Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,t...Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,traditional setup needs an external unit for flow anode material separation and recovery,which inevitably increases the capital cost and hinders its continuous operation.Herein,a specific porous cathode is introduced to achieve continuous water purification with high contaminant removal in a flow anodic oxidation system.The efuent concentration of carbamazepine(CBZ),a common and model contaminant widely detected in natural water environment,was reduced by 99%.The linear sweep voltammetry(LSV)and quenching tests demonstrated that HO·was the dominant reactive species.While the removal of contaminants was inhibited in practical surface water,largely related to the quenching by dissolved organic matter and bicarbonate,the flow anodic oxidation process was competent in alleviating the ecotoxicity following oxidation.Our study constructs a modular device for cost-effective continuous water purification and provides insight into the mechanisms of flow andic oxidation.展开更多
The effect of different intermediate annealing heat treatments on the surface microstructures and anodic oxide film structures of rolled Al-5.6Mg sheets was studied.The results show that when the continuous annealing ...The effect of different intermediate annealing heat treatments on the surface microstructures and anodic oxide film structures of rolled Al-5.6Mg sheets was studied.The results show that when the continuous annealing is used to control microstructures of the sheets instead of the static state annealing in the intermediate annealing process,the surface grain size of the sheets can be reduced by about 65.7%,and the size of the Mg precipitation phase(Mg_(2)Al_(3))can be reduced by about 67%.Under the combined influence of grain size,precipitation phase,and texture,the highest glossiness can be obtained,which is attributed to continuous intermediate annealing and stabilization annealing at low temperature.The uniform grain and precipitation structures is beneficial to reducing the inhomogeneous dissolution of the oxide film and to obtain the anodic oxide film with uniform thickness and high glossiness.展开更多
This study exhibits a design of the discharge product film of a bulk AZ63-Ce-La-Ca(AZ63X)anode for Mg-air battery.An ideal discharge product film for Mg anode is that it could inhibit the anodic hydrogen evolution but...This study exhibits a design of the discharge product film of a bulk AZ63-Ce-La-Ca(AZ63X)anode for Mg-air battery.An ideal discharge product film for Mg anode is that it could inhibit the anodic hydrogen evolution but does not hinder the transfer of the electrons at the interface.Fortunately,the addition of Ce,La,and Ca into AZ63 alloy achieves this goal.The Mg-air battery with AZ63X anode in 3.5%Na Cl has an ultrahigh anodic efficiency of 85.7±1.7%and energy-density of 2431±53 mWh g^(-1)with the unique discharge product film,surpassing the values of most reported Mg-air batteries.Furthermore,the alloying elements reduce the anode delamination effect significantly by transforming the block Mg_(17)Al_(12)phase into the connected Mg_(17)Al_(12)structure and fine rod Al_(2)RE and Al_(2)Ca.展开更多
Owing to the advantages of simple structure,low power consumption and high-density integration,memristors or memristive devices are attracting increasing attention in the fields such as next generation non-volatile me...Owing to the advantages of simple structure,low power consumption and high-density integration,memristors or memristive devices are attracting increasing attention in the fields such as next generation non-volatile memories,neuromorphic computation and data encryption.However,the deposition of memristive films often requires expensive equipment,strict vacuum conditions,high energy consumption,and extended processing times.In contrast,electrochemical anodizing can produce metal oxide films quickly(e.g.10 s) under ambient conditions.By means of the anodizing technique,oxide films,oxide nanotubes,nanowires and nanodots can be fabricated to prepare memristors.Oxide film thickness,nanostructures,defect concentrations,etc,can be varied to regulate device performances by adjusting oxidation parameters such as voltage,current and time.Thus memristors fabricated by the anodic oxidation technique can achieve high device consistency,low variation,and ultrahigh yield rate.This article provides a comprehensive review of the research progress in the field of anodic oxidation assisted fabrication of memristors.Firstly,the principle of anodic oxidation is introduced;then,different types of memristors produced by anodic oxidation and their applications are presented;finally,features and challenges of anodic oxidation for memristor production are elaborated.展开更多
Constant-current anodization of pure aluminum was carried out in non-corrosive capacitor working electrolytes to study the formation mechanism of nanopores in the anodic oxide films.Through comparative experiments,nan...Constant-current anodization of pure aluminum was carried out in non-corrosive capacitor working electrolytes to study the formation mechanism of nanopores in the anodic oxide films.Through comparative experiments,nanopores are found in the anodic films formed in the electrolytes after high-temperature storage(HTS)at 130°C for 240 h.A comparison of the voltage-time curves suggests that the formation of nanopores results from the decrease in formation efficiency of anodic oxide films rather than the corrosion of the electrolytes.FT-IR and UV spectra analysis shows that carboxylate and ethylene glycol in electrolytes can easily react by esterification at high temperatures.Combining the electronic current theory and oxygen bubble mold effect,the change in electrolyte composition could increase the electronic current in the anodizing process.The electronic current decreases the formation efficiency of anodic oxide films,and oxygen bubbles accompanying electronic current lead to the formation of nanopores in the dense films.The continuous electronic current and oxygen bubbles are the prerequisites for the formation of porous anodic oxides rather than the traditional field-assisted dissolution model.展开更多
This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/...This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/submicro-pores and internal cavities,which is conducive to the adhesion and growth of bone cells.After AE treatment,with increase of the Cu content in the alloy,the surface of Ti-Cu alloy became sharper,with more fine micropores and internal cavities,thus increasing the surface area.The results indicated that the AE/Ti-Cu alloy exhibited good antibacterial properties and had the effect of inhibiting bacterial biofilm formation.AE treatment could increase the Cu ions release of Ti-Cu alloy in saline,and the higher the Cu content in the alloy,the more Cu ions release,resulting in stronger antibacterial performance of the alloy.AE/Ti-Cu alloy showed excellent biocompatibility,similar to the pure Ti.Therefore,anodic etching is a safe and effective surface treatment method for Ti-Cu alloy,with good clinical application prospects.展开更多
Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,t...Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.展开更多
The special experimental device and sulfuric acid electrolyte were adopted to study the influence of anodic oxidation heat on hard anodic film for 2024 aluminum alloy. Compared with the oxidation heat transferred to t...The special experimental device and sulfuric acid electrolyte were adopted to study the influence of anodic oxidation heat on hard anodic film for 2024 aluminum alloy. Compared with the oxidation heat transferred to the electrolyte through anodic film, the heat transferred to the coolant through aluminum substrate is more beneficial to the growth of anodic film. The film forming speed, film thickness, density and hardness are significantly increased as the degree of undercooling of the coolant increases. The degree of undercooling of the coolant, which is necessary for the growth of anodic film, is related to the degree of undercooling of the electrolyte, thickness of aluminum substrate, thickness of anodic film, natural parameters of bubble covering and current density. The microstructure and performance of the oxidation film could be controlled by the temperature of the coolant.展开更多
The formation mechanism of porous anodic oxides remains unclear till now.The classical field-assisted dissolution(FAD)theory cannot explain the relationship between the current curve and FAD reaction,and the influence...The formation mechanism of porous anodic oxides remains unclear till now.The classical field-assisted dissolution(FAD)theory cannot explain the relationship between the current curve and FAD reaction,and the influence of the electrode potential on anodization is rarely reported.The electrode potential theory,oxygen bubble model and the ionic current and electronic current theories were introduced to explain the growth of porous anodic oxides of three metals(Ti,Zr and Fe).Taking the anodization of Ti in aqueous solution containing 0.5wt% NH_(4)F as an example,the electrode potential was calculated,and the morphology of porous anodic oxides was investigated at low voltages.Results show that the growth of porous anodic oxides is determined by the ratio of the ionic current to the electronic current.During the anodization,metals are classified into two groups:one is easy to form the compact oxide layer,and the other is easy to induce oxygen releasing,thus forming oxygen bubbles.The electrolyte is also classified into two groups correspondingly:compact oxide layer-assisted electrolyte and releasing oxygen-assisted electrolyte.展开更多
Covalent organic frameworks(COFs)after undergoing the superlithiation process promise high-capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox-active sites.Here...Covalent organic frameworks(COFs)after undergoing the superlithiation process promise high-capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox-active sites.Herein,integrating carbon nanotubes(CNTs)with imine-linked covalent organic frameworks(COFs)was rationally executed by in-situ Schiff-base condensation between 1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde and 1,4-diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites(CNT@COF).Accordingly,the redox-active shell of COF nanoparticles around one-dimensional conductive CNTs synergistically creates robust three-dimensional hybrid architectures with high specific surface area,thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode.Remarkably,upon the full activation with a superlithiation process,the as-fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g^(−1),which is the highest specific capacity among organic electrode materials reported so far.Meanwhile,the superior rate capability and excellent cycling stability are also obtained.The redox reaction mechanisms for the COF moiety were further revealed by Fourier-transform infrared spectroscopy in conjunction with X-ray photoelectron spectroscopy,involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs.展开更多
Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesi...Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.展开更多
The microstructure and corrosion resistance of different boric/sulfuric acid anodic（BSAA） films on 7050 aluminum alloy were studied by atomic force microscopy（AFM）,electrochemical impedance spectroscopy（EIS） and...The microstructure and corrosion resistance of different boric/sulfuric acid anodic（BSAA） films on 7050 aluminum alloy were studied by atomic force microscopy（AFM）,electrochemical impedance spectroscopy（EIS） and scanning Kelvin probe（SKP）.The results show that boric acid does not change the structure of barrier layer of anodic film,but will significantly affect the structure of porous layer,consequently affect the corrosion resistance of anodic film.As the content of boric acid in electrolyte increases from 0 to 8 g/L,the resistance of porous layer（Rp） of BSAA film increases,the capacitance of porous layer（CPEp） decreases,the surface potential moves positively,the pore size lessens,and the corrosion resistance improves.However,the Rp,CPEp and surface potential will change towards opposite direction when the content of boric acid is over 8 g/L.展开更多
The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） a...The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, respectively. The corrosion resistance was evaluated by electrochemical impedance spectroscopy （EIS）. The results showed that the adipic acid was absorbed at the electrolyte/anodic layer interface during anodizing. The corrosion rate of anodic film decreased and the film thickness increased. The film was uniform and compact especially at the film/substrate interface. After sealing procedure, anodic film formed with the addition of adipic acid exhibited improved dielectric property and corrosion resistance in aggressive environment.展开更多
Anodic bonding between silicon and glass with dou bl e electric fields is presented.By this means,the damage caused by the electric f ield to the movable part during bonding can be avoided and the experiment result s ...Anodic bonding between silicon and glass with dou bl e electric fields is presented.By this means,the damage caused by the electric f ield to the movable part during bonding can be avoided and the experiment result s show that.展开更多
Boron-doped diamond （BDD） electrocatalysis is combined with photocatalysis using titanium dioxide （TiO2） as a catalyst to improve pollutant-oxidation efficiency. Phenol solution is chosen as model wastewater. Diff...Boron-doped diamond （BDD） electrocatalysis is combined with photocatalysis using titanium dioxide （TiO2） as a catalyst to improve pollutant-oxidation efficiency. Phenol solution is chosen as model wastewater. Different methods involving BDD and/or TiO2 during the degradation processes are compared. Parameters such as the currency density and initial concentration are varied in order to determine their effects on the oxidation process. Moreover, the degradation kinetics of phenol is experimentally studied. The results reveal the superiority of series combination of BDD and TiO2, especially the treatment process of electrocatalysis and succedent photocatalysis, and the optimum working currency density for electrocatalysis is 25.48 mA/cm2. The removal rate decreases with the increase in the initial phenol concentration and the degradation reaction follows quasi-first-order kinetics equation.展开更多
Anodic dissolutionbehaviorof zirconium inBu^n 4NBr-contaningisopropanol solution was investigated using cyclic voltammetry, linear sweep voltammetry and chronoamperometry, complemented with a scanning electron microsc...Anodic dissolutionbehaviorof zirconium inBu^n 4NBr-contaningisopropanol solution was investigated using cyclic voltammetry, linear sweep voltammetry and chronoamperometry, complemented with a scanning electron microscope （SEM）.The voltammograms did not exhibit active dissolutionuntil the breakdown of passive layer induced by aggressive bromide anions.SEM images confirmed the existence of pits on zirconium surface.The depth and breadth of pits were intensified with increasing potential. The pitting potentialshifted negatively as either temperature orBu^n 4NBr concentration was increased, while it increased with increasing scan rate.The corrosion current density increased with increasing temperature. The apparent activation energyof anodic dissolutionofzirconiumwas 21.88kJ/mol. The chronoamperometry revealed that increasingBu^n 4NBrconcentration shortened the incubation time for passivity breakdown and accelerated the pit nucleation and growth. The experimental results were helpfulto obtain the optimum conditions for electrosynthesis of zirconium isopropoxide.展开更多
A self-ordered porous film was fabricated on aluminum alloy in a ternary boric-sulfuric-oxalic acid electrolyte system. By means of voltage–time response, the oxidation process as well as the growth efficiency was st...A self-ordered porous film was fabricated on aluminum alloy in a ternary boric-sulfuric-oxalic acid electrolyte system. By means of voltage–time response, the oxidation process as well as the growth efficiency was studied. Field emission scanning electron microscopy（FE-SEM） was adopted to reveal the morphological and microstructural features of as-fabricated oxide layers. The corrosion protection properties of the films were investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the concentration of the double ionic layer located at the oxide interface could accelerate the film growth rate. The anodic oxidative layer with thickness of 8-9 μm and pore diameter of 10-14 nm maintains the pattern and topography of workpieces, compared with the overall closed film with hierarchical structure. Both samples exhibited much lower corrosion current density after boil water sealing. Meanwhile, a superior stability could be achieved through raising the ambient temperature.展开更多
The effect of the microstructure of an Al 7050-T7451 substrate on the anodic oxide formation in sulfuric acid was studied in this article. The microstructure of the substrate was assessed by optical microscope （OM） ...The effect of the microstructure of an Al 7050-T7451 substrate on the anodic oxide formation in sulfuric acid was studied in this article. The microstructure of the substrate was assessed by optical microscope （OM） and transmission electron microscope （TEM）. The surface and cross-section morphologies of the oxide films were examined by scanning electron microscope （SEM）. The chemical composition of intermetallic particles in the alloys and films was investigated using energy dispersive spectroscope （EDS）. The roles of intermetallic phases and grain or subgrain boundaries on the oxide film formation were researched using the potentiodynamic and potentiostatic polarization technique in sulfuric acid solution. The results show that the transition of coarse intermetallic particles or grain （subgrain） boundaries at the surface of Al alloys can be characterized by potentiodynamic polarization curves. The surface and cross-section micrographs of the anodic layer seem to preserve the microstructure of the substrate. Large cavities in the anodic films are caused by the preferential dissolution of coarse AItCuMg particles and the entrance of Cu-rich remnants into the electrolyte during anodizing. The Al7Cu2Fe particles tend to be occluded in the oxide layer or lose from the oxide surface because of peripheral trenching. Small pores in the films are induced by the dissolution of precipitates in grain or subgrain boundaries. The film surface of recrystallized grain bodies is smooth and homogeneous.展开更多
One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition o...One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition of water improved the current efficiency for the electrosynthesis of phenyl acetate. The maximum efficiency reached 4.8% with the selectivity of 96% to phenyl acetate when the electrolysis was carried out under the optimal conditions. The investigation also indicated that the concentration of phenyl acetate increased linearly in 12 h and reached 1.07 g/L with the selectivity of 95%. Cyclic voltammetry experiments showed that the adsorption of benzene at Pt anode enhanced by the addition of water was critical to the formation of phenyl acetate. An activated benzene mechanism was proposed for the anodic acytoxylation, and the analysis of gas products demonstrated that Kolbe reaction was the main side reaction.展开更多
Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered in- termetallic particles were examined by scanning electron microscopy （SEM） and energy dis...Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered in- termetallic particles were examined by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） after pretreatment. The anodic film was investigated by transmission electron microscopy （TEM）, and its corrosion resistance was analyzed by electrochemical impedance spectroscopy （EIS） and Tafel polarization in NaC1 solution. The results show that the size of A1-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the an- odic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.展开更多
基金financially supported by the Basic Science Center Project of the National Natural Science Foundation of China(No.52388101)Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08L213)the National Natural Science Foundation of China(No.52100030)。
文摘Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,traditional setup needs an external unit for flow anode material separation and recovery,which inevitably increases the capital cost and hinders its continuous operation.Herein,a specific porous cathode is introduced to achieve continuous water purification with high contaminant removal in a flow anodic oxidation system.The efuent concentration of carbamazepine(CBZ),a common and model contaminant widely detected in natural water environment,was reduced by 99%.The linear sweep voltammetry(LSV)and quenching tests demonstrated that HO·was the dominant reactive species.While the removal of contaminants was inhibited in practical surface water,largely related to the quenching by dissolved organic matter and bicarbonate,the flow anodic oxidation process was competent in alleviating the ecotoxicity following oxidation.Our study constructs a modular device for cost-effective continuous water purification and provides insight into the mechanisms of flow andic oxidation.
文摘The effect of different intermediate annealing heat treatments on the surface microstructures and anodic oxide film structures of rolled Al-5.6Mg sheets was studied.The results show that when the continuous annealing is used to control microstructures of the sheets instead of the static state annealing in the intermediate annealing process,the surface grain size of the sheets can be reduced by about 65.7%,and the size of the Mg precipitation phase(Mg_(2)Al_(3))can be reduced by about 67%.Under the combined influence of grain size,precipitation phase,and texture,the highest glossiness can be obtained,which is attributed to continuous intermediate annealing and stabilization annealing at low temperature.The uniform grain and precipitation structures is beneficial to reducing the inhomogeneous dissolution of the oxide film and to obtain the anodic oxide film with uniform thickness and high glossiness.
基金supported by the National Natural Science Foundation of China(52471095)National Key Research and Development Program of China(Grant No.2023YFC2811404)Natural Science Foundation of Xiamen,China(No.3502Z20227015)。
文摘This study exhibits a design of the discharge product film of a bulk AZ63-Ce-La-Ca(AZ63X)anode for Mg-air battery.An ideal discharge product film for Mg anode is that it could inhibit the anodic hydrogen evolution but does not hinder the transfer of the electrons at the interface.Fortunately,the addition of Ce,La,and Ca into AZ63 alloy achieves this goal.The Mg-air battery with AZ63X anode in 3.5%Na Cl has an ultrahigh anodic efficiency of 85.7±1.7%and energy-density of 2431±53 mWh g^(-1)with the unique discharge product film,surpassing the values of most reported Mg-air batteries.Furthermore,the alloying elements reduce the anode delamination effect significantly by transforming the block Mg_(17)Al_(12)phase into the connected Mg_(17)Al_(12)structure and fine rod Al_(2)RE and Al_(2)Ca.
基金supported by the National Key Research and Development Program of China (Grant No.2018YFE0203802)Natural Science Foundation of Hubei Province, China (Grant No.2022CFA031)Dongguan Innovative Research Team Program (2020607101007)。
文摘Owing to the advantages of simple structure,low power consumption and high-density integration,memristors or memristive devices are attracting increasing attention in the fields such as next generation non-volatile memories,neuromorphic computation and data encryption.However,the deposition of memristive films often requires expensive equipment,strict vacuum conditions,high energy consumption,and extended processing times.In contrast,electrochemical anodizing can produce metal oxide films quickly(e.g.10 s) under ambient conditions.By means of the anodizing technique,oxide films,oxide nanotubes,nanowires and nanodots can be fabricated to prepare memristors.Oxide film thickness,nanostructures,defect concentrations,etc,can be varied to regulate device performances by adjusting oxidation parameters such as voltage,current and time.Thus memristors fabricated by the anodic oxidation technique can achieve high device consistency,low variation,and ultrahigh yield rate.This article provides a comprehensive review of the research progress in the field of anodic oxidation assisted fabrication of memristors.Firstly,the principle of anodic oxidation is introduced;then,different types of memristors produced by anodic oxidation and their applications are presented;finally,features and challenges of anodic oxidation for memristor production are elaborated.
基金financially supported by the National Natural Science Foundation of China(Nos.51777097,51577093)。
文摘Constant-current anodization of pure aluminum was carried out in non-corrosive capacitor working electrolytes to study the formation mechanism of nanopores in the anodic oxide films.Through comparative experiments,nanopores are found in the anodic films formed in the electrolytes after high-temperature storage(HTS)at 130°C for 240 h.A comparison of the voltage-time curves suggests that the formation of nanopores results from the decrease in formation efficiency of anodic oxide films rather than the corrosion of the electrolytes.FT-IR and UV spectra analysis shows that carboxylate and ethylene glycol in electrolytes can easily react by esterification at high temperatures.Combining the electronic current theory and oxygen bubble mold effect,the change in electrolyte composition could increase the electronic current in the anodizing process.The electronic current decreases the formation efficiency of anodic oxide films,and oxygen bubbles accompanying electronic current lead to the formation of nanopores in the dense films.The continuous electronic current and oxygen bubbles are the prerequisites for the formation of porous anodic oxides rather than the traditional field-assisted dissolution model.
基金financially supported by the Natural Science Foundation of Liaoning Province(No.2022-MS-079).
文摘This study used an anodic etching(AE)method to construct a hierarchical rough surface on the surface of the Cu-bearing antibacterial titanium alloy,Ti-xCu(x=3,5,7 wt%),a three-dimensional structure with nested micro-/submicro-pores and internal cavities,which is conducive to the adhesion and growth of bone cells.After AE treatment,with increase of the Cu content in the alloy,the surface of Ti-Cu alloy became sharper,with more fine micropores and internal cavities,thus increasing the surface area.The results indicated that the AE/Ti-Cu alloy exhibited good antibacterial properties and had the effect of inhibiting bacterial biofilm formation.AE treatment could increase the Cu ions release of Ti-Cu alloy in saline,and the higher the Cu content in the alloy,the more Cu ions release,resulting in stronger antibacterial performance of the alloy.AE/Ti-Cu alloy showed excellent biocompatibility,similar to the pure Ti.Therefore,anodic etching is a safe and effective surface treatment method for Ti-Cu alloy,with good clinical application prospects.
基金Zhenjiang City Key R&D Plan Modern Agriculture Project(No.SH2021017)Zhenjiang“Jinshan Talents”Project 2021Jiangsu Province“Six Talent Peak”Program(No.XCL-111)。
文摘Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.
基金Project (SBZDPY-11-17) supported by the Fund on Key Laboratory Project for Hydrodynamic Force, Ministry of Education, China Project (SZD0502-09-0) supported by Key Disciplines of Materials Processing Engineering of Sichuan Province, China
文摘The special experimental device and sulfuric acid electrolyte were adopted to study the influence of anodic oxidation heat on hard anodic film for 2024 aluminum alloy. Compared with the oxidation heat transferred to the electrolyte through anodic film, the heat transferred to the coolant through aluminum substrate is more beneficial to the growth of anodic film. The film forming speed, film thickness, density and hardness are significantly increased as the degree of undercooling of the coolant increases. The degree of undercooling of the coolant, which is necessary for the growth of anodic film, is related to the degree of undercooling of the electrolyte, thickness of aluminum substrate, thickness of anodic film, natural parameters of bubble covering and current density. The microstructure and performance of the oxidation film could be controlled by the temperature of the coolant.
基金National Natural Science Foundation of China(51577093,51777097)Natural Science Foundation of Jiangsu Higher Education Institutions(20KJB430040)+1 种基金Changzhou Science&Technology Program(CJ20200026)Qing Lan Project in Colleges and Universities of Jiangsu Province。
文摘The formation mechanism of porous anodic oxides remains unclear till now.The classical field-assisted dissolution(FAD)theory cannot explain the relationship between the current curve and FAD reaction,and the influence of the electrode potential on anodization is rarely reported.The electrode potential theory,oxygen bubble model and the ionic current and electronic current theories were introduced to explain the growth of porous anodic oxides of three metals(Ti,Zr and Fe).Taking the anodization of Ti in aqueous solution containing 0.5wt% NH_(4)F as an example,the electrode potential was calculated,and the morphology of porous anodic oxides was investigated at low voltages.Results show that the growth of porous anodic oxides is determined by the ratio of the ionic current to the electronic current.During the anodization,metals are classified into two groups:one is easy to form the compact oxide layer,and the other is easy to induce oxygen releasing,thus forming oxygen bubbles.The electrolyte is also classified into two groups correspondingly:compact oxide layer-assisted electrolyte and releasing oxygen-assisted electrolyte.
基金supported by the National Natural Science Foundation of China(Grant No.52173091 and 52102300)the Program for Leading Talents of National Ethnic Affairs Commission of China(MZR21001)the Hubei Provincial Natural Science Foundation of China(2021CFA022).
文摘Covalent organic frameworks(COFs)after undergoing the superlithiation process promise high-capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox-active sites.Herein,integrating carbon nanotubes(CNTs)with imine-linked covalent organic frameworks(COFs)was rationally executed by in-situ Schiff-base condensation between 1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde and 1,4-diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites(CNT@COF).Accordingly,the redox-active shell of COF nanoparticles around one-dimensional conductive CNTs synergistically creates robust three-dimensional hybrid architectures with high specific surface area,thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode.Remarkably,upon the full activation with a superlithiation process,the as-fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g^(−1),which is the highest specific capacity among organic electrode materials reported so far.Meanwhile,the superior rate capability and excellent cycling stability are also obtained.The redox reaction mechanisms for the COF moiety were further revealed by Fourier-transform infrared spectroscopy in conjunction with X-ray photoelectron spectroscopy,involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs.
基金Project(42076043) supported by the National Natural Science Foundation of ChinaProject(ZR2023ZD31) supported by the Major Basic Research Project of Natural Science Foundation of Shandong Province,ChinaProject(2023VEA0007) supported by the Chinese Academy of Sciences President’s International Fellowship Initiative。
文摘Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.
文摘The microstructure and corrosion resistance of different boric/sulfuric acid anodic（BSAA） films on 7050 aluminum alloy were studied by atomic force microscopy（AFM）,electrochemical impedance spectroscopy（EIS） and scanning Kelvin probe（SKP）.The results show that boric acid does not change the structure of barrier layer of anodic film,but will significantly affect the structure of porous layer,consequently affect the corrosion resistance of anodic film.As the content of boric acid in electrolyte increases from 0 to 8 g/L,the resistance of porous layer（Rp） of BSAA film increases,the capacitance of porous layer（CPEp） decreases,the surface potential moves positively,the pore size lessens,and the corrosion resistance improves.However,the Rp,CPEp and surface potential will change towards opposite direction when the content of boric acid is over 8 g/L.
基金Project(51271012)supported by the National Natural Science Foundation of China
文摘The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, respectively. The corrosion resistance was evaluated by electrochemical impedance spectroscopy （EIS）. The results showed that the adipic acid was absorbed at the electrolyte/anodic layer interface during anodizing. The corrosion rate of anodic film decreased and the film thickness increased. The film was uniform and compact especially at the film/substrate interface. After sealing procedure, anodic film formed with the addition of adipic acid exhibited improved dielectric property and corrosion resistance in aggressive environment.
文摘Anodic bonding between silicon and glass with dou bl e electric fields is presented.By this means,the damage caused by the electric f ield to the movable part during bonding can be avoided and the experiment result s show that.
基金The Key Project of Chinese Ministry of Education (No.108601)Major Projects of National Water Pollution Control and Management Technology (No.2009ZX07101-011)Specialized Research Fund for the Doctoral Program of Higher Education (No.20060286010)
文摘Boron-doped diamond （BDD） electrocatalysis is combined with photocatalysis using titanium dioxide （TiO2） as a catalyst to improve pollutant-oxidation efficiency. Phenol solution is chosen as model wastewater. Different methods involving BDD and/or TiO2 during the degradation processes are compared. Parameters such as the currency density and initial concentration are varied in order to determine their effects on the oxidation process. Moreover, the degradation kinetics of phenol is experimentally studied. The results reveal the superiority of series combination of BDD and TiO2, especially the treatment process of electrocatalysis and succedent photocatalysis, and the optimum working currency density for electrocatalysis is 25.48 mA/cm2. The removal rate decreases with the increase in the initial phenol concentration and the degradation reaction follows quasi-first-order kinetics equation.
基金Project(51374254)supported by the National Natural Science Foundation of ChinaProject(2013JSJJ026)supported by the Teacher Research Foundation of Central South University,China
文摘Anodic dissolutionbehaviorof zirconium inBu^n 4NBr-contaningisopropanol solution was investigated using cyclic voltammetry, linear sweep voltammetry and chronoamperometry, complemented with a scanning electron microscope （SEM）.The voltammograms did not exhibit active dissolutionuntil the breakdown of passive layer induced by aggressive bromide anions.SEM images confirmed the existence of pits on zirconium surface.The depth and breadth of pits were intensified with increasing potential. The pitting potentialshifted negatively as either temperature orBu^n 4NBr concentration was increased, while it increased with increasing scan rate.The corrosion current density increased with increasing temperature. The apparent activation energyof anodic dissolutionofzirconiumwas 21.88kJ/mol. The chronoamperometry revealed that increasingBu^n 4NBrconcentration shortened the incubation time for passivity breakdown and accelerated the pit nucleation and growth. The experimental results were helpfulto obtain the optimum conditions for electrosynthesis of zirconium isopropoxide.
文摘A self-ordered porous film was fabricated on aluminum alloy in a ternary boric-sulfuric-oxalic acid electrolyte system. By means of voltage–time response, the oxidation process as well as the growth efficiency was studied. Field emission scanning electron microscopy（FE-SEM） was adopted to reveal the morphological and microstructural features of as-fabricated oxide layers. The corrosion protection properties of the films were investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the concentration of the double ionic layer located at the oxide interface could accelerate the film growth rate. The anodic oxidative layer with thickness of 8-9 μm and pore diameter of 10-14 nm maintains the pattern and topography of workpieces, compared with the overall closed film with hierarchical structure. Both samples exhibited much lower corrosion current density after boil water sealing. Meanwhile, a superior stability could be achieved through raising the ambient temperature.
文摘The effect of the microstructure of an Al 7050-T7451 substrate on the anodic oxide formation in sulfuric acid was studied in this article. The microstructure of the substrate was assessed by optical microscope （OM） and transmission electron microscope （TEM）. The surface and cross-section morphologies of the oxide films were examined by scanning electron microscope （SEM）. The chemical composition of intermetallic particles in the alloys and films was investigated using energy dispersive spectroscope （EDS）. The roles of intermetallic phases and grain or subgrain boundaries on the oxide film formation were researched using the potentiodynamic and potentiostatic polarization technique in sulfuric acid solution. The results show that the transition of coarse intermetallic particles or grain （subgrain） boundaries at the surface of Al alloys can be characterized by potentiodynamic polarization curves. The surface and cross-section micrographs of the anodic layer seem to preserve the microstructure of the substrate. Large cavities in the anodic films are caused by the preferential dissolution of coarse AItCuMg particles and the entrance of Cu-rich remnants into the electrolyte during anodizing. The Al7Cu2Fe particles tend to be occluded in the oxide layer or lose from the oxide surface because of peripheral trenching. Small pores in the films are induced by the dissolution of precipitates in grain or subgrain boundaries. The film surface of recrystallized grain bodies is smooth and homogeneous.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.21021001, No.20502017, and No.20872102）, and the Program for Changjiang Scholars and Innovative Research Team in University （No.0846）. The Analytic and Testing Center of Sichuan University are greatly appreciated.
文摘One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition of water improved the current efficiency for the electrosynthesis of phenyl acetate. The maximum efficiency reached 4.8% with the selectivity of 96% to phenyl acetate when the electrolysis was carried out under the optimal conditions. The investigation also indicated that the concentration of phenyl acetate increased linearly in 12 h and reached 1.07 g/L with the selectivity of 95%. Cyclic voltammetry experiments showed that the adsorption of benzene at Pt anode enhanced by the addition of water was critical to the formation of phenyl acetate. An activated benzene mechanism was proposed for the anodic acytoxylation, and the analysis of gas products demonstrated that Kolbe reaction was the main side reaction.
基金financially supported by the National Natural Science Foundation of China(No.51271012)
文摘Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered in- termetallic particles were examined by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） after pretreatment. The anodic film was investigated by transmission electron microscopy （TEM）, and its corrosion resistance was analyzed by electrochemical impedance spectroscopy （EIS） and Tafel polarization in NaC1 solution. The results show that the size of A1-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the an- odic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.
