efficiency above 90%. In this research, a new treatment scheme to remove NO3− and perchlorate (ClO4−) combining the pressurized reactor with a following open-to-atmosphere polishing unit is presented. In the pressurized reactor, NO3− and ClO4− are simultaneously removed. In the polishing unit, the residual dissolved H2 from the pressurized reactor serves to further reduce ClO4− to trace concentrations below recommended levels.First, ClO4− reduction together with denitrification was demonstrated in the pressurized reactor without special inoculation and a maximal ClO4− volumetric removal rate of 1.83g/(Lreactor·d) was achieved. Microbial population analyses before and after the addition of ClO4− were similar with a large fraction of the genus Dechloromonas. Results show that the combined treatment scheme consisting of the pressurized reactor and the polishing unit allowed for the reduction of ClO4− concentration down to a minimal value of 2µg/L with a simultaneous increase of the H2 utilization efficiency from 95% up to almost 100%.

Varietal differences in the growth of rice seedlings exposed to perchlorate and their antioxidative defense mechanisms.

A hydroponic experiment was conducted to investigate perchlorate (ClO4 (-) ) phytotoxicity in different rice varieties. Considerable variations were observed when 24 rice varieties were treated with ClO4 (-) . The shoot height, root length, and biomass of most varieties were significantly reduced by ClO4 (-) . The roots were more sensitive than the shoots. Hierarchical clustering analysis demonstrated primarily 4 groups: ClO4 (-) -sensitive, medium ClO4 (-) -sensitive, medium ClO4 (-) tolerant, and ClO4 (-) -tolerant. Gannuoxiang (a ClO4 (-) -tolerant variety) and IR65598-112-2 (a ClO4 (-) -sensitive variety) were chosen to explore their antioxidant response when exposed to 0.2 mmol/L, 2.0 mmol/L, and 4.0 mmol/L ClO4 (-) . The results showed that the activities of superoxide dismutase and catalase increased in the shoots and roots of gannuoxiang with increasing doses of ClO4 (-) , but both of them decreased at higher concentrations of ClO4 (-) in IR65598-112-2. The addition of ClO4 (-) led to a significant increase in peroxidase activities for both of the varieties, whereas the increase was more pronounced in gannuoxiang than in IR65598-112-2. No significant difference was found in malondialdehyde (MDA) contents in gannuoxiang, whereas the addition of ClO4 (-) increased the MDA level significantly in IR65598-112-2. The results indicated that gannuoxiang has higher activities of antioxidant enzymes than IR65598-112-2 to cope with oxidative damage caused by ClO4 (-) stress, which may be the main cause of its high tolerance.

Lighting of a rhodamine-based fluorescent lamp using ClO4− as a connector: detection by the naked eye and cell imaging studies of trace amounts of ClO4− ions

A visible light excitable (λex = 520 nm), rhodamine-based, perchlorate selective ‘turn on’ fluorescent probe, RHENTU, is prepared and characterized by spectroscopic techniques. The probe is suitable for use in the detection of ClO4− by the naked eye. It is also capable of detecting ClO4− in contaminated living cells under a fluorescence microscope. Common anions viz. F−, Cl−, Br−, I−, N3−, NCO−, NO2−, NO3−, SCN−, CN−, CH3COO−, SO42− and H2PO4− do not interfere with these processes. The binding constant of RHENTU for ClO4− has been determined to be 2.9 × 103 M−1/2 using the Benesi–Hildebrand equation. Addition of ClO4− to RHENTU afforded an intense red emission with a quantum yield (4.5 × 10−2) five times greater than that of free RHENTU. The lowest detection limit (LOD) of RHENTU for ClO4− is 1 × 10−7 M.

Modeling C–H Abstraction Reactivity of Nonheme Fe(IV)O Oxidants with Alkanes: What Role Do Counter Ions Play?

It is shown that the addition of ClO4– counterions to [N4PyFeO]2+ enables us to avoid the anomalies associated with the self-interaction error in DFT and to describe for the first time the entire trajectories for alkane hydroxylation and desaturation by this potent oxidant. The predicted reactivity trends for cyclohexadiene and cyclohexane reproduce the experimentally observed product selectivity and relative ease of oxidation. Furthermore, the advent of this well-behaved oxidant enables us to derive generalizing principles: (a) orbital selection rules that predict transition state structures and (b) the exchange-enhanced reactivity (EER) principle that predicts the dominance of the high-spin state during the entire oxidation process. It is shown that the orbital selection rules and EER principle are general descriptors of the reactivity of metal-oxo systems and appear to be fundamental principles of chemistry.

Electrolyte-Induced Phase Separation and Charge Reversal of Cationic Zwitterionic Micelles

The solution properties and anion recognition selectivity of the N-dodecyl-N,N,N',N',-tetramethyldiethylenediammonio-propane sulfonate bromide (DEPB) and N-dodecyl-N,N,N',N',-tetramethyl-1,3-propylenediammonio-propane sulfonate bromide (DPPB) micelles have been studied. These micelles have similar properties except for the phase behavior induced by coexistent anions. The addition of ClO4(-) or I(-) to aqueous DEPB causes phase separation, and further addition results in the dissolution of the separated phases. In contrast, no phase separation occurs for DPPB. Charge reversal of the micelles occurs during the addition of the anions. The difference in the phase behavior between DEPB and DPPB comes from the different sizes of the micelles; the addition of ClO4(-) allows the formation of large aggregates of DEP (~50 nm in diameter).

Photocatalytic Reduction and Recovery of Copper by Polyoxometalates

A series of polyoxometalates PW12O40(3-), SiW12O40(4-), and P2Mo18O62(6-) have been used as photocatalysts for recovery of copper and production of fine metal particles. The process involves absorption of light by polyoxometalates, oxidation of an organic substrate, for instance, propan-2-ol as sacrificial reducing reagent, and reoxidation of the reduced polyoxometalates by Cu2+ ions, closing the photocatalytic cycle. Copper(II) ions are reduced to copper(I) and finally to zero-state particles in a 2-electron process, as also suggested by the half-order dependence. Increase of catalyst or propan-2-ol concentration, or both, accelerates the photodeposition of copper until a saturation value is reached. The method is operational at a wide range of copper concentrations varying from 3 to 1300 ppm, leading to very low final concentrations (<0.2 ppm). The presence of dioxygen suppresses the initiation of copper recovery, though the process is equally effective after dioxygen is consumed. The process is independent of pH within the range 0.3-5.0. Addition of ClO4-, NO3-, or CH3COO- has no effect on the removal of copper ions. Chloride ions retard the enhancement of copper precipitation through stabilization of copper(I). This homogeneous, polyoxometalate-based process exhibits some benefits in comparison with the semiconductor-based (heterogeneous) recovery of metals: The final zero-state metal particles are obtained in pure form. No separation from the catalyst is needed, and moreover, the process is catalytic as the photodeposited metal particulates do not hinder the photocatalytic action of polyoxometalate anions.

A Quantitative Treatment of Dephosphorylation by an Amphiphilic Hydroxamate Ion. The Role of Micellar Charge

Comicelles of (Z)-dodecano-N-phenylhydroxamate ion (1b) with cationic and sulfobetaine surfactants effectively accelerate the hydrolysis of p-nitrophenyl diphenyl phosphate (pNPDPP). The surfactants are cetyl trimethyl- and tributylammonium bromide (CTABr and CTBABr respectively), and (tetradecyldimethylammonio)propanesulfonate (SB3-14). Reaction is slower in comicelles with Brij-35, 23-dodecyl ether (C12E23), and much slower in comicelles with sodium dodecyl sulfate (SDS). In all conditions, the hydroxamic acid was fully deprotonated and pNPDPP was fully micellar-bound and, on the basis of NMR data (Langmuir 1997, 13, 6439), it appears that the rate effects are due to differences in the relative locations of pNPDPP and the hydroxamate residue in the interfacial region, which are related to micellar charge. Inhibition of reaction in SB3-14 on addition of ClO4-, and acceleration in SDS by weakly hydrophilic cations, are understandable in these terms, as are effects of n-dodecyldimethylphosphine oxide and n...

Tetranuclear vanadium(III) carboxylate chemistry, and a new example of a metal butterfly complex exhibiting spin frustration: structure and properties of [V4O2(O2CEt)7(bpy)2](ClO4)

Treatment of [VCl3(thf)3](thf = tetrahydrofuran) with bpy (bpy = 2,2′-bipyridine) and NaO2CEt in a 1 : 1 : 3 molar ratio in Me2CO followed by addition of ClO4– allows isolation of [V4O2(O2CEt)7(bpy)2](ClO4)[4(ClO4)], which contains a butterfly-like V4 unit; variable-temperature magnetic susceptibility studies show 1 to possess both ferro- and antiferro-magnetic exchange interactions leading to spin-frustration effects and an S= 3 ground state.

Raman Spectral Studies of the Effects of Perchlorate Ion on Water Structure

Raman contours corresponding to the OD and OH stretching vibrations from HDO, as well as from H2O and D2O, were obtained at 25°C from a series of ternary aqueous solutions containing HDO, ClO4− (Li+, Na+, K+), and H2O or D2O. The Raman spectra were obtained photoelectrically using 4880-Å argon-ion-laser excitation, as well as conventional 4358-Å mercury excitation. Quantitative Raman data were obtained from ternary solutions having NaClO4 concentrations from 1 to 4M, and stoichiometric concentrations of 5.51M D2O (H2O as solvent), or 5.53M H2O (D2O as solvent). Raman spectra were also obtained from solutions having lower (and higher) HDO or NaClO4 concentrations. In addition, binary solutions of NaClO4 and H2O or D2O were examined. Addition of ClO4− to solutions containing HDO, and H2O or D2O produces a pronounced splitting of the OD and OH stretching contours from HDO, as well as from D2O and H2O. The splittings are directly observable in the Raman spectra. Two principal peaks or components, having frequencies nearly identical to components uncovered previously in the absence of ClO4−, result in the HDO case (or four major components in the D2O and H2O cases). The Raman intensities of the high-frequency OD or OH components from HDO (or of the corresponding high-frequency D2O or H2O components) increase relative to the low-frequency components with addition of ClO4−. The effects are evident even at 0.5M ClO4− and below. In addition, isosbestic frequencies are observed from the binary and ternary perchlorate solutions for bands of HDO, D2O, and H2O, and the values compare favorably with isosbestic frequencies obtained previously at a series of temperatures. Examination of the OD and OH stretching contours from HDO at high ClO4− concentration, at which the high-frequency components are nearly isolated, also indicates that the component shapes are Gaussian. The Raman data indicate that the ClO4− ion is a strong structure breaker, and that it does not hydrate appreciably, in agreement with the recent infrared absorbance results of Kecki et al. The data also provide clear evidence in contradiction to spectroscopic continuum models of water and aqeuous solutions, but mixture models involving several major classes of interactions, e.g., hydrogen-bonded or non-hydrogen-bonded OD or OH groups, and OD or OH groups engaged in the hydration of cationic and anionic species, but excluding ClO4−, are in accord with the data.