酚类污染物解离态与非解离态光解特性及其速率常数的预测

以氙灯为光源模拟太阳光,通过研究不同pH条件下3种酚类污染物直接光解的过程,探讨了酚类污染物的解离对其光解规律的影响,并建立了解离态与非解离态酚类污染物光解速率常数的计算方法及预测模式.结果表明,随着pH从4.0增加到9.0,五氯酚的光解速率常数随之从25.30×10-4min-1增加到82.90×10-4min-1,而对硝基酚的光解速率常数相应从11.90×10-4min-1降低到了3.18×10-4min-1.苯酚的光解趋势与对硝基酚相似,当pH从4.0增加到11.0时,其光解速率常数依次从32.50×10-4min-1降低至13.40×10-4min-1.3种酚类化合物的光解总速率常数与解离度之间均满足幂函数变化规律.任意解离度条件下的解离态和非解离态光解速率常数,可根据幂函数的切线方程来确定.解离对酚类物质降解规律的影响主要是通过氧负离子的形成,改变苯环以及其他取代基团的活性而造成的.该研究结果为进一步了解天然水环境中酚类污染物的环境行为提供了理论参考.

Data-Driven Viewpoint for Developing Next-Generation Mg-Ion Solid-State Electrolytes

Magnesium(Mg)is a promising alternative to lithium(Li)as an anode material in solid-state batteries due to its abundance and high theoretical volumetric capacity.However,the sluggish Mg-ion conduction in the lattice of solidstate electrolytes(SSEs)is one of the key challenges that hamper the development of Mg-ion solid-state batteries.Though various Mg-ion SSEs have been reported in recent years,key insights are hard to be derived from a single literature report.Besides,the structure-performance relationships of Mg-ion SSEs need to be further unraveled to provide a more precise design guideline for SSEs.In this viewpoint article,we analyze the structural characteristics of the Mg-based SSEs with high ionic conductivity reported in the last four decades based upon data mining-we provide big-data-derived insights into the challenges and opportunities in developing next-generation Mg-ion SSEs.

Synthesis of High Purity Lithium Sulfide for Sulfide Solid Electrolyte Applications through Hydrogen Reduction of Lithium Sulfate

This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction process has been successfully developed to synthesize well-crystallized and single-phase Li_(2)S powder by investigating the melting,sintering and reduction behavior of the mixtures of Li_(2)SO_(4)-Li_(2)S.High purity alumina was found to be the most suitable crucible material for producing high purity Li_(2)S,because it was not attacked by the Li_(2)SO_(4)-Li_(2)S melt during heating,as compared with other materials,such as carbon,mullite,quartz,boron nitride and stainless steel.The use of synthesized LizS resulted in higher purity and substantially higher room temperature ionic conductivity(2.77 mS·cm^(-1))for the argyrodite sulfide electrolyte Li_(6)PS_(5)Cl than commercial Li_(2)S(1.12 mS·cm^(-1)).This novel method offers a great opportunity to produce battery grade Li_(2)S for sulfide solid electrolyte applications.

乳酸对肌酸激酶活性抑制作用的研究

应用酶活测定的方法分析了肌酸激酶在不同浓度乳酸中的活性变化 .实验结果说明在失活过程中没有蛋白质的聚沉 ;肌酸激酶的失活遵循一级反应的一相过程 ;失活与乳酸浓度和作用时间呈正相关 .通过对比实验结果显示 ,乳酸是通过其解离状态的H+改变了机体pH值而影响肌酸激酶活性的 。

Low-Energy Electron Attachment to Serine Conformers： Shape Resonances and Dissociation Dynamics

Shape resonances of electron-molecule system formed in the low-energy electron attachment to four low-lying conformers of serine （serine 1, serine 2, serine 3, and serine 4） in gas phase are investigated using the quantum scattering method with the non-empirical model potentials in single-center expansion. In the attachment energy range of 0-10 eV, three shape resonances for serine 1, serine 2, and serine 4 and four shape resonances for serine 3 are predicted. The one-dimensional potential energy curves of the temporary negative ions of electron-serine are calculated to explore the correlations between the shape resonance and the bond cleavage. The bond-cleavage selectivity of the different resonant states for a certain conformer is demonstrated, and the recent experimental results about the dissociative electron attachment to serine are interpreted on the basis of present calculations.

Neutral Dissociation of Superexcited Nitric Oxide Induced by Intense Laser Fields

Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for the NO molecule upon interaction with 800 nm intense laser radiation of duration 60 fs and intensity 0.2 PW/cm^2. Intense laser pulse causes neutral dissociation of superexcited NO molecule by way of multiphoton excitation, which is equivalent to single photon excitation in the extreme-ultraviolet region by synchrotron radiation. Potential energy curves （PECs） are also built using the calculated superexcited state of NO^＋. In light of the PECs, direct dissociation and pre-dissociation mechanisms are proposed respectively for the neutral dissociation leading to excited fragments N^＊ and O^＊.

Laser Flash Photolysis Mechanism of Anthraquinone-2-Sodium Sulfonate in Pyridine Ionic Liquid/Water Mixed System

The photochemical reaction process of anthraquinone-2-sodium sulfonate （AQS） in the mixture of water （H2O） and N-butylpyridinium tetrafluoroborate （[BPy] [BF4]） was studied using the laser flash photolysis technique. Experimental results show that the excited triplet of AQS （3AQS＊） could react rapidly with H2O and the transient absorption spectra greatly changed by increasing the volume fraction of the ionic liquid （VIL） in [BPy][BF4]/H2O mixtures. The absorbance at 510 nm increased gradually with increasing VIL when 0〈VIL〈0.1. By contrast, the absorbance decreased gradually when VIL〉0.1. Otherwise, the absorbance of the band near 380 nm steadily increased. The apparent kinetic parameters of transient species B and ^3AQS＊ are obtained approximately. 3AQS＊ abstracting hydrogen from [BPy]＋ was also explored. It was deduced that the 350-420 nm band was the superposition of the peaks of 3AQS＊ and AQSH＇. The two reactions of 3AQS＊ with [BPy][BF4] and H2O are a pair of competitive reactions. We also concluded that the entire reaction processes slow down in the case of high [BPy] [BF4] concentrations.

Theoretical Investigation on Photoionization and Dissociative Photoionization of Toluene

The photoionization and dissociation photoionization of toluene have been studied using quantum chemistry methods. The geometries and frequencies of the reactants, transition states and products have been performed at B3LYP/6-311＋＋G（d,p） level, and single-point energy calculations for all the stationary points were carried out at DFT calculations of the optimized structures with the G3B3 level. The ionization energies of toluene and the ap- pearance energies for major fragment ions, C7H7＋, C6H5＋, C5H6＋, C5H5＋, are determined to be 8.90, 11.15 or 11.03, 12.72, 13.69, 16.28 eV, respectively, which are all in good agree- ment with published experimental data. With the help of available published experimental data and theoretical results, four dissociative photoionization channels have been proposed： CTHT＋＋H, C6Hs＋＋CH3, C5H6＋WC2H2, CsHs＋＋C2H2＋H. Transition structures and intermediates for those isomerization processes are determined in this work. Especially, the structures of C5H6＋ and C5H5＋ produced by dissociative photoionization of toluene have been defined as chain structure in this work with theoretical calculations.

Photodissociation of HOD via the C1B1 State： OD/OH Branching Ratio and OD Bond Dissociation Energy

Photodissociation of jet-cooled HOD via the C state around 124 nm has been studied using the H（D）-atom Rydberg tagging time-of-flight technique. Rotational state resolved action spectrum and the product translational energy distribution spectra have been recorded for both D＋OH and H＋OD dissociation channels. Product channel OH/OD branching ratios for the individual C-X rotational transition have been determined. A comparison is also given with the B-X and A-X transitions. In addition, the dissociation energy of the OD bond in HOD has been determined accurately to be 41751.3±5 cm-1.

Ion-Pair Photodissociation of Trichloromonofluoromethane

fragments, F- and Cl- including two isotope species 35Cl- and 37Cl-, are observed in the photoexcitations of CFC13. The ion-pair anion efficiency spectra of 35Cl- and 37Cl- are recorded in the photon energy range of 7.75-22.00 eV. The threshold of ion-pair dissociation CFCl3-CFC12＋＋Cl- is experimentally determined to be 7.944-0.04 eV. With the references of the high-resolution photoabsorption spectra reported in the literatures, we make tentative assignments of the electron valence-to-Rydberg transitions. Furthermore, the multibody ion-pair fragmentation processes to Cl- are discussed by comparison between the calculated thermochemical thresholds and the experimental efficiency spectrum.

Empirical decay relationship between ionic conductivity and porosity of garnet type inorganic solid-state electrolytes

Ionic conductivity is one of the crucial parameters for inorganic solid-state electrolytes.To explore the relationship between porosity and ionic conductivity,a series of Li_(6.4)Ga_(0.2)La_(3)Zr_(2)O_(12) garnet type solid-state electrolytes with different porosities were prepared via solid-state reaction.Based on the quantified data,an empirical decay relationship was summarized and discussed by means of mathematical model and dimensional analysis method.It suggests that open porosity causes ionic conductivity to decrease exponentially.The pre-exponential factor obeys the Arrhenius Law quite well with the activation energy of 0.23 eV,and the decay constant is averaged to be 2.62%.While the closed porosity causes ionic conductivity to decrease linearly.The slope and intercept of this linear pattern also obey the Arrhenius Law and the activation energies are 0.24 and 0.27 eV,respectively.Moreover,the total porosity is linearly dependent on the open porosity,and different sintering conditions will lead to different linear patterns with different slopes and intercepts.

Theoretical Study of Isoprene Dissociative Photoionization

Theoretical calculations have been carried out to investigate the possible dissociation channels of isoprene. We focus on the major fragment ions of C5H7＋, C5H5＋, C4H5＋, C3H6＋, C3H5＋, C3H4＋, C3H3＋ and C2H3＋, which were observed experimentally from the isoprene dissociative photoionization. The energy calculations were performed with the CBS-QB3 model. All the geometries and energies of the fragments, intermediates and transition states involved in the dissociations channels were determined. Finally, the mechanisms of the dissociation pathways were discussed on the comparison of theoretical and experimental results.

Ion-Pair Dissociations of Br CN by Electron Impacts

Ion-pair dissociation is an important molecular process and frequently happens when the target molecule is pumped to its electronically superexcited states. In contrast to the experimental studies of photoexcitation ion-pair dissociation, there are some experimental challenges in the electron-impact ion-pair dissociation study, in particular, on determination of the energetic threshold. Here we report an experimental development for the ion-pair dissociation study by using the monochromized electron impacts. As an example, the threshold of BrCN→Br^-+CN^+ is determined as 13.78 eV according to the appearance energy of CN^+ signals, meanwhile, the time-sliced ion velocity image of CN^+ is recorded at 16.09 eV and indicates an anisotropic distribution of the CN^+ momentum.

Two-Photon Dissociation Dynamics of Hydroxyl Radical

Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.

Mg2＋-ion Conducting Polymer Electrolytes： Materials Characterization and All-Solid-State Battery Performance Studies

For All-Solid-State battery applications, Mg2＋-ion conducting polymer electrolytes and Mg-metal electrode are currently considered as alternate choices in place of Li＋-ion conducting polymer electrolytes/Li-metal electrode. Present paper reports fabrication of All-Solid-State battery based on the following Mg2＋-ion conducting nano composite polymer electrolyte （NCPE） films： [85PEO： 15Mg（C104）2] ＋ 5% TiO2 （〈 100 nm）, [85PEO： 15Mg（CIO4）2] ＋ 3% SiO2（-8 nm）. [85PEO： 15Mg（CIO4）2] ＋ 3% MgO （〈 100 nm）, [85PEO：15Mg（C1O4）2] ＋ 3% MgO （-44 μm）. NCPE films were prepared by hot-press technique. Solid Polymer Electrolyte （SPE） composition： [85PEO： 15Mg（CIO4）2], identified as high conducting film at room temperature, has been used as ISt--phase host and nano/micro particles of active （MgO）/passive （SiO2, TiO2） fillers as IInd-phase dispersoid. Filler particle dependent conductivity studies identified above mentioned NCPE films as optimum conducting composition （OCC） at room temperature. Ion transport behavior of SPE/NCPE film materials was investigated previously. Present paper reports materials characterization and cell performance studies on All-Solid-State batteries： Mg （Anode） Ⅱ SPE or NCPE films tt C＋MnO2＋Electrolyte （Cathode）. Open circuit voltage （OCV） obtained was in the range： 1.79-1.92 V. The batteries were discharged at room temperature under different load conditions and some important battery parameters have been evaluated from plateau region of cell-potential discharge profiles. All the batteries performed quite satisfactorily specially under low current drain states.

A strong Lewis acid imparts high ionic conductivity and interfacial stability to polymer composite electrolytes towards all-solid-state Li-metal batteries

The development of high-performance solid polymer electrolytes is crucial for producing all-solid-state lithium metal batteries with high safety and high energy density.However,the low ionic conductivity of solid polymer electrolytes and their unstable electrolyte/electrode interfaces have hindered their widespread utilization.To address these critical challenges,a strong Lewis acid(aluminum fluoride(AIF_(3)))with dual functionality is introduced into poly(ethylene oxide)(PEO)-based polymer electrolyte.The AlF;facilitates the dissociation of lithium salt,increasing the iontransfer efficiency due to the Lewis acid-base interaction;further the in-situ formation of lithium fluoride-rich interfacial layer is promoted,which suppresses the uneven lithium deposition and continuous undesired reactions between the Li metal and PEO matrix.Benefiting from our rational design,the symmetric Li/Li battery with the modified electrolyte exhibits much longer cycling stability(over 3600 h)than that of the pure PEO/lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)electrolyte(550 h).Furthermore,the all-solid-state LiFeP04 full cell with the composite electrolyte displays a much higher Coulombic efficiency(98.4%after 150 cycles)than that of the electrolyte without the AlF;additive(63.3%after 150 cycles)at a large voltage window of 2.4-4.2 V,demonstrating the improved interface and cycling stability of solid polymer lithium metal batteries.

Unlocking solid-state conversion batteries reinforced by hierarchical microsphere stacked polymer electrolyte

Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode-electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF_(3) conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This gC_(3)N_(4) stuffed polyethylene oxide(PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional(2 D)-nanosheet-built porous g-C_(3)N_(4) as three-dimensional(3 D) textured filler can strongly cross-link with PEO matrix and Li TFSI(TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity(2.5×10^(-4) S/cm at 60℃) and Li+transference number(0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO_(4) solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF_(3) cells show highly stabilized capacity as high as 300 m Ah/g even after 200 cycles and of 200 m Ah/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution(>55%) and diffusion coefficient(as high as10^(-12) cm^(2)/s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true "all-solid-state" due to the indispensable step of polysulfide solid-liquid conversion.

Modulating composite polymer electrolyte by lithium closo-borohydride achieves highly stable solid-state battery at 25℃

Rational composite design is highly important for the development of high-performance composite polymer electrolytes(CPEs)for solid-state lithium(Li)metal batteries.In this work,Li closo-borohydride,Li_(2)B_(12)H_(12),is introduced to poly(vinylidene fluoride)-Li-bis-(trifluoromethanesulfonyl)imide(PVDF-LiTFSI)with a bound N-methyl pyrrolidone plasticizer to form a novel CPE.This CPE shows superb Li^(+)conduction properties,as evidenced by its conductivity of 1.43×10^(-4) S cm^(-1) and Li^(+)transference number of 0.34 at 25℃.Density functional theory calculations reveal that Li_(2)B_(12)H_(12),which features electron-deficient multicenter bonds,can facilitate the dissociation of LiTFSI and enhance the immobilization of TFSI to improve the Li^(+)conduction properties of the CPE.Moreover,the fabricated CPE exhibits excellent electrochemical,thermal,and mechanical stability.The addition of Li_(2)B_(12)H_(12) can help form a protective layer at the anode/electrolyte interface,thereby preventing unwanted reactions.The above benefits of the fabricated CPE contribute to the high compatibility of the electrode.Symmetric Li cells can be stably cycled at 0.2mA cm^(-2) for over 1200 h,and Li||LiFePO_(4) cells can deliver a reversible specific capacity of 140mAh g^(-1) after 200 cycles at 1C at 25℃ with a capacity retention of 98%.

Transient photovoltage and photoluminescence study of exciton dissociation at indium tin oxide/pentacene interface

The exciton dissociation at ITO/pentacene interface is studied by means of transient photovoltage measurement.Opposite to ITO/NPB,ITO/CuPc or ITO/C60 interface where polarity change of transient photovoltage is observed,no interfacial dissociation is found at room temperature,which indicates a lack of Frenkel excitons in pentacene.Temperature-dependent photoluminescence (PL) is investigated.More like the behavior of inorganic semiconductors,the integrated PL intensity exhibits monotonic decrease with increasing temperature.A nonradiative path with characteristic activation energy of 8 meV is found to dominate at room temperature.The PL measurement also indicates that like in inorganic semiconductors,other types of excitation,for example,free carriers,could be responsible for the photoelectric processes.

A novel coral-like garnet for high-performance PEO-based all solid-state batteries

As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.