Cation-vacancy induced Li+ intercalation pseudocapacitance at atomically thin heterointerface for high capacity and high power lithium-ion batteries

It is challenging to create cation vacancies in electrode materials for enhancing the performance of rechargeable lithium ion batteries (LIBs). Herein, we utilized a strong alkaline etching method to successfully create Co vacancies at the interface of atomically thin Co_(3−x)O_(4)/graphene@CNT heterostructure for high-energy/power lithium storage. The creation of Co-vacancies in the sample was confirmed by high-resolution scanning transmission electron microscope (HRSTEM), X-ray photoelectron spectroscopy (XPS) and electron energy loss near-edge structures (ELNES). The obtained Co_(3−x)O_(4)/graphene@CNT delivers an ultra-high capacity of 1688.2 mAh g^(−1) at 0.2 C, excellent rate capability of 83.7% capacity retention at 1 C, and an ultralong life up to 1500 cycles with a reversible capacity of 1066.3 mAh g^(−1). Reaction kinetic study suggests a significant contribution from pseudocapacitive storage induced by the Co-vacancies at the Co_(3−x)O_(4)/graphene@CNT interface. Density functional theory confirms that the Co-vacancies could dramatically enhance the Li adsorption and provide an additional pathway with a lower energy barrier for Li diffusion, which results in an intercalation pseudocapacitive behavior and high-capacity/rate energy storage.

Corrigendum to“Cation-vacancy induced Li+intercalation pseudocapacitance at atomically thin heterointerface for high capacity and high power lithium-ion batteries”[J.Energy Chem.62(2021)281–288]

The authors regret that the wrong image of Fig.1 was uploaded in the paper.The correct one should be:We confirm the discrepancy is restricted to the image of Fig.1 only,the underlying data is correct and unchanged.The authors would like to apologise for any inconvenience caused.

Preparation,characterization and photo-catalytic behavior of WO_3-TiO_2 catalysts with oxygen vacancies

TiO2 photocatalysts compounded with WO3 were prepared via a modified hydrolysis process and the 2%WO3-TiO2 catalysts with different oxygen vacancies were obtained by calcination at 873 K in H2 atmosphere.The catalysts were identified using X-ray diffractometry(XRD),specific surface measurement(BET),electron paramagnetic resonance spectroscopy(EPR), UV-Vis diffusion refraction spectroscopy(DRS),and X-ray photoelectron spectroscopy(XPS).The photocatalytic activity of 2% WO3-TiO2 with different oxygen vacancies was investigated employing splitting of water for O2 evolution.The results indicate that appropriate oxygen vacancies can obviously improve the photocatalytic activity of 2%WO3-TiO2 catalysts,and using Fe 3+ as an electron acceptor under UV irradiation in 12 h,the maximum rate for O2 evolution is 667μmol/(L·h).

WO3 nanofibers on ACF by electrospun for photo-degradation of phenol solution

Electrospun WO_3 nanofibers were fabricated by coaxial electrospinning and directly annealing WCl_6/polyvinylpyrrolidone(PVP) nanofibers on activated carbon fibres(ACF), and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD). The most suitable condition for electrospinning is the mass ratio of WCl_6 to PVP 0.6, appropriate amount DMF and ethanol, a voltage of 28 kV, the reception distance of 15 cm, the humidity range within 10% and 20% and the moving rate of the pump 0.001 mm/s. The photocatalytic activities of WO_3 nanofibers were evaluated by the photo-degradation of phenol solution under the irradiation of 500 W xenon lamp. The results showed that, the sizes of the fibers are about 100 nm, and after being photodegraded for 210 min, the concentration of phenol decreased from 20.05 mg/L to 8.60 mg/L. Thus, the photo-degradation rate of WO_3 nanofibers for phenol solution is 2.87 mg/(L·h).

A new group contribution-based method for estimation of flash point temperature of alkanes

Flash point is a primary property used to determine the fire and explosion hazards of a liquid. New group contribution-based models were presented for estimation of the flash point of alkanes by the use of multiple linear regression(MLR)and artificial neural network(ANN). This simple linear model shows a low average relative deviation(AARD) of 2.8% for a data set including 50(40 for training set and 10 for validation set) flash points. Furthermore, the predictive ability of the model was evaluated using LOO cross validation. The results demonstrate ANN model is clearly superior both in fitness and in prediction performance.ANN model has only the average absolute deviation of 2.9 K and the average relative deviation of 0.72%.

Estimation of half-wave potential of anabolic androgenic steroids by means of QSER Approach

The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.

Synthesis and Crystal Structure of (2-Iodo-5-nitrophenyl)-[1-(1-methylazepan-3-yl)-1H-indol-3-yl]methanone

The title compound （2-iodo-5-nitrophenyl）-[1-（1-methylazepan-3-yl）-lH-indol-3- yl]methanone （C22H22IN303, Mr- 503.07 ） was synthesized by the reaction of 3-（2-iodo-5- nitrobenzoyl）indole with 2-chloromethyl-1-methylpiperidine. Its chemical structure was determined by 1H NMR, 13C NMR, DEPT, COSY, HMQC, HMBC, HRMS and X-ray single-crystal diffraction. The crystal belongs to the triclmic system, space group P1 with a = 9.153（4）, b = 10.409（3）, c = 11.882（4） A, a = 71.84（3）, β = 78.67（3）, ）, = 75.49（3）°, V = 1032.7（6） A3, Z = 2, Dc= 1.619 g/era3, = 1.579 mm-1, F（000） = 504, R = 0.0270 and wR = 0.0498 for 3634 observed reflections with I 〉 20（/）. X-ray analysis shows that the indole ring forms a dihedral angle of 84.57（12）° with the iodobenzene ring and the azepane ring adopts a twisted chair conformation. Weak C-H...O hydrogen bonding contributes to the stability and packing of the structure.

Constructing a fluorinated interface layer enriched with Ge nanoparticles and Li-Ge alloy for stable lithium metal anodes

Lithium metal batteries(LMBs)based on metallic Li exhibit high energy density to be competent for advanced energy storage applications.However,the unstable solid electrolyte interphase(SEI)layer due to continuous decomposition of electrolytes,and the attendant problem of Li dendrite growth frustrate their commercialization process.Herein,a hybrid SEI comprising abundant LiF,lithiophilic Li-Ge alloy,and Ge nanoparticles is constructed via a simple brush coating method.This fluorinated interface layer with embedded Ge-containing components isolates the Li anode from the corrosive electrolyte and facilitates homogenous Li nucleation as well as uniform growth.Consequently,the modified Li anode exhibits remarkable stability without notorious Li dendrites,delivering stable cycling lives of more than 1000 h for symmetric Li||Li cells and over 600 cycles for Li||Cu cells at 1 mA·cm^(−2).Moreover,the reinforced Li anodes endow multiple full-cell architectures with dramatically improved cyclability under different test conditions.This work provides rational guidance to design an artificial hybrid SEI layer and would stimulate more ideas to solve the dendrite issue and promote the further development of advanced LMBs.

Simulation of ^(13)C NMR chemical shifts of carbinol carbon atoms using quantitative structure-spectrum relationships

A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear regression,contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R2= 0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability,the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%,respectively,for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method.

Estimation of surface tension of organic compounds using quantitative structure-property relationship

A novel quantitative structure-property relationship(QSPR) model for estimating the solution surface tension of 92 organic compounds at 20 °C was developed based on newly introduced atom-type topological indices.The data set contained non-polar and polar liquids,and saturated and unsaturated compounds.The regression analysis shows that excellent result is obtained with multiple linear regression.The predictive power of the proposed model was discussed using the leave-one-out(LOO) cross-validated(CV) method.The correlation coefficient(R) and the leave-one-out cross-validation correlation coefficient(RCV) of multiple linear regression model are 0.991 4 and 0.991 3,respectively.The new model gives the average absolute relative deviation of 1.81% for 92 substances.The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.

Preparation of core-shell magnetic Fe_3O_4@SiO_2-dithiocarbamate nanoparticle and its application for the Ni^(2+), Cu^(2+) removal

A novel magnetic nanoparticles-based dithiocarbamate absorbent（Fe3O4@SiO2-DTC） with core-shell structure was synthesized under mild conditions and used in aqueous solution Ni2＋ and Cu2＋ ions treatment. The structure, morphology and magnetic properties of the adsorbent were characterized by Xray diffraction（XRD）, fourier transformed infrared spectroscopy（FTIR）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and vibrating sample magnetometer（VSM）.Fe3O4@SiO2-DTC exhibited a typical superparamagnetic with a saturation magnetization value of52.7 emu/g, which could be rapidly separated from aqueous solution under external magnetic field. We investigated the effects of solution p H, adsorption time, and the initial concentration of heavy metal ions on the adsorption of Ni2＋ and Cu2＋. The adsorption equilibrium times of Ni2＋and Cu2＋ on Fe3 O4@SiO2-DTC were reached at 15 min and 90 min, respectively. The adsorption kinetic data were fitted to the pseudosecond-order model, and the adsorption data were consistent with the Frenudlich isotherm model. When the initial concentration of heavy metal ions was 250 mg/L, the maximum adsorption capacity of Ni2＋ and Cu2＋ at room temperature was 235.23 mg/g and 230.49 mg/g, respectively. In addition, we discussed the plausible adsorption mechanism. The results indicated that the adsorption was mainly dominated by chelation.

A dsDNA-lighted fluorophore for monitoring protein-ligand interaction through binding-mediated DNA protection

Because of their important roles in cellular functions, life activities, drug screening, and disease treatment, the development of efficient methods for monitoring protein-ligand interaction is essential. In this study, inspired by our previous studies on DNA conformation-selective fluorescent indicators, we developed a new sensing platform for monitoring protein-ligand interaction and detecting protein activity based on binding-mediated DNA protection and the dsDNA-lighted fluorophore, ethyl-4-[3,6-bis(1-methyl-4-vinylpyridium iodine)-9 H-carbazol-9-yl)] butanoate(EBCB). The ligand was purposefully linked to the 3?-terminal of a hairpin DNA probe to selectively bind with the target protein and protect the DNA from cleavage by exonuclease III. By virtue of EBCB's outstanding capacity to discriminate DNA conformation, the protein-ligand interaction could be effectively monitored through a fluorescence change in EBCB. A high fluorescence signal was detected when the hairpin DNA was protected in the presence of the target protein, whereas a much lower signal was observed in the presence of nontarget proteins.Our results demonstrated that the proposed strategy had high potential, such as high selectivity and relatively high sensitivity, for monitoring protein-ligand interaction and detecting protein activity. We believe these results will pave the way for applying dsDNA-lighted fluorophore EBCB as an effective signal transducer for DNA conformation transformation-mediated biochemical sensing.

Practical and sustainable approach for clean preparation of 5-organylselanyl uracils

An eco-friendly,sustainable and practical method for the efficient preparation of 5-organylselanyl uracils through the electrochemical selenylation of uracils and dio rganyl diselenides at room temperature under oxidant-and external electrolvte-free conditions was developed.

Synthesis and luminescence properties of CeF_3:Tb^(3+) nanodisks via ultrasound assisted ionic liquid method

CeF3 and CeF3：Tb3＋ nanocrystals were successfully synthesized by the ultrasound assisted ionic liquid （IL） method at room temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, selected area electron diffraction （SAED）, high-resolution transmission electron micrographs （HRTEM） and photoluminescence （PL） spectra were employed to characterize the nanocrystals. The results of XRD indicated that the obtained samples crystallized well with a hexagonal phase crystal structure. SEM and TEM images demonstrated that the obtained CeF3：Tb3＋ nanocrystals had a discoid shapein the presence of ultrasound and IL, whereas only granular nanoparticles were obtained by magnetic stirring. The possible formation mechanisms of the crystal growth were proposed. The PL spectra of the CeF3：Tb3＋ nanodisks exhibited a strong green emission when excited at 254 nm. Furthermore, the photoluminescence intensity of CeF3：Tb3＋ of the discoid particles was largely improved com-pared with that of the granular nanoparticles.

Solvent-dependent selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under neat conditions

An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural(HMF) to 2,5-furandicarboxylic acid(FDCA) with atmospheric dioxygen as the sole oxidant under acid-,base-,metal-,and external initiator-free conditions in minimal solvent was reported.In the present reaction,the 1,2-diethoxyethylane has a dual role:reaction medium and free-radical initiato r.The FDCA easily crystallizes during the reaction and was simple purified via recrystallization to provide the pure FDCA.

Sustainable routes for quantitative green selenocyanation of activated alkynes

Most organic reactions require the usage of volatile organic compounds in the synthesis, work-up and purification processes, thus resulting in major environmental pollution and high manufacturing cost. By using cheap biomass lactic acid as the reaction media and catalyst, a sustainable protocol for the synthesis of Z-3-selenocyanatoacrylates and analogues through green selenocyanation of activated alkynes has been achieved. A principal advantage of this protocol is that the usage of organic volatile compounds can be avoided entirely, as the conversion of substrate is almost quantitative or quantitative with a minimal amount of lactic acid employed as reaction media, and the pure products can be conveniently collected through water precipitation.

An Enzyme-Free Amperometric Sensor Based on Self-Assembling Ferrocene-Conjugated Oligopeptide for Specific Determination of L-Arginine

Main observation and conclusion An enzyme-free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene(Fc)linker as ferrocene-Gly-Gly-Gly-Gly-Phe-Gly-His-Ile-His-Glu-Gly-Tyr-Gly-Gly-Gly-Gly-Lys-(CH_(2))_(4)-dithiocyclopentane self-assembled on gold substrate was designed and fabricated for specific determination of L-arginine(L-Arg).The detection mechanism is based on conformational change of surface-immobilized peptide induced by the target L-Arg,which was confirmed via SEM,TEM,AFM,XPS,and SPR studies.The binding affinity and the recognition feasibility of immobilized specific and non-specific peptides were also assessed using electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and differential pulse voltammetry(DPV).The proposed method can serve as“signal-on”sensor for detection of L-Arg down to 31 pmol/L with broad linear range(0.0001 to 10μmol/L).Furthermore,the Fc-conjugated specific peptide sensor was successfully applied to the determination of L-Arg in pig serums with a recovery rate of 97.5%—106.9%,and its test results are in good agreement with that of chromatographic instrument,evidencing that the oligopeptide-based sensor can be served as a simple and enzyme-free biosensing platform towards L-Arg for future application.

Visible-light-initiated tandem synthesis of difluoromethylated oxindoles in 2-MeTHF under additive-,metal catalyst-,external photosensitizer-free and mild conditions

An efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visiblelight induced one-pot tandem reaction of N-arylacrylamides,difluoroacetic acid and Ph I(OAc)_(2)was developed.This reaction proceeded in the absence of any additive,base,metal-catalyst and external photosensitizer,using cheap and easily available CHF_(2)CO_(2)H as the difluoromethylation reagent and bulk biomass-derived 2-Me THF as the sole solvent.26 Examples of N-arylacrylamide substrates were investigated,and all of them successfully underwent difluoromethylation to deliver the target products in good to excellent yields.

Domino Cross Dehydrogenative Coupling of 2-Aryl Acetals with Ketones Using DDQ as Oxidant and Reactant Precursor

A novel domino cross dehydrogenative coupling of 2-aryl acetals with unmodified ketones has been developed, using DDQ as both the oxidant and reactant precursor.

利用新颖的局部及全局分子描述符估算有机过氧化物的热分解温度（英文）

热分解温度是评估有机过氧化物火灾危险程度最重要的参数之一。本文提出一种估算有机过氧化物热分解温度的定量新方法。38种有机过氧化物被随机分为训练集和测试集,分子局部描述符AT1,AT2,AT3,AT4,AT5,AT6和全局描述符ATC表征分子结构特征。建立了一个准确的估算有机过氧化物热分解温度的定量构效关系模型,多元线性关系模型的相关系数、标准偏差和留一法检验的相关系数分别为0.9795,6.5676°C和0.9328,预测结果的平均相对误差仅为3.86%。模型稳定性采用留一法和外检验进行验证,分子结构参数对有机过氧化物的热分解温度的影响进行合理的解释。与相关文献结果比较表明利用分子局部描述符AT_1,AT_2,AT_3,AT_4,AT_5,AT_6和全局描述符ATC建立定量构效关系方法估算有机过氧化物的热分解温度是一种有效的方法。