Designing transition metal nickel-cobalt-based battery-type electrode materials driven by anions is crucial for achieving rapid OH-ion transport under electrochemical activation conditions,thereby improving capacitanc...Designing transition metal nickel-cobalt-based battery-type electrode materials driven by anions is crucial for achieving rapid OH-ion transport under electrochemical activation conditions,thereby improving capacitance performance.Herein,borate anions are selected through theoretical calculations,and twodimensional(2D)defect-rich amorphous nickel-cobalt-based borate is synthesized via a facile chemical reduction method.Under potentiostatic modification,activated products(NCB-G-E)are obtained.In situ Raman spectra reveal that electron-deficient borate extracts electrons from metal centers,facilitating the oxidation state transition of Ni and Co.Theoretical calculations show that in situ adsorbed borate regulates the d-band centers of metal sites,enhancing OH^(-)intermediate adsorption.Meanwhile,borate anion adsorption accelerates the deprotonation and activation processes.Electrochemical tests demonstrate that NCB-G-E displays superior capacitance performance,with a high quality specific capacity of383.3 mA h g^(-1)and 65% retention rate at 30 A g^(-1),surpassing most nickel-cobalt-based electrodes.The assembled asymmetric supercapacitor presents an impressive energy density of 68.2 Wh kg^(-1)and good cycling stability.This work highlights the role of electron-deficient borate in tuning metal band structure and promoting oxidation state transition through synergistic defect advantages,offering new prospects for advanced battery-type energy storage materials.展开更多
Anion modification has been considered as a strategy to improve water splitting efficiency upon oxygen evolution reaction(OER).However,constructing a novel catalysis system with high catalytic activity and precise str...Anion modification has been considered as a strategy to improve water splitting efficiency upon oxygen evolution reaction(OER).However,constructing a novel catalysis system with high catalytic activity and precise structures is still a huge challenge due to the tedious procedure of precursor synthesis and anion selection.Here,a bimetallic(FeNi)nanowire self-assembled superstructure was synthesized using the Hoffmann rearrangement method,and then functionalized with four anions(P,Se,S,and O).Notably,the Fe_(3)Se_(4)/Ni_(3)Se_(4) catalyst shows a high conductivity,enhances the adsorption of intermediate products,accelerates the rate-determining step,and consequently results to improved electrocatalytic performance.Using the Fe_(3)Se_(4)/Ni_(3)Se_(4) catalyst exhibits enhanced performance with overpotential of 316mV at 10 mA/cm^(2),in stark contrast to Fe_(2) P/Ni_(2)P(357mV),Fe_(7)S_(8)/NiS(379 mV),and Fe_(3)O_(4)/NiO(464 mV).Moreover,the formation mechanism of superstructure and the relationship between electronegativities and electrocatalytic properties,are elucidated.Accordingly,this work provides an efficient approach to Hoffmann-type coordination polymer catalyst for oxygen evolution towards a near future.展开更多
A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-lar...A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-larly crosses the master supersonic jet beam from a home-made pulsed piezo valve.The discharge nozzle is designed for high voltage gas discharge with efficient metal sputtering of the cathode,and thus plays a role in met-al atom and ion source.Supersonically jet-cooled anions can be produced in the master gas jet via reactions of the plasma products.The source is integrated into a photoelectron ve-locity imaging spectrometer.Test mass spectrometry experiments show that the ion source can efficiently produce transition metal containing anions,such as FeO_(m)^(-),CuO_(m)^(-),CuC_(n)^(-),CuC_(n)O_(m)^(-).The photoelectron imaging results by photodetachment of O-show that the pho-toelectron energy resolution of the whole instrument isΔE/E≈2.3%,and the results of FeO^(-)indicate that internal temperatures of anions from the source could be efficiently cooled down.展开更多
The development of efficient and robust anode materials for stable alkaline seawater electrolysis is severely limited by chlorine evolution reaction and chloride corrosion.Here,the sulfur-doped cobalt-nickel bimetalli...The development of efficient and robust anode materials for stable alkaline seawater electrolysis is severely limited by chlorine evolution reaction and chloride corrosion.Here,the sulfur-doped cobalt-nickel bimetallic phosphides(CoNiPS)are specifically designed as a pre-catalyst for navigating a surface reconstruction to fabricate the anions(PO^(3-)_(4) and SO^(2-)_(4))-decorated Co(Ni)OOH catalyst(R-CoNiPS)with exceptional durability and high activity for stable alkaline seawater oxidation(ASO).Various experiment techniques together with theoretical simulations both demonstrate that the in situ-generated PO^(3-)_(4) and SO^(2-)_(4) anions on catalyst surface can improve the oxygen evolution reaction(OER)activity,regulating and stabilizing the catalytic active species Co(Ni)OOH,as well as make a critical role in inhibiting the adsorp-tion of chloride ions and extending the service life of electrode.Therefore,this R-CoNiPS electrode exhi-bits superb OER activity toward AsO and stands out among the non-precious ASO electrocatalysts reported recently,requiring low overpotentials of 420 and 440 mV to attain large current densities of 500 and 1000 mA cm^(-2) in an alkaline natural seawater electrolyte,respectively.Particularly,the catalyst displays a negligible chloride corrosion at room temperature during ASO operation(>200 h)at 500 mA cm^(-2).This work opens up a new viewpoint for designing high-activity and durable electrocata-lystsforseawaterelectrolysis.展开更多
Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions...Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly understood.The batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite oxidation.The one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of pyrite.The Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of aging.Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of pyrite.The significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers.These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.展开更多
Water quality has been found to significantly influence the flotation operations due to the alteration of surface properties of minerals.The effect of cations on the flotation of RE minerals has been studied,however,t...Water quality has been found to significantly influence the flotation operations due to the alteration of surface properties of minerals.The effect of cations on the flotation of RE minerals has been studied,however,there are still very limited information regarding the effect of anions.The present study examined the impact of specific anions such as Cl^(-),SO_(4)^(2-),and HCO_(3)^(-)on the flotation performance of rare earth(RE) ore.This study integrates flotation experiments,rheology measurements,entrainment experiments,zeta potential measurements and settling experiments.It is observed that an increase in the concentration of these anions lead to a decrease in the recovery of RE minerals and an increase in the recovery of FeO minerals and thus negatively affecting flotation efficiency.This adverse effect is most pronounced with Cl^(-)and least noticeable with HCO_(3)^(-).An increase in the non-selective entrainment of gangue minerals is observed when the flotation pulp has higher viscosity.The reduction in the zeta potential of fine particles in the presence of these results in a higher pulp viscosity due to increased attractive forces between particles.These findings were verified by settling experiments and calculations based on the DLVO theory.展开更多
Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number ...Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors.Halogen moieties exhibit strong resistance to oxidative radicals,affecting the dehalogenation and detoxification efficiencies.To address these limitations of AOPs,advanced reduction processes(ARPs)have been proposed.Herein,a novel nucleophilic reductant—namely,the carbon dioxide radical anion(CO_(2)^(·-))—is introduced for the simultaneous degradation,dehalogenation,and detoxification of florfenicol(FF),a typical halogenated antibiotic.The results demonstrate that FF is completely eliminated by CO_(2)^(·-),with approximately 100%of Cland 46%of Freleased after 120 min of treatment.Simultaneous detoxification is observed,which exhibits a linear response to the release of free inorganic halogen ions(R^(2)=0.97,p<0.01).The formation of halogen-free products is the primary reason for the superior detoxification performance of this method,in comparison with conventional hydroxyl-radical-based AOPs.Products identification and density functional theory(DFT)calculations reveal the underlying dehalogenation mechanism,in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by CO_(2)^(·-).Moreover,CO_(2)^(·-)-based ARPs exhibit superior dehalogenation efficiencies(>75%)in degrading a series of halogenated antibiotics,including chloramphenicol(CAP),thiamphenicol(THA),diclofenac(DLF),triclosan(TCS),and ciprofloxacin(CIP).The system shows high tolerance to the pH of the solution and the presence of natural water constituents,and demonstrates an excellent degradation performance in actual groundwater,indicating the strong application potential of CO_(2)^(·-)-based ARPs in real life.Overall,this study elucidates the feasibility of CO_(2)^(·-)for the simultaneous degradation,dehalogenation,and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.展开更多
By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variationa...By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variational Zn-salen ligands RZn and NADH(reduced nicotinamide adenine dinucleotide)mimic modified tridentate ligands with square-planar Pd ions.UV-Vis and luminescence spectra experiments reveal that different anions could selec-tively interact with different sites of Zn-salen modified metal-organic cages to achieve the structural regulation of cage compound,by using the differentiated host-vip electrostatic interactions of counter ions with metal-organic hosts.Compared to other anions,the presence of chloride ions caused the most significant fluorescence emission enhancement of Pd‑R(Zn),meanwhile,the UV-Vis absorption band attributed to the salen aromatic backbone showed an absorption decrease,and the metal-to-ligand induced peak displayed a blue shift effect.Circular dichro-ism and ^(1)H NMR spectra further demonstrate that the introduction of chloride anions is beneficial to keeping a more rigid scaffold.展开更多
Information about electronic excited states of molecular anions plays an important role in investigating electron attachment and detachment processes.Here we present a high-level theoretical study of the electronic st...Information about electronic excited states of molecular anions plays an important role in investigating electron attachment and detachment processes.Here we present a high-level theoretical study of the electronic structures of 12 alkali-metal-containing diatomic anions MX-(MX = LiH,LiF,LiCl,NaF,NaCl,NaBr,RbCl,KCl,KBr,RbI,KI and CsI).The equation-of-motion electron-attachment coupled-cluster singles and doubles(EOM-EA-CCSD) method is used to calculate the electron binding energies(EBEs) of 10 electronic excited states of each of the 12 molecule anions.With addition of different s-/p-/d-type diffusion functions in the basis set,we have identified possible excited dipole bound states(DBSs) of each anion.With the investigation of EBEs on the 12 MXs with dipole moment(DM) up to 12.1 D,we evaluate the dependence of the number of anionic excited DBSs on molecular DM.The results indicate that there are at least two or three DBSs of anions with a molecular DM larger than 7 D and a molecule with DM > 10 D can sustain a π-DBS of the anion.Our study has some implications for the excited DBS electronic states of alkali-metal-containing diatomic molecules.展开更多
Methane is a vital feedstock while the intrinsic inertness of CH_(4)molecule hinders the conversion of methane under mild conditions.Investigating and understanding the mechanism of methane activation is of great impo...Methane is a vital feedstock while the intrinsic inertness of CH_(4)molecule hinders the conversion of methane under mild conditions.Investigating and understanding the mechanism of methane activation is of great importance in chemistry.In this study,tantalum sulfide anions TaS_(3)^(-)were generated by laser ablation method and mass-selected by a quadrupole mass filter to react with methane,ethane,and propane in an ion funnel trap reactor under thermal collision conditions.The reactant and product ions were detected by a time-of-flight mass spectrometer.Experimental results demonstrate that TaS_(3)^(-)is able to adsorb all of the alkane molecules and break the robust C-H bonds.Further density functional theory calculations reveal that TaS_(3)^(-)is a closed-shell species and effectively activates methane via the Ta^(δ+)-S^(δ-)Lewis acid-base pair(LABP,CH_(4)+Ta^(δ+)-S^(δ-)→CH_(3)-Ta-S-H).With a comparative study with NbS_(3)^(-)that contains the Nbδ+-S^(δ-)LABP,the higher reactivity of TaS_(3)^(-)than that of NbS_(3)^(-)can be attributed to the more acidity of Ta^(δ+)than that of Nbδ+.To the best of our knowledge,this study reports the first example of gas phase species TaS_(3)^(-)to activate methane through the metal-sulfur LABP under thermal collision conditions.展开更多
Spectroscopic investigations discovered that the in-situ generated phenylhydrazone anion was significantly bathochromically shifted to visible light region for photoactivation under irradiation. The photoexcited pheny...Spectroscopic investigations discovered that the in-situ generated phenylhydrazone anion was significantly bathochromically shifted to visible light region for photoactivation under irradiation. The photoexcited phenylhydrazone anion was potential to reduce aryl iodides via single electron transfer process for the subsequent radical chain reaction. A redox-neutral photochemical carbonylation of aryl iodides was developed on basis of the special spectroscopic features of phenylhydrazone anion. This protocol provided a convenient and efficient synthetic tool for accessing carbonylation products under redox neutral conditions without the need of transition-metals.展开更多
Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extracti...Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extraction process,resulting in large lattice strains which are the origin of cycledstructure degradations.Here,we demonstrate that the Na-storage lattice strains of layered oxides can be reduced by pushing charge transfer on anions(O^(2-)).Specifically,the designed O3-type Ru-based model compound,which shows an increased charge transfer on anions,displays retarded O3-P3-O1 multiple phase transitions and obviously reduced lattice strains upon cycling as directly revealed by a combination of ex situ X-ray absorption spectroscopy,in situ X-ray diffraction and geometric phase analysis.Meanwhile,the stable Na-storage lattice structure leads to a superior cycling stability with an excellent capacity retention of 84%and ultralow voltage decay of 0.2 mV/cycle after 300 cycles.More broadly,our work highlights an intrinsically structure-regulation strategy to enable a stable cycling structure of layered oxides meanwhile increasing the materials’redox activity and Nadiffusion kinetics.展开更多
Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions...Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions and their dissolution behaviors were investigated based on the combination of single factors-orthogonal experiments and leaching stage experiment. Using a two-stage leaching, 86% of the soluble alkaline anions（CO3^2-, HCO4^-,Al（OH）4^-, OH^-） were leached with a L/S ratio of 2 mL/g, at 30 ℃, over 23 h. During the first stage of leaching, approximately 88% of alkaline anions were leached from the dissolution of free alkali（Na OH, carbonate, bicarbonate, NaAl（OH）4） with the rest originating from the dissolution of alkaline minerals（calcite, cancrinite and hydrogarnet）. Supernatant alkalinity was 69.78 mmol/L with CO3^2- accounting for 75%. Furthermore, carbonate leaching was controlled by solid film diffusion using the Stumm Model with an apparent activation energy of 10.24 kJ/mol.展开更多
A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue leachates.Treatments included,simulated acid rain (AR),pho...A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue leachates.Treatments included,simulated acid rain (AR),phosphogypsum + vermicompost (PVC),phosphogypsum + vermicompost + simulated acid rain (PVA),and biosolids + microorganisms (BSM) together with controls (CK).Results indicated that amendment could effectively reduce the leachate pH and EC values,neutralize OH-,CO32-,HCO3-,and water soluble alkali,and suppress arsenic (As) content.Correlation analysis revealed significant linear correlations with pH and concentrations of OH-,CO32-,HCO3-,water-soluble alkali,and metal ions.BSM treatment showed optimum results with neutralizing anions (OH-,CO32-,and HCO3-),water soluble alkali,and removal of metal ions (Al,As,B,Mo,V,and Na),which was attributed to neutralization from the generation of small molecular organic acids and organic matter during microbial metabolism.BSM treatment reduced alkaline anions and metal ions based on neutralization reactions in bauxite residue leachate,which reduced the potential pollution effects from leachates on the soil surrounding bauxite residue disposal areas.展开更多
Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively st...Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.展开更多
Micro-emulsion usually consists of water, oil, surfactants and co-surfactants, and each component has an effect on the phase behavior and solubilization of the micro-emulsion. When the surfactant in the micro-emulsion...Micro-emulsion usually consists of water, oil, surfactants and co-surfactants, and each component has an effect on the phase behavior and solubilization of the micro-emulsion. When the surfactant in the micro-emulsion system is quaternary ammonium cationic Gemini surfactant, the surfactant mainly combines with the anions in the salt. With the increase of salt concentration, the phase transformation of Winsor I → Winsor III → Winsor II occurred, but the optimum salinity and salt width are different because of the type of salt. The effects of 5 different kinds of monovalent anions, including C_6H_5SO_3^-, I-, Br-, NO_3^- and Cl-, on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are researched by Winsor phase diagram. It is found that the effects of organic anions C_6H_5SO_3-and I-on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are most significant, and the effects of Br-, NO_3^- and Cl-are less significant. Meanwhile, when the optimum solubilization is achieved, the amount of sodium benzoate is the least, indicating that the organic anion has stronger self-organization behavior with quaternary ammonium cationic Gemini surfactants.展开更多
Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions CL^-, SO4^2- and HCO3^- on th...Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions CL^-, SO4^2- and HCO3^- on the release ofCd, Pb, Cu and Zn from the sediments. The results showed that the sequences about the impact of the three anions were Cl^-〉HCO3^-〉SO4^2＋. The release potential of heavy metals in the presence of each anions was in the following order： Cd≥Cu 〉Zn≈Pb. The correlations were positive between CI content and the quantity of Cd released from the marine sediment, whereas there was no significant relationship between CI content and amount of Cu and Zn released. For SO4^2- and HCO3^-, the release of the heavy metals from marine sediments was not obvious.展开更多
Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspa...Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.展开更多
The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmissi...The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and potentiodynamic polarization.The results showed that B_(4)O_(7)^(2−)increased the spark intensity and dissolved most of the oxides at high temperatures.Then,a thicker barrier layer at the coating/substrate interface was produced,which increased the polarization resistance of the coating.PO_(4)^(3−)at a low concentration also promoted the uniform growth of the MAO coating and the formation of hat-shaped holes in the outer deposition layer.The thickness of the MAO coatings obtained in Na_(2)B_(4)O_(7) electrolytes exhibited an exponential increase with time at spark discharge stage,while that of the MAO coating obtained in phosphate–tetraborate electrolytes showed a linear trend as the PO_(4)^(3−)content increased.展开更多
MgH_(2) is regarded as a potential hydrolysis material for the hydrogen generation due to its high theoretical hydrogen yield,abundant source on earth and environmentally friendly hydrolysates.However,the quickly form...MgH_(2) is regarded as a potential hydrolysis material for the hydrogen generation due to its high theoretical hydrogen yield,abundant source on earth and environmentally friendly hydrolysates.However,the quickly formed passive magnesium hydroxide layer on the surface of MgH_(2) will hinder its further hydrolysis reaction,leading to sluggish reaction kinetics and low H_(2) yield.In this paper,we explore the improvement of different anions and cations in solutions for the hydrolysis of MgH_(2).It is found that the cations in the solution promote the reaction rate of MgH_(2) hydrolysis through the hydrolysate-induced growth effect,among which the fastest hydrogen yield can get 1664 m L/g within a few minutes in the Fe_(2)(SO_(4))_(3) solution.As for the anions,it enables different microstructures of the Mg(OH)_(2) hydrolysate which give rise to enhanced water utilization.Specially,for the mixed 0.5 M MgCl_(2)+0.05 M MgSO_(4) solution,the water utilization rate attains the optimum value of 51.3%,much higher than that of the single MgCl_(2) or MgSO_(4) solutions.These findings are of great significance for the application of MgH_(2) hydrolysis as hydrogen generation.展开更多
基金supported by the National Natural Science Foundation of China(22478422,22238012,and 22178384)Science Foundation of China University of Petroleum,Beijing(2462024QNXZ003)CHN Energy Investment Group(GJNY23-23)。
文摘Designing transition metal nickel-cobalt-based battery-type electrode materials driven by anions is crucial for achieving rapid OH-ion transport under electrochemical activation conditions,thereby improving capacitance performance.Herein,borate anions are selected through theoretical calculations,and twodimensional(2D)defect-rich amorphous nickel-cobalt-based borate is synthesized via a facile chemical reduction method.Under potentiostatic modification,activated products(NCB-G-E)are obtained.In situ Raman spectra reveal that electron-deficient borate extracts electrons from metal centers,facilitating the oxidation state transition of Ni and Co.Theoretical calculations show that in situ adsorbed borate regulates the d-band centers of metal sites,enhancing OH^(-)intermediate adsorption.Meanwhile,borate anion adsorption accelerates the deprotonation and activation processes.Electrochemical tests demonstrate that NCB-G-E displays superior capacitance performance,with a high quality specific capacity of383.3 mA h g^(-1)and 65% retention rate at 30 A g^(-1),surpassing most nickel-cobalt-based electrodes.The assembled asymmetric supercapacitor presents an impressive energy density of 68.2 Wh kg^(-1)and good cycling stability.This work highlights the role of electron-deficient borate in tuning metal band structure and promoting oxidation state transition through synergistic defect advantages,offering new prospects for advanced battery-type energy storage materials.
基金supported by the National Natural Science Foundation of China(Nos.52222317,21902144,52225208)the“Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang”(No.2020R01002)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LZ23E020002)the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.RFC2023002).
文摘Anion modification has been considered as a strategy to improve water splitting efficiency upon oxygen evolution reaction(OER).However,constructing a novel catalysis system with high catalytic activity and precise structures is still a huge challenge due to the tedious procedure of precursor synthesis and anion selection.Here,a bimetallic(FeNi)nanowire self-assembled superstructure was synthesized using the Hoffmann rearrangement method,and then functionalized with four anions(P,Se,S,and O).Notably,the Fe_(3)Se_(4)/Ni_(3)Se_(4) catalyst shows a high conductivity,enhances the adsorption of intermediate products,accelerates the rate-determining step,and consequently results to improved electrocatalytic performance.Using the Fe_(3)Se_(4)/Ni_(3)Se_(4) catalyst exhibits enhanced performance with overpotential of 316mV at 10 mA/cm^(2),in stark contrast to Fe_(2) P/Ni_(2)P(357mV),Fe_(7)S_(8)/NiS(379 mV),and Fe_(3)O_(4)/NiO(464 mV).Moreover,the formation mechanism of superstructure and the relationship between electronegativities and electrocatalytic properties,are elucidated.Accordingly,this work provides an efficient approach to Hoffmann-type coordination polymer catalyst for oxygen evolution towards a near future.
基金supports from the National Natural Science Foundation of China(No.22173089,No.21827804,and No.22103075)the National Key R&D Program of China(No.2021YFA0716801 and No.2017YFA0303502).
文摘A plasma injection ion source has been de-veloped for the photoelectron velocity imag-ing studies of metal-containing anions.The source employs a pulse discharge nozzle for generating a plasma beam that perpendicu-larly crosses the master supersonic jet beam from a home-made pulsed piezo valve.The discharge nozzle is designed for high voltage gas discharge with efficient metal sputtering of the cathode,and thus plays a role in met-al atom and ion source.Supersonically jet-cooled anions can be produced in the master gas jet via reactions of the plasma products.The source is integrated into a photoelectron ve-locity imaging spectrometer.Test mass spectrometry experiments show that the ion source can efficiently produce transition metal containing anions,such as FeO_(m)^(-),CuO_(m)^(-),CuC_(n)^(-),CuC_(n)O_(m)^(-).The photoelectron imaging results by photodetachment of O-show that the pho-toelectron energy resolution of the whole instrument isΔE/E≈2.3%,and the results of FeO^(-)indicate that internal temperatures of anions from the source could be efficiently cooled down.
基金the funding support from the National Natural Science Foundation of China (U22A2078)the Fundamental Research Funds of Central Universities (2022CDJQY-007 and 2022CDJJCLK001)
文摘The development of efficient and robust anode materials for stable alkaline seawater electrolysis is severely limited by chlorine evolution reaction and chloride corrosion.Here,the sulfur-doped cobalt-nickel bimetallic phosphides(CoNiPS)are specifically designed as a pre-catalyst for navigating a surface reconstruction to fabricate the anions(PO^(3-)_(4) and SO^(2-)_(4))-decorated Co(Ni)OOH catalyst(R-CoNiPS)with exceptional durability and high activity for stable alkaline seawater oxidation(ASO).Various experiment techniques together with theoretical simulations both demonstrate that the in situ-generated PO^(3-)_(4) and SO^(2-)_(4) anions on catalyst surface can improve the oxygen evolution reaction(OER)activity,regulating and stabilizing the catalytic active species Co(Ni)OOH,as well as make a critical role in inhibiting the adsorp-tion of chloride ions and extending the service life of electrode.Therefore,this R-CoNiPS electrode exhi-bits superb OER activity toward AsO and stands out among the non-precious ASO electrocatalysts reported recently,requiring low overpotentials of 420 and 440 mV to attain large current densities of 500 and 1000 mA cm^(-2) in an alkaline natural seawater electrolyte,respectively.Particularly,the catalyst displays a negligible chloride corrosion at room temperature during ASO operation(>200 h)at 500 mA cm^(-2).This work opens up a new viewpoint for designing high-activity and durable electrocata-lystsforseawaterelectrolysis.
基金supported by the National Natural Science Foundation of China (No.51709157)the Youth Interdisciplinary Science and Innovative Research Groups of Shandong University (No.2020QNQT014)。
文摘Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly understood.The batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite oxidation.The one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of pyrite.The Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of aging.Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of pyrite.The significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers.These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.
基金The financial assistance of the Minerals Research Institute of Western AustraliaLynas Rare Earth LtdCurtin University (Grant number:M0537)。
文摘Water quality has been found to significantly influence the flotation operations due to the alteration of surface properties of minerals.The effect of cations on the flotation of RE minerals has been studied,however,there are still very limited information regarding the effect of anions.The present study examined the impact of specific anions such as Cl^(-),SO_(4)^(2-),and HCO_(3)^(-)on the flotation performance of rare earth(RE) ore.This study integrates flotation experiments,rheology measurements,entrainment experiments,zeta potential measurements and settling experiments.It is observed that an increase in the concentration of these anions lead to a decrease in the recovery of RE minerals and an increase in the recovery of FeO minerals and thus negatively affecting flotation efficiency.This adverse effect is most pronounced with Cl^(-)and least noticeable with HCO_(3)^(-).An increase in the non-selective entrainment of gangue minerals is observed when the flotation pulp has higher viscosity.The reduction in the zeta potential of fine particles in the presence of these results in a higher pulp viscosity due to increased attractive forces between particles.These findings were verified by settling experiments and calculations based on the DLVO theory.
基金financially supported by the National Natural Science Foundation of China(22176059,21777042,and 22076045)the authors would also like to acknowledge support from the Science and Technology Commission of Shanghai Municipality’s Yangfan Special Project(23YF1408400)the Fundamental Research Funds for the Central Universities.
文摘Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors.Halogen moieties exhibit strong resistance to oxidative radicals,affecting the dehalogenation and detoxification efficiencies.To address these limitations of AOPs,advanced reduction processes(ARPs)have been proposed.Herein,a novel nucleophilic reductant—namely,the carbon dioxide radical anion(CO_(2)^(·-))—is introduced for the simultaneous degradation,dehalogenation,and detoxification of florfenicol(FF),a typical halogenated antibiotic.The results demonstrate that FF is completely eliminated by CO_(2)^(·-),with approximately 100%of Cland 46%of Freleased after 120 min of treatment.Simultaneous detoxification is observed,which exhibits a linear response to the release of free inorganic halogen ions(R^(2)=0.97,p<0.01).The formation of halogen-free products is the primary reason for the superior detoxification performance of this method,in comparison with conventional hydroxyl-radical-based AOPs.Products identification and density functional theory(DFT)calculations reveal the underlying dehalogenation mechanism,in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by CO_(2)^(·-).Moreover,CO_(2)^(·-)-based ARPs exhibit superior dehalogenation efficiencies(>75%)in degrading a series of halogenated antibiotics,including chloramphenicol(CAP),thiamphenicol(THA),diclofenac(DLF),triclosan(TCS),and ciprofloxacin(CIP).The system shows high tolerance to the pH of the solution and the presence of natural water constituents,and demonstrates an excellent degradation performance in actual groundwater,indicating the strong application potential of CO_(2)^(·-)-based ARPs in real life.Overall,this study elucidates the feasibility of CO_(2)^(·-)for the simultaneous degradation,dehalogenation,and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.
文摘By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variational Zn-salen ligands RZn and NADH(reduced nicotinamide adenine dinucleotide)mimic modified tridentate ligands with square-planar Pd ions.UV-Vis and luminescence spectra experiments reveal that different anions could selec-tively interact with different sites of Zn-salen modified metal-organic cages to achieve the structural regulation of cage compound,by using the differentiated host-vip electrostatic interactions of counter ions with metal-organic hosts.Compared to other anions,the presence of chloride ions caused the most significant fluorescence emission enhancement of Pd‑R(Zn),meanwhile,the UV-Vis absorption band attributed to the salen aromatic backbone showed an absorption decrease,and the metal-to-ligand induced peak displayed a blue shift effect.Circular dichro-ism and ^(1)H NMR spectra further demonstrate that the introduction of chloride anions is beneficial to keeping a more rigid scaffold.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12274178 and 12174148)Support of High Performance Computing Center of Jilin Universitythe high-performance computing cluster Tiger@IAMP。
文摘Information about electronic excited states of molecular anions plays an important role in investigating electron attachment and detachment processes.Here we present a high-level theoretical study of the electronic structures of 12 alkali-metal-containing diatomic anions MX-(MX = LiH,LiF,LiCl,NaF,NaCl,NaBr,RbCl,KCl,KBr,RbI,KI and CsI).The equation-of-motion electron-attachment coupled-cluster singles and doubles(EOM-EA-CCSD) method is used to calculate the electron binding energies(EBEs) of 10 electronic excited states of each of the 12 molecule anions.With addition of different s-/p-/d-type diffusion functions in the basis set,we have identified possible excited dipole bound states(DBSs) of each anion.With the investigation of EBEs on the 12 MXs with dipole moment(DM) up to 12.1 D,we evaluate the dependence of the number of anionic excited DBSs on molecular DM.The results indicate that there are at least two or three DBSs of anions with a molecular DM larger than 7 D and a molecule with DM > 10 D can sustain a π-DBS of the anion.Our study has some implications for the excited DBS electronic states of alkali-metal-containing diatomic molecules.
基金supported by the National Natural Science Foundation of China(No.92161205 and No.22121002)the Youth Innovation Promotion Association of CAS(No.2022033).
文摘Methane is a vital feedstock while the intrinsic inertness of CH_(4)molecule hinders the conversion of methane under mild conditions.Investigating and understanding the mechanism of methane activation is of great importance in chemistry.In this study,tantalum sulfide anions TaS_(3)^(-)were generated by laser ablation method and mass-selected by a quadrupole mass filter to react with methane,ethane,and propane in an ion funnel trap reactor under thermal collision conditions.The reactant and product ions were detected by a time-of-flight mass spectrometer.Experimental results demonstrate that TaS_(3)^(-)is able to adsorb all of the alkane molecules and break the robust C-H bonds.Further density functional theory calculations reveal that TaS_(3)^(-)is a closed-shell species and effectively activates methane via the Ta^(δ+)-S^(δ-)Lewis acid-base pair(LABP,CH_(4)+Ta^(δ+)-S^(δ-)→CH_(3)-Ta-S-H).With a comparative study with NbS_(3)^(-)that contains the Nbδ+-S^(δ-)LABP,the higher reactivity of TaS_(3)^(-)than that of NbS_(3)^(-)can be attributed to the more acidity of Ta^(δ+)than that of Nbδ+.To the best of our knowledge,this study reports the first example of gas phase species TaS_(3)^(-)to activate methane through the metal-sulfur LABP under thermal collision conditions.
基金supported by the National Natural Science Foundation of China (Nos.22271246 and 22101251)Yunling Scholar Project of "Yunnan Revitalization Talent Support Program" for financial support。
文摘Spectroscopic investigations discovered that the in-situ generated phenylhydrazone anion was significantly bathochromically shifted to visible light region for photoactivation under irradiation. The photoexcited phenylhydrazone anion was potential to reduce aryl iodides via single electron transfer process for the subsequent radical chain reaction. A redox-neutral photochemical carbonylation of aryl iodides was developed on basis of the special spectroscopic features of phenylhydrazone anion. This protocol provided a convenient and efficient synthetic tool for accessing carbonylation products under redox neutral conditions without the need of transition-metals.
基金supported by the National Natural Science Foundation of China(Grant No.12105197 and 52088101)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010319)+1 种基金the open research fund of Songshan Lake Materials Laboratory(No.2022SLABFK04)Large Scientific Facility Open Subject of Songshan Lake,Dongguan,Guangdong
文摘Due to a high energy density,layered transition-metal oxides have gained much attention as the promising sodium-ion batteries cathodes.However,they readily suffer from multiple phase transitions during the Na extraction process,resulting in large lattice strains which are the origin of cycledstructure degradations.Here,we demonstrate that the Na-storage lattice strains of layered oxides can be reduced by pushing charge transfer on anions(O^(2-)).Specifically,the designed O3-type Ru-based model compound,which shows an increased charge transfer on anions,displays retarded O3-P3-O1 multiple phase transitions and obviously reduced lattice strains upon cycling as directly revealed by a combination of ex situ X-ray absorption spectroscopy,in situ X-ray diffraction and geometric phase analysis.Meanwhile,the stable Na-storage lattice structure leads to a superior cycling stability with an excellent capacity retention of 84%and ultralow voltage decay of 0.2 mV/cycle after 300 cycles.More broadly,our work highlights an intrinsically structure-regulation strategy to enable a stable cycling structure of layered oxides meanwhile increasing the materials’redox activity and Nadiffusion kinetics.
基金Project(41371475)supported by the National Natural Science Foundation of ChinaProject(201509048)supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare Industry
文摘Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions and their dissolution behaviors were investigated based on the combination of single factors-orthogonal experiments and leaching stage experiment. Using a two-stage leaching, 86% of the soluble alkaline anions（CO3^2-, HCO4^-,Al（OH）4^-, OH^-） were leached with a L/S ratio of 2 mL/g, at 30 ℃, over 23 h. During the first stage of leaching, approximately 88% of alkaline anions were leached from the dissolution of free alkali（Na OH, carbonate, bicarbonate, NaAl（OH）4） with the rest originating from the dissolution of alkaline minerals（calcite, cancrinite and hydrogarnet）. Supernatant alkalinity was 69.78 mmol/L with CO3^2- accounting for 75%. Furthermore, carbonate leaching was controlled by solid film diffusion using the Stumm Model with an apparent activation energy of 10.24 kJ/mol.
基金supported by the National Natural Science Foundation of China(Nos.41701587,41877511)the Open Sharing Fund for the Large-scale Instruments,Euipments of Central South University(No.CSUZC201904)the Fundamental Research Funds for the Central Universities of Central South University
文摘A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue leachates.Treatments included,simulated acid rain (AR),phosphogypsum + vermicompost (PVC),phosphogypsum + vermicompost + simulated acid rain (PVA),and biosolids + microorganisms (BSM) together with controls (CK).Results indicated that amendment could effectively reduce the leachate pH and EC values,neutralize OH-,CO32-,HCO3-,and water soluble alkali,and suppress arsenic (As) content.Correlation analysis revealed significant linear correlations with pH and concentrations of OH-,CO32-,HCO3-,water-soluble alkali,and metal ions.BSM treatment showed optimum results with neutralizing anions (OH-,CO32-,and HCO3-),water soluble alkali,and removal of metal ions (Al,As,B,Mo,V,and Na),which was attributed to neutralization from the generation of small molecular organic acids and organic matter during microbial metabolism.BSM treatment reduced alkaline anions and metal ions based on neutralization reactions in bauxite residue leachate,which reduced the potential pollution effects from leachates on the soil surrounding bauxite residue disposal areas.
基金financially supported by the National Natural Science Foundation of China(No.U1301212)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB15030202)
文摘Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.
基金Supported by China Petroleum Science and Technology Innovation Fund(2017D-5007-0601)State Key Laboratory of Heavy Oil Processing and China University of Petroleum(East China)2018 Graduate Engineering Innovation Project Found(SLKZZ-2017002)
文摘Micro-emulsion usually consists of water, oil, surfactants and co-surfactants, and each component has an effect on the phase behavior and solubilization of the micro-emulsion. When the surfactant in the micro-emulsion system is quaternary ammonium cationic Gemini surfactant, the surfactant mainly combines with the anions in the salt. With the increase of salt concentration, the phase transformation of Winsor I → Winsor III → Winsor II occurred, but the optimum salinity and salt width are different because of the type of salt. The effects of 5 different kinds of monovalent anions, including C_6H_5SO_3^-, I-, Br-, NO_3^- and Cl-, on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are researched by Winsor phase diagram. It is found that the effects of organic anions C_6H_5SO_3-and I-on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are most significant, and the effects of Br-, NO_3^- and Cl-are less significant. Meanwhile, when the optimum solubilization is achieved, the amount of sodium benzoate is the least, indicating that the organic anion has stronger self-organization behavior with quaternary ammonium cationic Gemini surfactants.
基金The National Basic Research Program (973) of China (No. 2004CB3418501)
文摘Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions CL^-, SO4^2- and HCO3^- on the release ofCd, Pb, Cu and Zn from the sediments. The results showed that the sequences about the impact of the three anions were Cl^-〉HCO3^-〉SO4^2＋. The release potential of heavy metals in the presence of each anions was in the following order： Cd≥Cu 〉Zn≈Pb. The correlations were positive between CI content and the quantity of Cd released from the marine sediment, whereas there was no significant relationship between CI content and amount of Cu and Zn released. For SO4^2- and HCO3^-, the release of the heavy metals from marine sediments was not obvious.
基金supported by the Natural Science Foundation of Chongqing(cstc2019jcyjmsxm X0566,cstc2018jcyj AX0450,cstc2018jcyj A2923,cstc2017jcyj AX0393)Projects of President Foundation of Chongqing University(2019CDXZWL002)+3 种基金Fundamental Research Funds for the Central Universities(2019CDXYWL0029,2018CDJDWL0011,106112017CDJQJ328839,106112016CDJZR288805)Science and Technology Research Program of Chongqing Municipal Education Commission(KJKJQN201800102,KJQN201800619,KJ1703042)NSFC(11544010,11374359,11304405 and 1155305)the Sharing Fund of Large-scale Equipment of Chongqing University(201903150094)
文摘Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.
文摘The growth kinetics of microarc oxidation(MAO)coatings on Ti6Al4V alloy was studied by designing an electrolyte with low PO_(4)^(3−)content and high B_(4)O_(7)^(2−)content,using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and potentiodynamic polarization.The results showed that B_(4)O_(7)^(2−)increased the spark intensity and dissolved most of the oxides at high temperatures.Then,a thicker barrier layer at the coating/substrate interface was produced,which increased the polarization resistance of the coating.PO_(4)^(3−)at a low concentration also promoted the uniform growth of the MAO coating and the formation of hat-shaped holes in the outer deposition layer.The thickness of the MAO coatings obtained in Na_(2)B_(4)O_(7) electrolytes exhibited an exponential increase with time at spark discharge stage,while that of the MAO coating obtained in phosphate–tetraborate electrolytes showed a linear trend as the PO_(4)^(3−)content increased.
基金supported by the National Key Research and Development Program of China(2017YFA0204600)the National Science Fund for Distinguished Young Scholars(51625102)+2 种基金the National Natural Science Foundation of China(51971065)the Innovation Program of Shanghai Municipal Education Commission(2019–01–07–00–07-E00028)the financial support from ARC(DP170101773)。
文摘MgH_(2) is regarded as a potential hydrolysis material for the hydrogen generation due to its high theoretical hydrogen yield,abundant source on earth and environmentally friendly hydrolysates.However,the quickly formed passive magnesium hydroxide layer on the surface of MgH_(2) will hinder its further hydrolysis reaction,leading to sluggish reaction kinetics and low H_(2) yield.In this paper,we explore the improvement of different anions and cations in solutions for the hydrolysis of MgH_(2).It is found that the cations in the solution promote the reaction rate of MgH_(2) hydrolysis through the hydrolysate-induced growth effect,among which the fastest hydrogen yield can get 1664 m L/g within a few minutes in the Fe_(2)(SO_(4))_(3) solution.As for the anions,it enables different microstructures of the Mg(OH)_(2) hydrolysate which give rise to enhanced water utilization.Specially,for the mixed 0.5 M MgCl_(2)+0.05 M MgSO_(4) solution,the water utilization rate attains the optimum value of 51.3%,much higher than that of the single MgCl_(2) or MgSO_(4) solutions.These findings are of great significance for the application of MgH_(2) hydrolysis as hydrogen generation.
