In this study,we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide(C16H36O4Zr)and chloroiridic acid(H2IrCl6)via a sol–gel route.To explore the effect of ZrO2 content on the sur...In this study,we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide(C16H36O4Zr)and chloroiridic acid(H2IrCl6)via a sol–gel route.To explore the effect of ZrO2 content on the surface properties and electrochemical behavior of electrodes,we performed physical characterizations and electrochemical measurements.The obtained results revealed that the binary oxide coating was composed of rutile IrO2,amorphous ZrO2,and an IrO2–ZrO2 solid solution.The IrO2–ZrO2 binary oxide coatings exhibited cracked structures with flat regions.A slight incorporation of ZrO2 promoted the crystallization of the active component IrO2.However,the crystallization of IrO2 was hindered when the added ZrO2 content was greater than 30at%.The appropriate incorporation of ZrO2 enhanced the electrocatalytic performance of the pure IrO2 coating.The Ti/70at%IrO2–30at%ZrO2 electrode,with its large active surface area,improved electrocatalytic activity,long service lifetime,and especially,lower cost,is the most effective for promoting oxygen evolution in sulfuric acid solution.展开更多
In this work,the discharge properties and electrochemical behaviors of as-cast AZ80-La-Gd anode for Mg-air battery have been investigated and compared with the AZ80 anode.The microstructure evolution,electrochemical b...In this work,the discharge properties and electrochemical behaviors of as-cast AZ80-La-Gd anode for Mg-air battery have been investigated and compared with the AZ80 anode.The microstructure evolution,electrochemical behaviors and surface morphologies after discharge have been discussed to connect the discharge properties.The results indicate that the modified AZ80-La-Gd is an outstanding candidate for anode for Mg-air batter,which has high cell voltage,stable discharge curves,good specific capacity and energy,and good anodic efficiency.It exhibits the best anodic efficiency,specific capacity and energy of 76.45%,1703.6 mAh·g^(-1)and 2186.3 mWh·g^(-1),respectively,which are20.24%,18.92%and 25.71%higher than values for AZ80 anode.Such excellent discharge performance is attributed to the Al-RE particles.They refine the Mg_(17)Al_(12)phase and therefore improve the self-corrosion resistance and desorption ability of AZ80 anode.展开更多
Three kinds of pure magnesium anode materials with different grain sizes were prepared by extrusion at different temperatures.The grain size of each sample was calculated,then the effect of grain size on the electroch...Three kinds of pure magnesium anode materials with different grain sizes were prepared by extrusion at different temperatures.The grain size of each sample was calculated,then the effect of grain size on the electrochemical properties of pure magnesium anode was investigated by chemical immersion hydrogen test,potentiodynamic polarization scanning,constant current discharge and electrochemical impedance spectroscopy.As the extrusion temperature increases from 180℃ to 250℃,the average grain size of pure magnesium increases from 20m to 30m,and the pure magnesium extruded at 250℃ has the best electrochemical performance as magnesium anode,with the discharge potential of−1.571 V(vs.SCE).Plastic deformation process is a convenient method that can change the microstructure and improve the electrochemical behavior of magnesium anode.展开更多
The electrochemical behavior of Mg^(2+)and Al^(3+)in LiCl-KCl(mass 4:1)melt at 973 K was studied on a Mo electrode systematically by cyclic voltammetry,square wave voltammetry and chronopotentiometry.The results showe...The electrochemical behavior of Mg^(2+)and Al^(3+)in LiCl-KCl(mass 4:1)melt at 973 K was studied on a Mo electrode systematically by cyclic voltammetry,square wave voltammetry and chronopotentiometry.The results showed that the reductions of Mg^(2+)and Al^(3+)were reversible processes controlled by the rate of the mass transfer.When Mg^(2+)and Al^(3+)coexisted in LiCl-KCl melt,they had no significant effect on the reduction potential of each other.The equilibrium potentials of Mg^(2+)/Mg and Al^(3+)/Al were obtained by open circuit potential method.Their apparent standard potentials were also calculated in this system and the values were-2.52 V vs Cl_(2)/Cl^(−),-1.66 V vs Cl_(2)/Cl^(−),respectively.Correspondingly,the apparent Gibbs free energies of Mg^(2+)/Mg and Al^(3+)/Al were-485.71 kJ/mol^(-1),-480.78 kJ/mol^(-1).Finally,potentiostatic electrolysis was performed on a Mo electrode in LiCl-KCl-MgCl_(2)-AlCl_(3)(the mass ratio of MgCl_(2) to AlCl_(3) was 10:1)melt at different potentials.The components of the deposits were characterized by scanning electron microscope and energy dispersive spectroscopy.The study revealed that the content of Al in the deposit decreased as the overpotential increased and Al tended to segregate at the grain boundaries.展开更多
The electroplating behavior of Zn P alloy on copper from light acid chloride solutions (LACS) was investigated using cyclic voltammetry and linear potential sweep method. It is found that, under the experimental condi...The electroplating behavior of Zn P alloy on copper from light acid chloride solutions (LACS) was investigated using cyclic voltammetry and linear potential sweep method. It is found that, under the experimental conditions, the concentrations of H 3PO 3 and ascorbic acid in LACS change the codeposition mechanism of Zn P alloy, the addition of H 3PO 3 into LACS promotes the three dimentional (3 D) instantaneous nucleation/growth, while the addition of ascorbic acid promotes the two dimentional (2 D) instantaneous nucleation and layer by layer growth. H 3PO 3 and zinc ions inhibit the deposition each other. The experimental results also show that H 3PO 3 in the LACS can be reduced on the cathode individually, and low pH value of the LACS promotes the reduction of H 3PO 3.展开更多
An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded mo...An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction(XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl_2 film due to Cl ions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg_(17)Al_(12) phase containing experimental alloys. The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg_2 Pb and Mg_(17)Al_(12) somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.展开更多
This investigation describes the one step preparation of potassium carbonate by electrolysis of potas-sium chloride solution in electrolyzers with various Nation membranes.Potassium bicarbonate solution wasfed to the ...This investigation describes the one step preparation of potassium carbonate by electrolysis of potas-sium chloride solution in electrolyzers with various Nation membranes.Potassium bicarbonate solution wasfed to the cathode compartment,where it was converted into carbonate by reaction with the hydroxideformed at cathode.Because of the low OH^- concentration in the cathode compartment,the back migrationof OH^- through the membrane was almost negligible,resulting in a higher current efficiency,say 90% or more.In this study,electroconductivity,mass transfer,current efficiency and cell voltage were measured.Thefeasibility of the process was discussed and the optimal conditions examined.展开更多
The V_2C compound,belonging to the group of two-dimensional transition metal carbonitrides,or MXenes,has demonstrated a promising electrochemical performance in capacitor applications in acidic electrolytes;however,th...The V_2C compound,belonging to the group of two-dimensional transition metal carbonitrides,or MXenes,has demonstrated a promising electrochemical performance in capacitor applications in acidic electrolytes;however,there is evidence to suggest that V_2C is unstable in an acidic environment.On the other hand,the performance of V_2C in neutral aqueous electrolytes is still moderate,and has not yet been systematically studied.The charge storage mechanism in a V_2C electrode,employed in neutral aqueous electrolytes,is investigated via cyclic voltammetry testing and in situ x-ray diffraction(XRD).Good specific capacitances are achieved,specifically208 F/g in 0.5 M Li_2SO_4,225 F/g in 1 M MgSO_4,120 F/g in 1 M Na_2 SO_4,and 104 F/g in 0.5 M K_2SO_4.Using in situ XRD,we observe that,during the charge and discharge process,the c-lattice parameter shrinks or expands by up to 0.25 A in MgSO_4,and 0.29 A in Li_2SO_4 which demonstrates the intercalation/de-intercalation of cations into the d-V_2C layer.展开更多
The effect of solution pH,Cl^- concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microsc...The effect of solution pH,Cl^- concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscopy and X-ray photoelectron spectroscopy.The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0,below which the anodic polarization curves of the steel are actively dissolved.The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl^- concentration and solution temperature.Pits are initiated on the sample surface in the presence of the Cl^- and gradually developed into uniform corrosion with increasing the Cl^- concentrations.Moreover,the corrosion is more serious with an increase in solution temperature.展开更多
Titanium alloy plays a crucial role in the electrochemical field due to its excellent corrosion resistance.The passivation and dissolution behaviors of Ti-6.5Al-2Zr-1Mo-1V(TA15)alloy in Na Cl solution were studied by ...Titanium alloy plays a crucial role in the electrochemical field due to its excellent corrosion resistance.The passivation and dissolution behaviors of Ti-6.5Al-2Zr-1Mo-1V(TA15)alloy in Na Cl solution were studied by simulating the electrochemical machining process in a rotating condition,which made the anode in a state with alternating high and low current density.Electron probe micro analysis,ultra-depth microscope,scanning electron microscope,and X-ray photoelectron spectrometer were used to reveal the evolution of TA15 under fluctuating current density.The existence state of the passivation film on TA15 surface was closely related to the pulse frequency of the periodically fluctuating current density.At higher pulse frequency of 0.20 Hz,the material was hardly dissolved because passivation dominated the electrolysis behavior,while at lower pulse frequency of 0.01 Hz,the passivation and dissolution behaviors occurred alternately with the variation of the current density.Herein,the thickness of the passivation film was inversely proportional to the applied current density.Due to the different electrochemical characteristics of a phase andβphase,the surface of the TA15 changed from being smooth to porous after a period.In addition,the change of microstructure affected the content of O^(2–)and exposed the suboxides of titanium.In a word,the change of pulse frequency and current density affected the electrochemical behavior of TA15,which was different from the conventional steady condition.展开更多
The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigat...The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigated Mg–Y–Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios.Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates,but also leads to the precipitation of Mg_(24)Y_(5) phase.The corrosion rate of Mg–Y–Zn based alloys greatly increases from 7.4 mg·cm^(−2)·day^(−1) to 11.3 mg·cm^(−2)·day^(−1) with increasing the Y/Zn mole ratio up to 3.It should be attributed to the decreasing size of LPSO phase plates as cathodes,further increasing the hydrogen evolution kinetics.The related corrosion mechanism is discussed in details.展开更多
To address the issues of large volume change and low conductivity of silicon(Si)materials,carbon coatings have been widely employed as surface protection agent and conductive medium to encapsulate the Si materials,whi...To address the issues of large volume change and low conductivity of silicon(Si)materials,carbon coatings have been widely employed as surface protection agent and conductive medium to encapsulate the Si materials,which can improve the electrochemical performance of Si-based electrodes.There has been a strong demand to gain a deeper understanding of the impact of efficient carbon coating over the lithiation and delithiation process of Si materials.Here,we report the first observation of the extended two-phase transformation of carbon-coated Si nanoparticles(Si/C)during electrochemical processes.The Si/C nanoparticles were prepared by sintering Si nanoparticles with polyvinylidene chloride precursor.The Si/C electrode underwent a two-phase transition during the first 20 cycles at 0.2 C,but started to engage in solid solution reaction when the ordered compact carbon coating began to crack.Under higher current density conditions,the electrode was also found to be involved in solid solution reaction,which,however,was due to the overwhelming demand of kinetic property rather than the breaking of the carbon coating.In comparison,the Si/C composites prepared with sucrose possessed more disordered and porous carbon structures,and presented solid solution reaction throughout the entire cycling process.展开更多
Azaperone,with anti-anxiety and anti-aggressive activities used in veterinary medicine,is a member of the butyrophenone class.It is ordinarily utilized for a wide range of indications,such as sedation,obstetrics,and a...Azaperone,with anti-anxiety and anti-aggressive activities used in veterinary medicine,is a member of the butyrophenone class.It is ordinarily utilized for a wide range of indications,such as sedation,obstetrics,and anesthesia.In this research,an improved synthetic route is presented for azaperone using a phase-transfer catalyst(PTC).In general,it was synthesized as a dopamine antagonist in four steps.The bis(2-chloroethyl)amine intermediate is easily obtained after the conversion of the alcohol groups into the chloride leaving group using thionyl chloride(95%yields).The alkylation of commercially available 2-amino pyridine in the presence of PTC was then carried out,giving 1-(pyridin-2-yl)piperazine with 75%yield.1-(Pyridin-2-yl)piperazine was finally alkylated using 4-chloro-1-(4-fluorophenyl)butan-1-one to achieve azaperone with 60%yield.The butyrophenone intermediate was obtained via the Friedel-Crafts reaction of fluorobenzene with 4-chlorobutyryl chloride in the presence of AlCl3.High efficiency,gentle reaction conditions,and fast and simple procedure are the advantages of this method.Also,the electrochemical oxidation behaviour of azaperone was investigated using cyclic and differential pulse voltammetry techniques.Cyclic voltammetric studies indicated an irreversible process for azaperone electro-oxidation with a peak potential of 0.78 V in a phosphate buffer solution(pH=7.0)vs.Ag/AgCl(saturated KCl)electrode.The value of the peak current vs.the azaperone concentration was enhanced linearly in the range of 10―70μmol/L,and the detection limit was found to be 3.33μmol/L.展开更多
Heterocyclic compounds are the promising biological compounds as nature-friendly for the corrosion protection of metallic surface.In this work,three heterocyclic compounds such as 1-azanaphthalene-8-ol(8-AN),2-methylq...Heterocyclic compounds are the promising biological compounds as nature-friendly for the corrosion protection of metallic surface.In this work,three heterocyclic compounds such as 1-azanaphthalene-8-ol(8-AN),2-methylquinoline-8-ol(8-MQ),and 8-quinolinol-5-sulfonic acid(8-QSA)were used as green compounds,and their anti-corrosion performance for AZ31 Mg in saline water was discussed on the basis of impedance interpretation and surface analysis.Findings found that the electrochemical performance was improved in the order of 8-AN>8-MQ>8-QSA,demonstrating the electron donor effect of N-heterocycles to form coordination complexes on the magnesium surface.From the electrochemical performance,the protective layer constructed at the optimal concentration reinforces the barrier against aggressive environments,with potential inhibition efficiency of 87.4%,99.0%,and 99.9%for 8-QSA,8-MQ,and 8-AN,respectively.Quantum chemical parameters and electron density distribution for free organic species in the absence and presence of Mg^(2+)cation were evaluated using density functional theory(DFT).Upon the formation of coordination complexes between organic compound and Mg^(2+),energy gap underwent change about ΔE=5.7 eV in the 8-AN/Mg^(2+)system.Furthermore,the adsorption of heterocyclic compounds on Mg surface reveals the formation of strong covalent bonds with Mg atoms,which further confirmed by the electron density difference and projected density of states analyses.Based on theoretical calculations,three inhibitors can adsorb on the metal surface in both parallel and perpendicular orientations via C,O and N atoms.In the parallel configuration,the C-Mg,N-Mg and O-Mg bond distances are between 2.11 and 2.25˚A,whereas the distances in the case of perpendicular adsorption are between 2.20 and 2.40˚A(covalent bonds via O and N atoms).The results indicated that parallel configurations are energetically more stable,in which the adsorption energies are-4.48 eV(8-AN),-4.28 eV(8-MQ)and-3.82 eV(8-QSA)compared to that of perpendicular adsorption(-3.65,-3.40,and-2.63 eV).As a result,experimental and theoretical studies were in well agreement and confirm that the nitrogen and oxygen atoms will be the main adsorption sites.展开更多
Porous Al-Mg alloys with different nominal compositions were successfully fabricated via elemental powder reactive synthesis, and the phase composition, pore structure, and corrosion resistance were characterized with...Porous Al-Mg alloys with different nominal compositions were successfully fabricated via elemental powder reactive synthesis, and the phase composition, pore structure, and corrosion resistance were characterized with X-ray diffractometer, scanning electron microscope and electrochemical analyzer. The volume expansion ratio, open porosity and corrosion resistance in 3.5%(mass fraction) Na Cl aqueous solution of the alloys increase at first and then decrease with the increase of Mg content. The maxima of volume expansion ratio and open porosity are 18.3% and 28.1% for the porous Al-56%Mg(mass fraction) alloy, while there is the best corrosion resistance for the porous Al-37.5% Mg(mass fraction) alloy. The pore formation mechanism can be explained by Kirkendall effect, and the corrosion resistance can be mainly affected by the phase composition for the porous Al-Mg alloys. They would be of the potential application for filtration in the chloride environment.展开更多
The semiconductive characteristics of clectron-transfrring proteins in living cells E coli was investigated by electrochemsical impedance spectroscopy(EIS). We found that the electrochemical impedance of living cells ...The semiconductive characteristics of clectron-transfrring proteins in living cells E coli was investigated by electrochemsical impedance spectroscopy(EIS). We found that the electrochemical impedance of living cells as a function of temprature followed the Arrhenius equation for semiconductors. This result shows a strong evidence to prove the semiconductive behavior of展开更多
The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are e...The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are evaluated.The grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing alloy.Note that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing alloy.The electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical activity.Using In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca alloying.The micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly improved.The In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.展开更多
The porous metallic biomaterials have attracted significant attention for implants because their lower young's modulus matches the human bones, which can eliminate the stress shielding effect and facilitate the gr...The porous metallic biomaterials have attracted significant attention for implants because their lower young's modulus matches the human bones, which can eliminate the stress shielding effect and facilitate the growth of bone tissue cells. The porous metallic biomaterials fabricated by selective laser melting (SLM) have broad prospects, but the surface of the SLM-built porous structure has been severely adhered with unmelted powders, which affects the forming accuracy and surface quality. The porous metallic biomaterials face the corrosion problem of complex body fluid environments during service, so their corrosion resistance in the human body is extremely important. The surface quality will affect the corrosion resistance of the porous metallic biomaterials. Therefore, it is necessary to study the effect of post-treatment on the corrosion resistance of SLMed samples. In this work, the mechanical response and the electrochemical corrosion behavior in simulated body fluid of diamond and pentamode metamaterials Ti-6Al-4V alloy fabricated by SLM before and after sandblasting were studied. After sandblasting, the mechanical properties of the two porous metallic biomaterials were slightly improved, and the self-corrosion potential and pitting potential were more negative;meanwhile, the self-corrosion current density and passive current density increased, indicating that its corrosion performance decreased, and the passive film stability of sandblasted samples got worse.展开更多
For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nano...For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nanorods were prepared by facile high-temperature solid-state reaction.The as-prepared materials were well studied and they show outstanding electrochemical behavior.We assembled hybrid supercapacitors with commercial activated carbon(YEC-8 A)as anode and K1.04Mn8 O16 as cathode.It shows high energy and power densities.Li-ion capacitors reach a high energy density of 127.61 Wh kg-1 at the power density of 99.86 W kg-1 and Na-ion capacitor obtains 170.96 Wh kg-1 at 133.79 W kg-1.In addition,the hybrid supercapacitors demonstrate excellent cycling performance which maintain 97%capacitance retention for Li-ion capacitor and 85%for Na-ion capacitor after 10,000 cycles.展开更多
Composite electrodes prepared by cation exchange resins and activated carbon(AC)were used to adsorb Ⅴ(Ⅳ)in capacitive deionization(CDI).The electrode made of middle resin size(D860/AC M)had the largest specific surf...Composite electrodes prepared by cation exchange resins and activated carbon(AC)were used to adsorb Ⅴ(Ⅳ)in capacitive deionization(CDI).The electrode made of middle resin size(D860/AC M)had the largest specific surface area and mesoporous content than two other composite electrodes.Electrochemical analysis showed that D860/AC M presents higher specific capacitance and electrical double layer capacitor than the others,and significantly lower internal diffusion impedance.Thus,D860/AC M exhibits the highest adsorption capacity and rate of Ⅴ(Ⅳ)among three electrodes.The intra-particle diffusion model fits well in the initial adsorption stage,while the liquid film diffusion model is more suitable for fitting at the later stage.The pseudo-second-order kinetic model is suited for the entire adsorption process.The adsorption of Ⅴ(Ⅳ)on the composite electrode follows that of the Freundlich isotherm.Thermodynamic analysis indicates that the adsorption of Ⅴ(Ⅳ)is an exothermic process with entropy reduction,and the electric field force plays a dominant role in the CDI process.This work aims to improve our understanding of the ion adsorption behaviors and mechanisms on the composite electrodes in CDI.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. U1802253, 51974025 and 51674026)the Guangxi Innovation-Driven Development Project (No. AA18242042-1)+1 种基金the Beijing Natural Science Foundation of China (No. 2182040)the Fundamental Research Funds for the Central Universities (FRF22TT-19-001)
文摘In this study,we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide(C16H36O4Zr)and chloroiridic acid(H2IrCl6)via a sol–gel route.To explore the effect of ZrO2 content on the surface properties and electrochemical behavior of electrodes,we performed physical characterizations and electrochemical measurements.The obtained results revealed that the binary oxide coating was composed of rutile IrO2,amorphous ZrO2,and an IrO2–ZrO2 solid solution.The IrO2–ZrO2 binary oxide coatings exhibited cracked structures with flat regions.A slight incorporation of ZrO2 promoted the crystallization of the active component IrO2.However,the crystallization of IrO2 was hindered when the added ZrO2 content was greater than 30at%.The appropriate incorporation of ZrO2 enhanced the electrocatalytic performance of the pure IrO2 coating.The Ti/70at%IrO2–30at%ZrO2 electrode,with its large active surface area,improved electrocatalytic activity,long service lifetime,and especially,lower cost,is the most effective for promoting oxygen evolution in sulfuric acid solution.
基金financially supported by the National Natural Science Foundation of China(Grant No.51974082)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)
文摘In this work,the discharge properties and electrochemical behaviors of as-cast AZ80-La-Gd anode for Mg-air battery have been investigated and compared with the AZ80 anode.The microstructure evolution,electrochemical behaviors and surface morphologies after discharge have been discussed to connect the discharge properties.The results indicate that the modified AZ80-La-Gd is an outstanding candidate for anode for Mg-air batter,which has high cell voltage,stable discharge curves,good specific capacity and energy,and good anodic efficiency.It exhibits the best anodic efficiency,specific capacity and energy of 76.45%,1703.6 mAh·g^(-1)and 2186.3 mWh·g^(-1),respectively,which are20.24%,18.92%and 25.71%higher than values for AZ80 anode.Such excellent discharge performance is attributed to the Al-RE particles.They refine the Mg_(17)Al_(12)phase and therefore improve the self-corrosion resistance and desorption ability of AZ80 anode.
基金support of the National Key Research and Development Program of China(No.2016YFB0101600)the Fundamental Research Funds for the Central Universities of Chongqing University(No.106112016CDJXZ138811 and No.106112017CDJPT280001).
文摘Three kinds of pure magnesium anode materials with different grain sizes were prepared by extrusion at different temperatures.The grain size of each sample was calculated,then the effect of grain size on the electrochemical properties of pure magnesium anode was investigated by chemical immersion hydrogen test,potentiodynamic polarization scanning,constant current discharge and electrochemical impedance spectroscopy.As the extrusion temperature increases from 180℃ to 250℃,the average grain size of pure magnesium increases from 20m to 30m,and the pure magnesium extruded at 250℃ has the best electrochemical performance as magnesium anode,with the discharge potential of−1.571 V(vs.SCE).Plastic deformation process is a convenient method that can change the microstructure and improve the electrochemical behavior of magnesium anode.
基金the National Natural Science Foundation of China(Grant No.51804277).
文摘The electrochemical behavior of Mg^(2+)and Al^(3+)in LiCl-KCl(mass 4:1)melt at 973 K was studied on a Mo electrode systematically by cyclic voltammetry,square wave voltammetry and chronopotentiometry.The results showed that the reductions of Mg^(2+)and Al^(3+)were reversible processes controlled by the rate of the mass transfer.When Mg^(2+)and Al^(3+)coexisted in LiCl-KCl melt,they had no significant effect on the reduction potential of each other.The equilibrium potentials of Mg^(2+)/Mg and Al^(3+)/Al were obtained by open circuit potential method.Their apparent standard potentials were also calculated in this system and the values were-2.52 V vs Cl_(2)/Cl^(−),-1.66 V vs Cl_(2)/Cl^(−),respectively.Correspondingly,the apparent Gibbs free energies of Mg^(2+)/Mg and Al^(3+)/Al were-485.71 kJ/mol^(-1),-480.78 kJ/mol^(-1).Finally,potentiostatic electrolysis was performed on a Mo electrode in LiCl-KCl-MgCl_(2)-AlCl_(3)(the mass ratio of MgCl_(2) to AlCl_(3) was 10:1)melt at different potentials.The components of the deposits were characterized by scanning electron microscope and energy dispersive spectroscopy.The study revealed that the content of Al in the deposit decreased as the overpotential increased and Al tended to segregate at the grain boundaries.
文摘The electroplating behavior of Zn P alloy on copper from light acid chloride solutions (LACS) was investigated using cyclic voltammetry and linear potential sweep method. It is found that, under the experimental conditions, the concentrations of H 3PO 3 and ascorbic acid in LACS change the codeposition mechanism of Zn P alloy, the addition of H 3PO 3 into LACS promotes the three dimentional (3 D) instantaneous nucleation/growth, while the addition of ascorbic acid promotes the two dimentional (2 D) instantaneous nucleation and layer by layer growth. H 3PO 3 and zinc ions inhibit the deposition each other. The experimental results also show that H 3PO 3 in the LACS can be reduced on the cathode individually, and low pH value of the LACS promotes the reduction of H 3PO 3.
基金Project supported by 2015 Shandong Provincal Fund for Outstanding Talent Group,China
文摘An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction(XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl_2 film due to Cl ions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg_(17)Al_(12) phase containing experimental alloys. The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg_2 Pb and Mg_(17)Al_(12) somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.
文摘This investigation describes the one step preparation of potassium carbonate by electrolysis of potas-sium chloride solution in electrolyzers with various Nation membranes.Potassium bicarbonate solution wasfed to the cathode compartment,where it was converted into carbonate by reaction with the hydroxideformed at cathode.Because of the low OH^- concentration in the cathode compartment,the back migrationof OH^- through the membrane was almost negligible,resulting in a higher current efficiency,say 90% or more.In this study,electroconductivity,mass transfer,current efficiency and cell voltage were measured.Thefeasibility of the process was discussed and the optimal conditions examined.
基金Supported by the Science&Technology Department of Jilin Province (Grant Nos.20180101199JC and 20180101204JC)Jilin Province/Jilin University Co-construction Project-Funds for New Materials (SXGJSF2017-3)。
文摘The V_2C compound,belonging to the group of two-dimensional transition metal carbonitrides,or MXenes,has demonstrated a promising electrochemical performance in capacitor applications in acidic electrolytes;however,there is evidence to suggest that V_2C is unstable in an acidic environment.On the other hand,the performance of V_2C in neutral aqueous electrolytes is still moderate,and has not yet been systematically studied.The charge storage mechanism in a V_2C electrode,employed in neutral aqueous electrolytes,is investigated via cyclic voltammetry testing and in situ x-ray diffraction(XRD).Good specific capacitances are achieved,specifically208 F/g in 0.5 M Li_2SO_4,225 F/g in 1 M MgSO_4,120 F/g in 1 M Na_2 SO_4,and 104 F/g in 0.5 M K_2SO_4.Using in situ XRD,we observe that,during the charge and discharge process,the c-lattice parameter shrinks or expands by up to 0.25 A in MgSO_4,and 0.29 A in Li_2SO_4 which demonstrates the intercalation/de-intercalation of cations into the d-V_2C layer.
基金financially sponsored by the National Basic Research Program of China(2014CB643306)
文摘The effect of solution pH,Cl^- concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscopy and X-ray photoelectron spectroscopy.The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0,below which the anodic polarization curves of the steel are actively dissolved.The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl^- concentration and solution temperature.Pits are initiated on the sample surface in the presence of the Cl^- and gradually developed into uniform corrosion with increasing the Cl^- concentrations.Moreover,the corrosion is more serious with an increase in solution temperature.
基金funded by the National Natural Science Foundation of China(No.51805259)the National Natural Science Foundation of China for Creative Research Groups(No.51921003)+3 种基金the Natural Science Foundation of Jiangsu Province,China(Nos.BK20180431 and BK20190419)China Postdoctoral Science Foundation(Nos.2019M661833 and 2018M642246)Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology,Chinathe Young Elite Scientists Sponsorship Program by CAST,China。
文摘Titanium alloy plays a crucial role in the electrochemical field due to its excellent corrosion resistance.The passivation and dissolution behaviors of Ti-6.5Al-2Zr-1Mo-1V(TA15)alloy in Na Cl solution were studied by simulating the electrochemical machining process in a rotating condition,which made the anode in a state with alternating high and low current density.Electron probe micro analysis,ultra-depth microscope,scanning electron microscope,and X-ray photoelectron spectrometer were used to reveal the evolution of TA15 under fluctuating current density.The existence state of the passivation film on TA15 surface was closely related to the pulse frequency of the periodically fluctuating current density.At higher pulse frequency of 0.20 Hz,the material was hardly dissolved because passivation dominated the electrolysis behavior,while at lower pulse frequency of 0.01 Hz,the passivation and dissolution behaviors occurred alternately with the variation of the current density.Herein,the thickness of the passivation film was inversely proportional to the applied current density.Due to the different electrochemical characteristics of a phase andβphase,the surface of the TA15 changed from being smooth to porous after a period.In addition,the change of microstructure affected the content of O^(2–)and exposed the suboxides of titanium.In a word,the change of pulse frequency and current density affected the electrochemical behavior of TA15,which was different from the conventional steady condition.
文摘The electrochemical behaviors and corrosion resistance of the wrought Mg–Y–Zn based alloys with high Y/Zn mole ratio have been investigated in details.The results show that the corrosion resistance of the investigated Mg–Y–Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios.Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates,but also leads to the precipitation of Mg_(24)Y_(5) phase.The corrosion rate of Mg–Y–Zn based alloys greatly increases from 7.4 mg·cm^(−2)·day^(−1) to 11.3 mg·cm^(−2)·day^(−1) with increasing the Y/Zn mole ratio up to 3.It should be attributed to the decreasing size of LPSO phase plates as cathodes,further increasing the hydrogen evolution kinetics.The related corrosion mechanism is discussed in details.
基金This study is funded by the Assistant Secretary for Energy Efficiency,Vehicle Technologies Office of the U.S.Department of Energy,under the Si Consortium Program.Electron microscopy experiments are conducted at the National Centre for Electron Microscopy and the Molecular Foundry located at Lawrence Berkeley National Laboratory is supported by the Director,Office of Science,Office of Basic Energy Sciences,the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘To address the issues of large volume change and low conductivity of silicon(Si)materials,carbon coatings have been widely employed as surface protection agent and conductive medium to encapsulate the Si materials,which can improve the electrochemical performance of Si-based electrodes.There has been a strong demand to gain a deeper understanding of the impact of efficient carbon coating over the lithiation and delithiation process of Si materials.Here,we report the first observation of the extended two-phase transformation of carbon-coated Si nanoparticles(Si/C)during electrochemical processes.The Si/C nanoparticles were prepared by sintering Si nanoparticles with polyvinylidene chloride precursor.The Si/C electrode underwent a two-phase transition during the first 20 cycles at 0.2 C,but started to engage in solid solution reaction when the ordered compact carbon coating began to crack.Under higher current density conditions,the electrode was also found to be involved in solid solution reaction,which,however,was due to the overwhelming demand of kinetic property rather than the breaking of the carbon coating.In comparison,the Si/C composites prepared with sucrose possessed more disordered and porous carbon structures,and presented solid solution reaction throughout the entire cycling process.
文摘Azaperone,with anti-anxiety and anti-aggressive activities used in veterinary medicine,is a member of the butyrophenone class.It is ordinarily utilized for a wide range of indications,such as sedation,obstetrics,and anesthesia.In this research,an improved synthetic route is presented for azaperone using a phase-transfer catalyst(PTC).In general,it was synthesized as a dopamine antagonist in four steps.The bis(2-chloroethyl)amine intermediate is easily obtained after the conversion of the alcohol groups into the chloride leaving group using thionyl chloride(95%yields).The alkylation of commercially available 2-amino pyridine in the presence of PTC was then carried out,giving 1-(pyridin-2-yl)piperazine with 75%yield.1-(Pyridin-2-yl)piperazine was finally alkylated using 4-chloro-1-(4-fluorophenyl)butan-1-one to achieve azaperone with 60%yield.The butyrophenone intermediate was obtained via the Friedel-Crafts reaction of fluorobenzene with 4-chlorobutyryl chloride in the presence of AlCl3.High efficiency,gentle reaction conditions,and fast and simple procedure are the advantages of this method.Also,the electrochemical oxidation behaviour of azaperone was investigated using cyclic and differential pulse voltammetry techniques.Cyclic voltammetric studies indicated an irreversible process for azaperone electro-oxidation with a peak potential of 0.78 V in a phosphate buffer solution(pH=7.0)vs.Ag/AgCl(saturated KCl)electrode.The value of the peak current vs.the azaperone concentration was enhanced linearly in the range of 10―70μmol/L,and the detection limit was found to be 3.33μmol/L.
基金financially supported by the National Research Laboratory Project of the National Research Foundation funded by the Ministry of Science and ICT,Republic of Korea(NRF-2020R1A2C2004192)G.Y.H.for research support via the YGY Project(YGY20150627000)supported by National Research Foundation(NRF)of South Korea(2022R1A2C1004392)。
文摘Heterocyclic compounds are the promising biological compounds as nature-friendly for the corrosion protection of metallic surface.In this work,three heterocyclic compounds such as 1-azanaphthalene-8-ol(8-AN),2-methylquinoline-8-ol(8-MQ),and 8-quinolinol-5-sulfonic acid(8-QSA)were used as green compounds,and their anti-corrosion performance for AZ31 Mg in saline water was discussed on the basis of impedance interpretation and surface analysis.Findings found that the electrochemical performance was improved in the order of 8-AN>8-MQ>8-QSA,demonstrating the electron donor effect of N-heterocycles to form coordination complexes on the magnesium surface.From the electrochemical performance,the protective layer constructed at the optimal concentration reinforces the barrier against aggressive environments,with potential inhibition efficiency of 87.4%,99.0%,and 99.9%for 8-QSA,8-MQ,and 8-AN,respectively.Quantum chemical parameters and electron density distribution for free organic species in the absence and presence of Mg^(2+)cation were evaluated using density functional theory(DFT).Upon the formation of coordination complexes between organic compound and Mg^(2+),energy gap underwent change about ΔE=5.7 eV in the 8-AN/Mg^(2+)system.Furthermore,the adsorption of heterocyclic compounds on Mg surface reveals the formation of strong covalent bonds with Mg atoms,which further confirmed by the electron density difference and projected density of states analyses.Based on theoretical calculations,three inhibitors can adsorb on the metal surface in both parallel and perpendicular orientations via C,O and N atoms.In the parallel configuration,the C-Mg,N-Mg and O-Mg bond distances are between 2.11 and 2.25˚A,whereas the distances in the case of perpendicular adsorption are between 2.20 and 2.40˚A(covalent bonds via O and N atoms).The results indicated that parallel configurations are energetically more stable,in which the adsorption energies are-4.48 eV(8-AN),-4.28 eV(8-MQ)and-3.82 eV(8-QSA)compared to that of perpendicular adsorption(-3.65,-3.40,and-2.63 eV).As a result,experimental and theoretical studies were in well agreement and confirm that the nitrogen and oxygen atoms will be the main adsorption sites.
基金Project(IRT_14R48)supported by the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of ChinaProjects(51271158,51272158,51401175,51504213)supported by the National Natural Science Foundation of China+2 种基金Project([2009]17)supported by the Changjiang Scholar Incentive Program,ChinaProject(CX2015B224)supported by the Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2015WK3021)supported by the Hunan Provincial Key Research Program,China
文摘Porous Al-Mg alloys with different nominal compositions were successfully fabricated via elemental powder reactive synthesis, and the phase composition, pore structure, and corrosion resistance were characterized with X-ray diffractometer, scanning electron microscope and electrochemical analyzer. The volume expansion ratio, open porosity and corrosion resistance in 3.5%(mass fraction) Na Cl aqueous solution of the alloys increase at first and then decrease with the increase of Mg content. The maxima of volume expansion ratio and open porosity are 18.3% and 28.1% for the porous Al-56%Mg(mass fraction) alloy, while there is the best corrosion resistance for the porous Al-37.5% Mg(mass fraction) alloy. The pore formation mechanism can be explained by Kirkendall effect, and the corrosion resistance can be mainly affected by the phase composition for the porous Al-Mg alloys. They would be of the potential application for filtration in the chloride environment.
文摘The semiconductive characteristics of clectron-transfrring proteins in living cells E coli was investigated by electrochemsical impedance spectroscopy(EIS). We found that the electrochemical impedance of living cells as a function of temprature followed the Arrhenius equation for semiconductors. This result shows a strong evidence to prove the semiconductive behavior of
基金supported by the National Natural Science Foundation of China(Grant Nos.:51901153)Shanxi Scholarship Council of China(Grant No.:2019032)+1 种基金Natural Science Foundation of Shanxi(Grant No.:202103021224049)the Science and Technology Major Project of Shanxi Province(Grant No.:20191102008,20191102007)。
文摘The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are evaluated.The grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing alloy.Note that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing alloy.The electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical activity.Using In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca alloying.The micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly improved.The In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.
基金supported by the Joint Program of the National Natural Science Foundation of China(U1808216)the National Natural Science Foundation of China(Grant No.52275331)+2 种基金the Key Research and Development Program of Hubei Province(No.2022BAA011)the Academic Frontier Youth Team(2018QYTD04)at Huazhong University of Science and Technology(HUST)the Laboratory Project of Science and Technology on Power Beam Processes Laboratory and the Hong Kong Scholars Program(No.XJ2022014).
文摘The porous metallic biomaterials have attracted significant attention for implants because their lower young's modulus matches the human bones, which can eliminate the stress shielding effect and facilitate the growth of bone tissue cells. The porous metallic biomaterials fabricated by selective laser melting (SLM) have broad prospects, but the surface of the SLM-built porous structure has been severely adhered with unmelted powders, which affects the forming accuracy and surface quality. The porous metallic biomaterials face the corrosion problem of complex body fluid environments during service, so their corrosion resistance in the human body is extremely important. The surface quality will affect the corrosion resistance of the porous metallic biomaterials. Therefore, it is necessary to study the effect of post-treatment on the corrosion resistance of SLMed samples. In this work, the mechanical response and the electrochemical corrosion behavior in simulated body fluid of diamond and pentamode metamaterials Ti-6Al-4V alloy fabricated by SLM before and after sandblasting were studied. After sandblasting, the mechanical properties of the two porous metallic biomaterials were slightly improved, and the self-corrosion potential and pitting potential were more negative;meanwhile, the self-corrosion current density and passive current density increased, indicating that its corrosion performance decreased, and the passive film stability of sandblasted samples got worse.
基金financially supported by the Fundamental Research Funds of Shangdong University(2016JC005,2017JC042,2017JC010)High-level Talents’Discipline Construction Fund of Shandong University(31370089963078)+1 种基金Technology Major Project(2017CXGC1010,2018JMRH0211,ZR2017MEM002)School research startup expenses of Harbin Institute of Technology(Shenzhen)(DD29100027)。
文摘For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nanorods were prepared by facile high-temperature solid-state reaction.The as-prepared materials were well studied and they show outstanding electrochemical behavior.We assembled hybrid supercapacitors with commercial activated carbon(YEC-8 A)as anode and K1.04Mn8 O16 as cathode.It shows high energy and power densities.Li-ion capacitors reach a high energy density of 127.61 Wh kg-1 at the power density of 99.86 W kg-1 and Na-ion capacitor obtains 170.96 Wh kg-1 at 133.79 W kg-1.In addition,the hybrid supercapacitors demonstrate excellent cycling performance which maintain 97%capacitance retention for Li-ion capacitor and 85%for Na-ion capacitor after 10,000 cycles.
基金financially supported by the National Natural Science Foundation of China(No.51874222).
文摘Composite electrodes prepared by cation exchange resins and activated carbon(AC)were used to adsorb Ⅴ(Ⅳ)in capacitive deionization(CDI).The electrode made of middle resin size(D860/AC M)had the largest specific surface area and mesoporous content than two other composite electrodes.Electrochemical analysis showed that D860/AC M presents higher specific capacitance and electrical double layer capacitor than the others,and significantly lower internal diffusion impedance.Thus,D860/AC M exhibits the highest adsorption capacity and rate of Ⅴ(Ⅳ)among three electrodes.The intra-particle diffusion model fits well in the initial adsorption stage,while the liquid film diffusion model is more suitable for fitting at the later stage.The pseudo-second-order kinetic model is suited for the entire adsorption process.The adsorption of Ⅴ(Ⅳ)on the composite electrode follows that of the Freundlich isotherm.Thermodynamic analysis indicates that the adsorption of Ⅴ(Ⅳ)is an exothermic process with entropy reduction,and the electric field force plays a dominant role in the CDI process.This work aims to improve our understanding of the ion adsorption behaviors and mechanisms on the composite electrodes in CDI.
