Electric properties and phase transition behavior in lead lanthanum zirconate stannate titanate ceramics with low zirconate content

The phase transitions, dielectric properties, and polarization versus electric field （P-E） hysteresis loops of Pbo.97Lao.02（Zr0.42Sn0.58-xTix）O3 （0.13≤ x ≤0.18） （PLZST） bulk ceramics were systematically investigated. This study exhibited a sequence of phase transitions by analyzing the change of the P-E hysteresis loops with increasing temperature. The anfiferroelectric （AFE） to ferroelectric （FE） phase boundary of PLZST with the Zr content of 0.42 was found to locate at the Ti content between 0.14 and 0.15. This work is aimed to improve the ternary phase diagram of lanthanum-doped PZST with the Zr content of 0.42 and will be a good reference for seeking high energy storage density in the PLZST system with low-Zr content.

Development Status and Application Analysis of Vehicle to Grid (V2G)

With the shortages of resources,environmental pollution,climate change,and other issues becoming more and more serious,it is extremely urgent to vigorously develop new energy vehicles.As the cost of batteries decrease year by year,the production and quantity of sales of electric vehicles(EVs)in the world,especially in China,increased substantially.In order to make vehicles to grid(V2G)technology better developed and applied in China.The brief introduction to V2G is given at first.Then the development status and specific cases of V2G at home and abroad are summarized.Finally,the problems that V2G may encounter during promotion and application in China are analyzed.Based on the development of the United States and Japan,specific policy recommendations are given in line with the basic national conditions of China.

Water promoted photocatalytic transfer hydrogenation of furfural to furfural alcohol over ultralow loading metal supported on TiO_(2)

Photocatalytic hydrogenation of furfural offers an ideal method for selective biomass upgrading into value-added chemicals or fuel additives under mild conditions. However, it is still challenging to control the product selectivity due to side reactions of functional groups and reactive radical intermediates.Herein, photocatalytic transfer hydrogenation of furfural was studied using the TiO_(2)-based photocatalysts with alcohols as both the solvent and hydrogen donor. Ultralow loading metal supported on TiO_(2),together with adding a small amount of water in the system, were demonstrated to greatly increase the selectivity of furfuryl alcohol product. Electron paramagnetic resonance(EPR), ultraviolet-visible spectroscopy(UV-Vis) and photoluminescence(PL) measurements gave evidence that ultralow loading Pt or Pd on TiO_(2)increase the oxygen vacancy concentration and the photogenerated charge separation efficiency, which accelerates the photocatalytic reduction of furfural. In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) and mechanistic studies confirmed that photogenerated holes and electrons are active species, with dissociatively adsorbed methanol being directly oxidized by holes,furfural hydrogenated by protons and electrons and H_(2)O modifying the intermediate diffusion which contributes to high selectivity of furfuryl alcohol. This work demonstrates a simple approach to design photocatalysts and tune product selectivity in biomass valorization.

A dynamic control structure of liquid-only transfer stream distillation column

The intention of this fundamental work is to explore the manipulation of a mixture of benzene,toluene and o-xylene separated from liquid-only transfer divided-wall column(LTS-DWC).First,two control structures are clearly proposed,including seven component control loops(CS1)and seven temperature control loops(CS2).However,two control structures can handle ±10% feed disturbances rather than larger feed disturbances.Subsequently,an equivalent four-column model by introducing withdraw ratio is developed to discuss the effect of two liquid-only side-stream on the overall reboiler duty.It is indicated that the second liquid-only side-stream withdraw ratio strongly affects the overall energy consumption.Hence,six-component control loops within the fixed second liquid-only side-stream withdraw ratio(CS3)is proposed and the purity of products returns to set value even as facing ±20% feed disturbances.Finally,based on the above results,it is established a temperature control structure(CS4)for controlling fixed second liquid-only side-stream withdraw ratio,which can cope with ±15% disturbances.Inspired by these findings,an insight into the dynamic control of LTS-DWC promotes the industrial implementation of DWC through new liquid-only side-stream configurations.

Removal of pathogenic indicator microorganisms during partial nitrification:the role of free nitrous acid

Digested wastewater contains pathogenic microorganisms and high ammonia concentrations,which can pose a potential risk to public health.Effective removal of pathogens and nitrogen is crucial for the post-treatment of digested wastewater.Partial nitrification-anammox is an energy-saving nitrogen removal process.Free nitrous acid(FNA),an intermediate product of partial nitrification,has the potential to inactivate microorganisms.However,the efficiency and mechanisms of FNA-related inactivation in pathogens during partial nitrification remains unclear.In this study,Enterococcus and Escherichia coli(E.coli)were selected to investigate the efficiency and mechanisms of FNA-related inactivation in partial nitrification process.The results revealed that 83%±13%and 59%±27%of E.coli and Enterococcus were removed,respectively,in partial nitrification process at FNA concentrations of 0.023−0.028 mg/L.When the concentration of FNA increased from 0 to 0.5 mg/L,the inactivation efficiencies of E.coli and Enterococcus increased from 0 to 99.9%and 89.9%,respectively.Enterococcus exhibited a higher resistance to FNA attack compared to E.coli.3D-laser scanning microscopy(3D-LSM)and scanning electron microscopy(SEM)revealed that FNA exposure caused the surface collapse of E.coli and Enterococcus,as well as visible pore formation on the surface of E.coli cells.4',6-Diamidino-2-phenylindole dihydrochloride n-hydrate(DAPI)/propidium iodide(PI)and biomolecule leakage confirmed that inactivation of E.coli and Enterococcus occurred due to breakdown of cell walls and cell membranes.These findings indicate that partial nitrification process can be used for the removal of residual pathogenic microorganisms.

Influence of Direct Current Electric Field on the Formation,Composition and Microstructure of Corrosion Products Formed on the Steel in Simulated Marine Atmospheric Environment

X-ray diffraction, Raman spectroscopy and scanning electron microscopy were employed to investigate the effects of the DC electric field on the composition, formation and structure of corrosion products formed on the surface of the steel immersed in NaCl solution. The results show that goethite （α-FeOOH）, akaganeite （β-FeOOH）, lepidocrocite （γ- FeOOH） and magnetite （Fe3O4） are the major constituents among the corrosion products. The arrangement of different levels of the DC electric field intensity gives rise to the following results. The little higher DC electric field intensity （around 100-200 kV/m） promotes the crystallinity and growth of y-FeOOH; obviously, much higher DC electric field intensity （greater than 400 kV/m） prevents the growth of α-FeOOH and facilitates the generation of Fe3O4. Both the promotional growth of γ-FeOOH and suppression of α-FeOOH growth indicated the weakness of the protectiveness of the rust layer. Consequently, the suppression of the transformation of α-FeOOH from y-FeOOH favors the yield of the Fe3O4, which works as a large cathode area and would be about to quicken the subsequent steel corrosion.

Graphene-nickel nitride hybrids supporting palladium nanoparticles for enhanced ethanol electrooxidation

Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidation removal of CO intermediates is crucial to the durability of EOR-based catalysts.Herein,in order to effectively avoiding the catalyst CO poisoning and improve the durability,the graphene-nickel nitride hybrids(AG-Ni_(3)N)were designed for supporting palladium nanoparticles(Pd/AG-Ni_(3)N)and then used for ethanol electrooxidation.The density functional theory(DFT)calculations demonstrated the introduction of AG-Ni_(3)N depresses the CO absorption and simultaneously promotes the adsorption of OH species for CO oxidation removal.The fabricated Pd/AG-Ni_(3)N catalyst distinctively exhibits excellent electroactivity with the mass catalytic activity of 3499.5 m A mg^(-1) on EOR in alkaline media,which is around 5.24 times higher than Pd/C(commercial catalyst).Notably,the Pd/AG-Ni_(3)N hybrids display excellent stability and durability after chronoamperometric measurements with a total operation time of 150,000 s.

Low temperature ferromagnetism in CaCu_(3)Ti_(4)O_(12)

The low-temperature magnetic order behaviors of perovskite oxide CaCu_(3)Ti_(4)O_(12)(CCTO)ceramics prepared by different methods are discussed.X-ray diffraction,scanning electron microscope,x-ray photoelectron spectroscopy,and direct current(DC)magnetization are used to characterize the structures,microscopic morphologies,valence states,and magnetic properties of the samples.The results show that the magnetic behaviors of CCTO ceramics are very sensitive to the preparation process.The quenched CCTO ceramic and CCTO powders grown in a molten salt crystal,which contain much more oxygen vacancies and Ti^(3+),show the coexistence of weak ferromagnetic order and antiferromagnetic order below the Neel temperature.It suggests that the bound magnetopolaron formed by oxygen vacancies and Ti^(3+)ion composite defects are responsible for the weak ferromagnetic order at low temperature.

Spin selectivity of chiral mesostructured diamagnetic BiOBr films

The chirality-induced spin selectivity(CISS)has been found in the antiferromagnetic and paramagnetic chiral inorganic materials with unpaired electrons,while rarely reported in the spin-paired diamagnetic inorganic materials with spin-pairing energy.Here,we report the CISS in the spin-paired diamagnetic BiOBr endowed with three levels of chiral mesostructures.Chiral mesostructured BiOBr films(CMBFs)were fabricated through a sugar alcohol-induced hydrothermal route.The antipodal CMBFs exhibited chirality-dependent,magnetic field-independent magnetic circular dichroism(MCD)signals,which indicates the existence of spin selectivity.The spin selectivity of CMBFs was speculated to be the result of the competing effect between the externally applied magnetic field and the effective magnetic field arisen from the spin electron motions in chiral potential.The chirality-induced effective magnetic field acts on the magnetic moment of electrons,potentially overcoming the spin-pairing energy and producing opposite energy changes for spin-down and spin-up electrons.

Bandgap engineering of tetragonal phase CuFeS_(2)quantum dots via mixed-valence single-atomic Ag decoration for synergistic Cr(VI)reduction and RhB degradation

Bandgap engineering through single-atom site binding on semiconducting photocatalyst can boost the intrinsic activity,selectivity,carrier separation,and electron transport.Here,we report a mixed-valence Ag(0)and Ag(I)single atoms co-decorated semiconducting chalcopyrite quantum dots(Ag/CuFeS_(2)QDs)photocatalyst.It demonstrates efficient photocatalytic performances for specific organic dye(rhodamine B,denoted as RhB)as well as inorganic dye(Cr(VI))removal in water under natural sunlight irradiation.The RhB degradation and Cr(VI)removal efficiencies by Ag/CuFeS_(2)QDs were 3.55 and 6.75 times higher than those of the naked CuFeS_(2)QDs at their optimal pH conditions,respectively.Besides,in a mixture of RhB and Cr(VI)solution under neutral condition,the removal ratio has been elevated from 30.2%to 79.4%for Cr(VI),and from 95.2%to 97.3%for RhB degradation by using Ag/CuFeS_(2)QDs after 2 h sunlight illumination.The intrinsic mechanism for the photocatalytic performance improvement is attributed to the narrow bandgap of the single-atomic Ag(I)anchored CuFeS_(2)QDs,which engineers the electronic structure as well as expands the optical light response range.Significantly,the highly active Ag(0)/CuFeS_(2)and Ag(I)/CuFeS_(2)effectively improve the separation efficiency of the carriers,thus enhancing the photocatalytic performances.This work presents a highly efficient single atom/QDs photocatalyst,constructed through bandgap engineering via mixed-valence single noble metal atoms binding on semiconducting QDs.It paves the way for developing high-efficiency single-atom photocatalysts for complex pollutions removal in dyeing wastewater environment.

Single entity electrochemistry and the electron transfer kinetics of hydrazine oxidation

The mechanism and kinetics of the electro-catalytic oxidation of hydrazine by graphene oxide platelets randomly decorated with palladium nanoparticles are deduced using single particle impact electrochemical measurements in buffered aqueous solutions across the pH range 2–11. Both hydrazine, N2H4, and protonated hydrazine N2H5+ are shown to be electroactive following Butler-Volmer kinetics, of which the relative contribution is strongly pH-dependent. The negligible interconversion between N2H4 and N2H5+ due to the sufficiently short timescale of the impact voltammetry, allows the analysis of the two electron transfer rates from impact signals thus reflecting the composition of the bulk solution at the pH in question. In this way the rate determining step in the oxidation of each specie is deduced to be a one electron step in which no protons are released and so likely corresponds to the initial formation of a very short-lived radical cation either in solution or adsorbed on the platelet. Overall the work establishes a generic method for the elucidation of the rate determining electron transfer in a multistep process free from any complexity imposed by preceding or following chemical reactions which occur on the timescale of conventional voltammetry.

The “twinkling star” materials: highly superior molecular switches for bioimaging

Artificial molecular switches have been the robust tools for diverse fields of modern science and technology, including molecular machines, smart materials, and bioimaging [1]. The development of new concepts to enable the creation of efficient molecular switches has been a longstanding activity in these fields. Up to date, various kinds of molecular switches have been developed, most of which work between two or more stable states, and the rest of them requires at least an additional energy or chemical stimuli.

Galvanic Corrosion Behavior of Copper-Drawn Steel for Grounding Grids in the Acidic Red Soil Simulated Solution

The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated system.The effect of pH on the corrosion behavior of copper-drawn steel has been investigated using open-circuit potential,potentiodynamic polarization,galvanic current measurement,scanning electron microscopy and scanning vibrating electrode technique techniques.The steel is corroded as anode,while the corrosion of copper plate is protected as cathode.All the results revealed that pH and metallographic structure had a significant influence on the corrosion behavior of copper-drawn steel.With the decrease in pH value from 6 to 2.4,the corrosion rate of copper-drawn steel galvanic couple(Cu-Fe GC)obviously increased in the simulated solution of acidic red soil.The electric field formed by the Cu-Fe GC changes the direction of ion migration between the copper and drawn steel electrodes,which impacts the composition and microstructure of corrosion products formed on the electrode surface.

Catalyst-free,direct electrochemical trifluoromethylation/cyclization of N-arylacrylamides using TfNHNHBoc as a CF_(3) source

A new electrochemical strategy for trifluoromethylation/cyclization using TfNHNHBoc as a CF_(3)source was established.This approach was realized by the direct electrolysis of Tf NHNHBoc under external oxidantfree and catalyst-free conditions,and afforded various trifluoromethylated oxindoles with good functional group compatibility and broad substrate scope.Preliminary mechanistic studies show that the reaction proceeds by a radical process.

Friedel-Crafts trifluoromethylthiolation of electron-rich(hetero)arenes with trifluoromethylthio-saccharin in 2,2,2-trifluoroethanol(TFE)

A promoter-free Friedel-Crafts trifluoromethylthiolation of electron-rich arenes and heteroarenes with N-trifluoromethylthiosaccharin 5 using 2,2,2-trifluoroethanol(TFE) as the solvent was described.The reactions were conducted at 40℃and a variety of common functional groups were compatible.

Electrolyte design strategies towards long-term Zn metal anode for rechargeable batteries

Rechargeable Zinc(Zn)batteries exhibit great potentials as alternative energy storage devices due to their high safety,low cost,and environmental friendliness.However,the long-standing issues of low Coulombic efficiency(CE)and poor cycle stability of Zn anode,derived from dendrite,H_(2)evolution,and passivation are directly related to their thermodynamic instability in aqueous electrolyte,severely shorten the battery's cycle life.Recently reported electrolyte design strategies,which have made great progress to address Zn metal anode problems,are summarized into two categories,that is,aqueous electrolytes about cation-water interaction controlling and interface adjusting,and novel types of electrolytes towards less water,non-aqueous solvents,even no solvents.The final section shows the brief comparisons,including failure mechanisms of electrolyte exhaustion and short circuit for aqueous and nonaqueous electrolyte based full cells respectively,and possible perspectives for future research.

Mg-induced g-C_(3)N_(4) synthesis of nitrogen-doped graphitic carbon for effective activation of peroxymonosulfate to degrade organic contaminants

The nitrogen-doped carbon derived from graphitic carbon nitride(g-C_(3)N_(4))has been widely deployed in activating peroxymonosulfate(PMS)to remove organic pollutants.However,the instability of g-C_(3)N_(4)at high temperature brings challenges to the preparation of materials.The nitrogen-doped graphitic carbon nanosheets(N-GC750)were synthesized by magnesium thermal denitrification.Magnesium undergoes the displacement reaction with small molecules produced by the pyrolysis of g-C_(3)N_(4),thereby effectively fixing carbon on the in-situ template of Mg_(3)N_(2)and avoiding direct product volatilization.N-GC750 exhibited excellent performance during the PMS activation process and bisphenol A(BPA,0.2 g/L)could be thoroughly removed in 30 min.A wide range of pH(3–11),temperature(10–40℃)and common anions were employed in studying the impact on system.Additionally,N-GC750 showed satisfactory reusability in cycle tests and promising applicability in real water samples.Quenching experiments and electron paramagnetic resonance(EPR)measurements indicated that singlet oxygen was the main active species coupled with partial electron transfer in N-GC750/PMS system.Furtherly,the oxidation products were identified,and their ecotoxicity was evaluated.This work is expected to provide a reference for the feasibility of preparing g-C_(3)N_(4)derived carbon materials and meaningful for PMS activation.

Synthesis of S-monofluoromethyl phosphorothioates from P^(Ⅴ)-H compounds and PhSO_(2)SCH_(2)F

S-Monofluoromethyl phosphorothioates represent an important class of organofluorine compounds and are re ported here for the first time.A series of S-monofluoromethyl phosphorothioates are conveniently synthesized from different P^(Ⅴ)-H compounds and PhSO_(2)SCH_(2)F under mild conditions.The method is compatible with common functional groups and provides potential opportunities to synthesize new bioactive molecules for medicinal chemistry.

Quantum interference enhanced thermopower in single-molecule thiophene junctions

Quantum interference(QI)effects,which offer unique opportunities to widely manipulate the charge transport properties in the molecular junctions,will have the potential for achieving high thermopower.Here we developed a scanning tunneling microscope break junction technique to investigate the thermopower through single-molecule thiophene junctions.We observed that the thermopower of 2,4-TPSAc with destructive quantum interference(DQI)was nearly twice of 2,5-TP-SAc without DQI,while the conductance of the 2,4-TP-SAc was two orders of magnitude lower than that of 2,5-TP-SAc.Furthermore,we found the thermopower was almost the same by altering the anchoring group or thiophene core in the control experiments,suggesting that the QI effect is responsible for the increase of thermopower.The density functional theory(DFT)calculations are in quantitative agreement with the experimental data.Our results reveal that QI effects can provide a promising platform to enhance the thermopower of molecular junctions.

In situ self-assembly assisted synthesis of N-doped mesoporous hierarchical carbon aerogels-wrapped Li_(2)ZnTi_(3)O_(8) composite for highrate lithium ion batteries

Reinforcing electronic and ionic conductivity is very important to realize the high-rate Li_(2)ZnTi_(3)O_(8)(LZTO)anode for Lithium-ion batteries(LIBs).Here,we reported a synthetic strategy toward in situ growth of homodispersed Li_(2)ZnTi_(3)O_(8)on ultralight 3D carbon aerogels(CAs)via facile heat treatment and activation process taking LiOH as activating agent.Such an optimized composite obtains a specific surface area of 154.427 m^(2) g^(-1) and a high pore volume.The strong interaction between the LZTO and N-doped CAs,a highly electrical conductivity and multidimensional ion transport channels of the hybrid result in a high capacity,outstanding high-rate performance and long cycle life.As a result,the NPC-LZTO electrode(NPC-LZTO-B)delivers a commendable reversible capacity at high-rate(e.g.162.4 mAh g^(-1) at 5 A g^(-1)(22 C)and 127.3 mAh g^(-1) at 10 A g^(-1))and durable long-term performance(capacity retention of 73% after 4500 cycles at 5 A g^(-1)).Moreover,the kinetic analysis confirms that the feature of pseudocapacitance boosts lithium-ion storage performance at high rate.Porous carbon aerogels frame constructed LZTO nanocomposite electrodes provide a facile way to design high durable LIBs anode.