With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has ...With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has the advantages of low water consumption and low hazardous waste during REE recovery.This review systematically summarizes the separation and electroextraction of REEs on various reactive electrodes in different molten salts.It also highlights the relationship between the formed alloy phases and electrodeposition parameters,including applied potential,current,and ion concentration.Moreover,the feasibility of using LiF–NaF–KF electrolyte to recover REEs is evaluated through thermodynamic analysis.Problems related to REE separation/recovery the choice of electrolyte are discussed in detail to realize the low-energy and high current efficiency of practical applications.展开更多
Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based products.However,this capability provides an obstacle to increasing the selectivity for a single prod...Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based products.However,this capability provides an obstacle to increasing the selectivity for a single product.Herein,we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly(MEA)-based CO_(2) electrolyzer for the electrochemical CO_(2) reduction reaction(ECRR)with high selectivity for CO production.When the composition of the Cu-Pd alloy catalyst was fabricated at 6:4,the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is suppressed.Introducing a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEAbased CO_(2) electrolyzer showed a CO faradaic efficiency of 92.8%at 2.4 V_(cell).We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd alloy.The phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C_(2)H_4 at high voltage.The results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy,the desorption of~*CO is suppressed,suggesting that C-C coupling reaction is favored.展开更多
Alloy nanostructures have been extensively exploited in both thermal and electrochemical catalysis due to their beneficial“synergetic effects”and being cost-effective.Understandings of the alloy nanostructures inclu...Alloy nanostructures have been extensively exploited in both thermal and electrochemical catalysis due to their beneficial“synergetic effects”and being cost-effective.Understandings of the alloy nanostructures including phases,interfaces,and chemical composition are prerequisites for utilizing them as efficient electrocatalysts.Here,we use carbon-supported CuAu nanoparticles as a model catalyst to demonstrate the phase-separation induced variation of electrochemical performance for the CO_(2)reduction reaction.Driven by thermal oxidation,the CuOx phase gradually separates from the original CuAu nanoparticles,and different carbon supports,i.e.,graphene vs.carbon nanotube lead to a reversed trend in the selectivity towards CO production.Through detailed structural and chemical analysis,we find the extent of phase separation holds the key to this variation and could be used as an effective method to tune the electrochemical properties of the alloy phase.展开更多
The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was ...The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.展开更多
Heavy metal pollution is a key environmental problem.Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously.Adsorption is a promising approach with a facile proce...Heavy metal pollution is a key environmental problem.Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously.Adsorption is a promising approach with a facile process,adaptability for the broad concentration of feed water,and high selectivity.However,the adsorption method faces challenges in synthesizing highperformance sorbents and regenerating adsorbents effectively.FeOOH is an environmentally friendly sorbent with low-cost production on a large scale.Nevertheless,the selectivity behavior and regeneration of FeOOH are seldom studied.Therefore,we investigated the selectivity of FeOOH in a mixed solution of Co^(2+),Ni^(2+),and Pb^(2+)and proposed to enhance the capacity of FeOOH and regenerate it by using external charges.Without charge,the FeOOH electrode shows a Pb^(2+)uptake capacity of 20 mg/g.After applying a voltage of-0.2/+0.8 V,the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%-80%.In 35 cycles,FeOOH shows a superior selectivity towards Pb^(2+)compared with Co^(2+)and Ni^(2+),with a purity of 97%±3%in the extracts.The high selectivity is attributed to the lower activation energy for Pb^(2+)sorption.The capacity retentions at the 5^(th)and the 35^(th)cycles are ca.80%and ca.50%,respectively,comparable to the chemical regeneration method.With industrially exhausted granular ferric hydroxide as the electrode material,the system exhibits a Pb^(2+)uptake capacity of 37.4 mg/g with high selectivity.Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent.展开更多
Enantiomeric separation of epinephrine and salbutamol was investigated by micellar electrokinetic chromatography employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution. The analytes were de...Enantiomeric separation of epinephrine and salbutamol was investigated by micellar electrokinetic chromatography employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution. The analytes were detected by electrochemistry using gold microelectrode at +0.65 V versus SCE reference electrode. The effects of detection potential, concentration of β-cyclodextrin, concentration of sodium dodecyl sulfate, pH value of electrolyte and applied voltage were discussed.展开更多
This paper presents a novel method to fabricate separated macroporous silicon using a single step of photo-assisted electrochemical etching. The method is applied to fabricate silicon microchannel plates in 1 O0 mm p-...This paper presents a novel method to fabricate separated macroporous silicon using a single step of photo-assisted electrochemical etching. The method is applied to fabricate silicon microchannel plates in 1 O0 mm p-type silicon wafers, which can be used as electron multipliers and three-dimensional Li-ion microbatteries. Increasing the backside illumination intensity and decreasing the bias simultaneously can generate additional holes during the electrochemical etching which will create lateral etching at the pore tips. In this way the silicon microchannel can be separated from the substrate when the desired depth is reached, then it can be cut into the desired shape by using a laser cutting machine. Also, the mechanism of lateral etching is proposed.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.21976047,21790373,and 51774104)the Ph.D Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(No.3072019GIP1011)+1 种基金University and Local Integration Development Project of Yantai,China(No.2020 XDRHXMPT36)the Sino-Russian Cooperation Fund of Harbin Engineering University(No.2021HEUCRF004).
文摘With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has the advantages of low water consumption and low hazardous waste during REE recovery.This review systematically summarizes the separation and electroextraction of REEs on various reactive electrodes in different molten salts.It also highlights the relationship between the formed alloy phases and electrodeposition parameters,including applied potential,current,and ion concentration.Moreover,the feasibility of using LiF–NaF–KF electrolyte to recover REEs is evaluated through thermodynamic analysis.Problems related to REE separation/recovery the choice of electrolyte are discussed in detail to realize the low-energy and high current efficiency of practical applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government MSIT(2021R1A2C2093358,2021R1A4A3027878,2022M3I3A1081901)financial support from the Lotte Chemical Company。
文摘Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based products.However,this capability provides an obstacle to increasing the selectivity for a single product.Herein,we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly(MEA)-based CO_(2) electrolyzer for the electrochemical CO_(2) reduction reaction(ECRR)with high selectivity for CO production.When the composition of the Cu-Pd alloy catalyst was fabricated at 6:4,the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is suppressed.Introducing a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEAbased CO_(2) electrolyzer showed a CO faradaic efficiency of 92.8%at 2.4 V_(cell).We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd alloy.The phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C_(2)H_4 at high voltage.The results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy,the desorption of~*CO is suppressed,suggesting that C-C coupling reaction is favored.
基金support from the National Natural Science Foundation of China(No.22172110)。
文摘Alloy nanostructures have been extensively exploited in both thermal and electrochemical catalysis due to their beneficial“synergetic effects”and being cost-effective.Understandings of the alloy nanostructures including phases,interfaces,and chemical composition are prerequisites for utilizing them as efficient electrocatalysts.Here,we use carbon-supported CuAu nanoparticles as a model catalyst to demonstrate the phase-separation induced variation of electrochemical performance for the CO_(2)reduction reaction.Driven by thermal oxidation,the CuOx phase gradually separates from the original CuAu nanoparticles,and different carbon supports,i.e.,graphene vs.carbon nanotube lead to a reversed trend in the selectivity towards CO production.Through detailed structural and chemical analysis,we find the extent of phase separation holds the key to this variation and could be used as an effective method to tune the electrochemical properties of the alloy phase.
基金Project supported by Ministry of Industry and Trade of the Czech Republic
文摘The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.
基金L.W.acknowledges funding from the Chinese Scholarship Council(CSC,No.201906260277)The work of L.D.was part of theÉcole Européenne d’Ingénieurs en Génie des Matériaux(EEIGM)carried out at Saarland University.Work at the Molecular Foundry was supported by the Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy(No.DE-AC02-05CH11231)We acknowledge support for the eLiRec project by the European Union from the European Regional Development Fund(EFRE)and the State of Saarland,Germany.S.J.Z.acknowledges support from Tulane University.
文摘Heavy metal pollution is a key environmental problem.Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously.Adsorption is a promising approach with a facile process,adaptability for the broad concentration of feed water,and high selectivity.However,the adsorption method faces challenges in synthesizing highperformance sorbents and regenerating adsorbents effectively.FeOOH is an environmentally friendly sorbent with low-cost production on a large scale.Nevertheless,the selectivity behavior and regeneration of FeOOH are seldom studied.Therefore,we investigated the selectivity of FeOOH in a mixed solution of Co^(2+),Ni^(2+),and Pb^(2+)and proposed to enhance the capacity of FeOOH and regenerate it by using external charges.Without charge,the FeOOH electrode shows a Pb^(2+)uptake capacity of 20 mg/g.After applying a voltage of-0.2/+0.8 V,the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%-80%.In 35 cycles,FeOOH shows a superior selectivity towards Pb^(2+)compared with Co^(2+)and Ni^(2+),with a purity of 97%±3%in the extracts.The high selectivity is attributed to the lower activation energy for Pb^(2+)sorption.The capacity retentions at the 5^(th)and the 35^(th)cycles are ca.80%and ca.50%,respectively,comparable to the chemical regeneration method.With industrially exhausted granular ferric hydroxide as the electrode material,the system exhibits a Pb^(2+)uptake capacity of 37.4 mg/g with high selectivity.Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent.
文摘Enantiomeric separation of epinephrine and salbutamol was investigated by micellar electrokinetic chromatography employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution. The analytes were detected by electrochemistry using gold microelectrode at +0.65 V versus SCE reference electrode. The effects of detection potential, concentration of β-cyclodextrin, concentration of sodium dodecyl sulfate, pH value of electrolyte and applied voltage were discussed.
基金Project supported by the International Collaboration Project of China(No.10520704400)PCSIRT,the National Natural Science Foundation of China(No.61176108)the City University of Hong Kong Strategic Research Grant,China(No.7008009)
文摘This paper presents a novel method to fabricate separated macroporous silicon using a single step of photo-assisted electrochemical etching. The method is applied to fabricate silicon microchannel plates in 1 O0 mm p-type silicon wafers, which can be used as electron multipliers and three-dimensional Li-ion microbatteries. Increasing the backside illumination intensity and decreasing the bias simultaneously can generate additional holes during the electrochemical etching which will create lateral etching at the pore tips. In this way the silicon microchannel can be separated from the substrate when the desired depth is reached, then it can be cut into the desired shape by using a laser cutting machine. Also, the mechanism of lateral etching is proposed.
