Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains...Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.展开更多
The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with...The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with a hard combination,a numerical model is developed in this study.The indoor model test verified the accuracy of the numerical model.The influence laws of different hard combinations,train operating speeds and modes were studied and evaluated accordingly.The results show that the frequency corresponding to the peak vibration acceleration level of each floor of the superstructure property is concentrated at 10–20 Hz.The vibration response decreases in the high-frequency parts and increases in the lowfrequency parts with increasing distance from the source.Furthermore,the factors,such as train operating speed,operating mode,and hard combination type,will affect the vibration of the superstructure.The vibration response under the reversible operation of the train is greater than that of the unidirectional operation.The operating speed of the train is proportional to its vibration response.The vibration amplification area appears between the middle and the top of the superstructure at a higher train speed.Its vibration acceleration level will exceed the limit value of relevant regulations,and vibration-damping measures are required.Within the scope of application,this study provides some suggestions for constructing subway stations and superstructures.展开更多
Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the...Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the requirements for applications in emerging fields such as renewable energy and electric vehicles due to limitations including a disordered structure and uncontrolled defects.With an aim of realizing devisable structures,adjustable functions,and performance breakthroughs,superstructured carbons is proposed and represent a category of carbon-based materials,characterized by precisely-built pores,networks,and interfaces.Superstructured carbons can overcome the limitations of traditional carbon materials and improve the performance of energy storage and conversion devices.We review the structure-activity relationships of superstructured carbons and recent research advances from three aspects including a precisely customized pore structure,a dense carbon network framework,and a multi-component highly coupled interface between the different components.Finally,we provide an outlook on the future development of and practical challenges in energy storage and conversion devices.展开更多
The novel fabrication of multiple components and unique heterostructure can inject infinite vitality into the electromagnetic wave(EMW)attenuation field.Herein,through the self-assembly of polyimide com-plexes and cat...The novel fabrication of multiple components and unique heterostructure can inject infinite vitality into the electromagnetic wave(EMW)attenuation field.Herein,through the self-assembly of polyimide com-plexes and catalytic chemical vapor deposition,porous carbon microflowers were synthesized accompa-nied by carbon nanotubes(CNTs).By regulating the metal ions,the composition and structure of the as-obtained hybrids are modified correspondingly,and thus the adjustable thermal management and EMW absorption capabilities are obtained.In detail,the rich pores and huge specific surface area endow the hierarchical structures with distinguished thermal insulation ability(λ<0.07).The carbon framework and CNTs are beneficial for consuming EMWs via conductive loss and defect polarization loss while reduc-ing the filling ratio and thickness.The doped heteroatoms and abundant heterointerfaces generate ample dipole polarization and interface polarization losses(supported by DFT calculation).The metal nanopar-ticles uniformly embedded in the carbon framework offer optimized impedance matching,proper de-fect polarization,and suitable magnetic loss.Accordingly,the synergy of magnetic-dielectric balance and flower-like superstructure enables FNCFN2 and NNCFN2 to accomplish remarkable microwave absorbing capacity with thin thickness(14 wt.%).Therefore,respectable specific reflection loss and specific effec-tive absorption bandwidth are acquired(215.39 dB mm^(-1) and 22.10 GHz mm^(-1),257.23 dB mm^(-1) and 22.12 GHz mm^(-1) respectively),superior to those of certain renowned carbon-based absorbers.The simu-lation results of electric field intensity distributions,power loss density,and radar cross section reduction(maximum value of 36.02 dBm2)also verify the prominent radar stealth capability.Moreover,the cus-tomizable approach can be applied to other metals to obtain fulfilling behaviors.Henceforth,this work provides profound insights into the relationship between structure and performance,and proposes an efficient path for mass-producing multifunctional and high-performance EMW absorbers with excellent thermal properties.展开更多
Improving the surface atoms utilization efficiency of catalysts is extremely important for large-scale H_(2)production by electrochemical water splitting,but it remains a great challenge.Herein,we reported two kinds o...Improving the surface atoms utilization efficiency of catalysts is extremely important for large-scale H_(2)production by electrochemical water splitting,but it remains a great challenge.Herein,we reported two kinds of Mo O_(3)-polyoxometalate hybrid nanobelt superstructures(MoO_(3)-POM HNSs,POM=PW_(12)O_(40)and Si W_(12)O_(40))using a simple hydrothermal method.Such superstructure with highly uniform nanoparticles as building blocks can expose more surface atoms and emanate increased specific surface area.The incorporated POMs generated abundant oxygen vacancies,improved the electronic mobility,and modulated the surface electronic structure of MoO_(3),allowing to optimize the H^(*)adsorption/desorption and dehydrogenation kinetics of catalyst.Notably,the as-prepared MoO_(3)-PW_(12)O_(40)HNSs electrodes not only displayed the low overpotentials of 108 mV at 10 mA/cm^(2)current density in 0.5 mol/L H_(2)SO_(4)electrolyte but also displayed excellent long-term stability.The hydrogen evolution reaction(HER)performance of MoO_(3)-POM superstructures is significantly better than that of corresponding bulk materials MoO_(3)@PW_(12)O_(40)and Mo O_(3)@Si W_(12)O_(40),and the overpotentials are about 8.3 and 4.9 times lower than that of single Mo O_(3).This work opens an avenue for designing highly surface-exposed catalysts for electrocatalytic H_(2)production and other electrochemical applications.展开更多
The rise of Zn-ion hybrid capacitor(ZHC)has imposed high requirements on carbon cathodes,including reasonable configuration,high specific surface area,multiscale pores,and abundant defects.To achieve this objective,a ...The rise of Zn-ion hybrid capacitor(ZHC)has imposed high requirements on carbon cathodes,including reasonable configuration,high specific surface area,multiscale pores,and abundant defects.To achieve this objective,a template-oriented strategy coupled with multi-heteroatom modification is proposed to precisely synthesize a three-dimensional boron/nitrogen-rich carbon nanoflake-interconnected micro/nano superstructure,referred to as BNPC.The hierarchically porous framework of BNPC shares short channels for fast Zn2+transport,increased adsorption-site accessibility,and structural robustness.Additionally,the boron/nitrogen incorporation effect significantly augments Zn2+adsorption capability and more distinctive pseudocapacitive nature,notably enhancing Zn-ion storage and transmission kinetics by performing the dual-storage mechanism of the electric double-layer capacitance and Faradaic redox process in BNPC cathode.These merits contribute to a high capacity(143.7 mAh g^(-1)at 0.2 A g^(-1))and excellent rate capability(84.5 mAh g^(-1)at 30 A g^(-1))of BNPC-based aqueous ZHC,and the ZHC still shows an ultrahigh capacity of 108.5 mAh g^(-1)even under a high BNPC mass loading of 12 mg cm^(-2).More critically,the BNPC-based flexible device also sustains notable cyclability over 30,000 cycles and low-rate self-discharge of 2.13 mV h-1 along with a preeminent energy output of 117.15 Wh kg^(-1)at a power density of 163.15Wkg^(-1),favoring a creditable applicability in modern electronics.In/ex-situ analysis and theoretical calculations elaborately elucidate the enhanced charge storage mechanism in depth.The findings offer a promising platform for the development of advanced carbon cathodes and corresponding electrochemical devices.展开更多
Designing carbon materials with ideal stable hierarchical porous structures and fiexible functional properties for efficient and sustainable Zn2+ion storage still faces great challenges. Herein, the threedimensional c...Designing carbon materials with ideal stable hierarchical porous structures and fiexible functional properties for efficient and sustainable Zn2+ion storage still faces great challenges. Herein, the threedimensional carbon superstructures with spherical nanofiower-like structures were tailor-made by the self-assembly strategy. Specifically, organic polymer units(i.e., organic motifs) were formed by tetrachloro-p-benzoquinone(TBQ) and 2,6-diamino anthraquinone(DAQ) via a noble-metal-free catalyzed coupling reaction. Subsequently, the organic motifs assemble into spherical nanofiower-like superstructures induced by intermolecular hydrogen bonding and aromatic π-π stacking interactions. Welldesigned carbon superstructures can provide a stable backbone that effectively blocks structural stacking and collapse. Meanwhile, the hierarchical porous structures in 3D carbon superstructures provide continuous charge transport pathways to greatly shorten the ion diffusion distance, and as a result, the carbon superstructures-based zinc-ion hybrid capacitors(ZIHCs) provide a capacity of 245 m Ah/g at 0.5 A/g, a high energy density of 152 Wh/kg and an ultra-long life of 300,000 cycles at 20 A/g. The excellent electrochemical performance is also attributed to the corresponding charge storage mechanism, i.e., the alternate binding of Zn^(2+)/CF_(3)SO_(3)^(-) ions. Besides, the high-level N/O motifs improve the surface properties of the carbon superstructures and reduce the ion migration barriers for more efficient charge storage. This paper provides insights into the design of advanced carbon-based cathodes and presents a fundamental understanding of their charge storage mechanisms.展开更多
Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and ...Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22272118,22172111,and 22309134)the Science and Technology Commission of Shanghai Municipality,China(Nos.22ZR1464100,20ZR1460300,and 19DZ2271500)+2 种基金the China Postdoctoral Science Foundation(2022M712402),the Shanghai Rising-Star Program(23YF1449200)the Zhejiang Provincial Science and Technology Project(2022C01182)the Fundamental Research Funds for the Central Universities(2023-3-YB-07)。
文摘Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.
基金National Natural Science Foundation of China under Grant No.51578463。
文摘The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with a hard combination,a numerical model is developed in this study.The indoor model test verified the accuracy of the numerical model.The influence laws of different hard combinations,train operating speeds and modes were studied and evaluated accordingly.The results show that the frequency corresponding to the peak vibration acceleration level of each floor of the superstructure property is concentrated at 10–20 Hz.The vibration response decreases in the high-frequency parts and increases in the lowfrequency parts with increasing distance from the source.Furthermore,the factors,such as train operating speed,operating mode,and hard combination type,will affect the vibration of the superstructure.The vibration response under the reversible operation of the train is greater than that of the unidirectional operation.The operating speed of the train is proportional to its vibration response.The vibration amplification area appears between the middle and the top of the superstructure at a higher train speed.Its vibration acceleration level will exceed the limit value of relevant regulations,and vibration-damping measures are required.Within the scope of application,this study provides some suggestions for constructing subway stations and superstructures.
文摘Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the requirements for applications in emerging fields such as renewable energy and electric vehicles due to limitations including a disordered structure and uncontrolled defects.With an aim of realizing devisable structures,adjustable functions,and performance breakthroughs,superstructured carbons is proposed and represent a category of carbon-based materials,characterized by precisely-built pores,networks,and interfaces.Superstructured carbons can overcome the limitations of traditional carbon materials and improve the performance of energy storage and conversion devices.We review the structure-activity relationships of superstructured carbons and recent research advances from three aspects including a precisely customized pore structure,a dense carbon network framework,and a multi-component highly coupled interface between the different components.Finally,we provide an outlook on the future development of and practical challenges in energy storage and conversion devices.
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2021ME194,2022TSGC2448,and 2023TSGC0545)the Key Technology Research and Development Program of Shandong Province(No.2021ZLGX01).
文摘The novel fabrication of multiple components and unique heterostructure can inject infinite vitality into the electromagnetic wave(EMW)attenuation field.Herein,through the self-assembly of polyimide com-plexes and catalytic chemical vapor deposition,porous carbon microflowers were synthesized accompa-nied by carbon nanotubes(CNTs).By regulating the metal ions,the composition and structure of the as-obtained hybrids are modified correspondingly,and thus the adjustable thermal management and EMW absorption capabilities are obtained.In detail,the rich pores and huge specific surface area endow the hierarchical structures with distinguished thermal insulation ability(λ<0.07).The carbon framework and CNTs are beneficial for consuming EMWs via conductive loss and defect polarization loss while reduc-ing the filling ratio and thickness.The doped heteroatoms and abundant heterointerfaces generate ample dipole polarization and interface polarization losses(supported by DFT calculation).The metal nanopar-ticles uniformly embedded in the carbon framework offer optimized impedance matching,proper de-fect polarization,and suitable magnetic loss.Accordingly,the synergy of magnetic-dielectric balance and flower-like superstructure enables FNCFN2 and NNCFN2 to accomplish remarkable microwave absorbing capacity with thin thickness(14 wt.%).Therefore,respectable specific reflection loss and specific effec-tive absorption bandwidth are acquired(215.39 dB mm^(-1) and 22.10 GHz mm^(-1),257.23 dB mm^(-1) and 22.12 GHz mm^(-1) respectively),superior to those of certain renowned carbon-based absorbers.The simu-lation results of electric field intensity distributions,power loss density,and radar cross section reduction(maximum value of 36.02 dBm2)also verify the prominent radar stealth capability.Moreover,the cus-tomizable approach can be applied to other metals to obtain fulfilling behaviors.Henceforth,this work provides profound insights into the relationship between structure and performance,and proposes an efficient path for mass-producing multifunctional and high-performance EMW absorbers with excellent thermal properties.
基金financially supported by the Program for the Development of Science and Technology of Jilin Province(Nos.YDZJ202201ZYTS313,YDZJ202201ZYTS395,20240402072GH,and 20240101004JJ)the National Natural Science Foundation of China(Nos.22201097 and 52171210)。
文摘Improving the surface atoms utilization efficiency of catalysts is extremely important for large-scale H_(2)production by electrochemical water splitting,but it remains a great challenge.Herein,we reported two kinds of Mo O_(3)-polyoxometalate hybrid nanobelt superstructures(MoO_(3)-POM HNSs,POM=PW_(12)O_(40)and Si W_(12)O_(40))using a simple hydrothermal method.Such superstructure with highly uniform nanoparticles as building blocks can expose more surface atoms and emanate increased specific surface area.The incorporated POMs generated abundant oxygen vacancies,improved the electronic mobility,and modulated the surface electronic structure of MoO_(3),allowing to optimize the H^(*)adsorption/desorption and dehydrogenation kinetics of catalyst.Notably,the as-prepared MoO_(3)-PW_(12)O_(40)HNSs electrodes not only displayed the low overpotentials of 108 mV at 10 mA/cm^(2)current density in 0.5 mol/L H_(2)SO_(4)electrolyte but also displayed excellent long-term stability.The hydrogen evolution reaction(HER)performance of MoO_(3)-POM superstructures is significantly better than that of corresponding bulk materials MoO_(3)@PW_(12)O_(40)and Mo O_(3)@Si W_(12)O_(40),and the overpotentials are about 8.3 and 4.9 times lower than that of single Mo O_(3).This work opens an avenue for designing highly surface-exposed catalysts for electrocatalytic H_(2)production and other electrochemical applications.
基金Natural Science Foundation of Xinjiang Uygur Autonomous Region,Grant/Award Number:2023D01C11National Natural Science Foundation of China,Grant/Award Numbers:22369019,U2003216+2 种基金Special Projects on Regional Collaborative Innovation-SCO Science and Technology Partnership Program,International Science and Technology Cooperation Program,Grant/Award Number:2022E01020Tianshan Talent Training Program,Grant/Award Number:2023TSYCLJ0019National Key Research and Development Program of China,Grant/Award Numbers:2022YFB4101600,2022YFB4101601。
文摘The rise of Zn-ion hybrid capacitor(ZHC)has imposed high requirements on carbon cathodes,including reasonable configuration,high specific surface area,multiscale pores,and abundant defects.To achieve this objective,a template-oriented strategy coupled with multi-heteroatom modification is proposed to precisely synthesize a three-dimensional boron/nitrogen-rich carbon nanoflake-interconnected micro/nano superstructure,referred to as BNPC.The hierarchically porous framework of BNPC shares short channels for fast Zn2+transport,increased adsorption-site accessibility,and structural robustness.Additionally,the boron/nitrogen incorporation effect significantly augments Zn2+adsorption capability and more distinctive pseudocapacitive nature,notably enhancing Zn-ion storage and transmission kinetics by performing the dual-storage mechanism of the electric double-layer capacitance and Faradaic redox process in BNPC cathode.These merits contribute to a high capacity(143.7 mAh g^(-1)at 0.2 A g^(-1))and excellent rate capability(84.5 mAh g^(-1)at 30 A g^(-1))of BNPC-based aqueous ZHC,and the ZHC still shows an ultrahigh capacity of 108.5 mAh g^(-1)even under a high BNPC mass loading of 12 mg cm^(-2).More critically,the BNPC-based flexible device also sustains notable cyclability over 30,000 cycles and low-rate self-discharge of 2.13 mV h-1 along with a preeminent energy output of 117.15 Wh kg^(-1)at a power density of 163.15Wkg^(-1),favoring a creditable applicability in modern electronics.In/ex-situ analysis and theoretical calculations elaborately elucidate the enhanced charge storage mechanism in depth.The findings offer a promising platform for the development of advanced carbon cathodes and corresponding electrochemical devices.
基金financially supported by the National Natural Science Foundation of China (Nos. 22272118, 22172111, 21905207, and 22309134)the Science and Technology Commission of Shanghai Municipality (Nos. 22ZR1464100, 20ZR1460300, and 19DZ2271500)+2 种基金China Postdoctoral Science Foundation (No. 2022M712402), Shanghai Rising-Star Program (No. 23YF1449200)Zhejiang Provincial Science and Technology Project (No. 2022C01182)the Fundamental Research Funds for the Central Universities (Nos. 22120210529 and 2023–3-YB-07)。
文摘Designing carbon materials with ideal stable hierarchical porous structures and fiexible functional properties for efficient and sustainable Zn2+ion storage still faces great challenges. Herein, the threedimensional carbon superstructures with spherical nanofiower-like structures were tailor-made by the self-assembly strategy. Specifically, organic polymer units(i.e., organic motifs) were formed by tetrachloro-p-benzoquinone(TBQ) and 2,6-diamino anthraquinone(DAQ) via a noble-metal-free catalyzed coupling reaction. Subsequently, the organic motifs assemble into spherical nanofiower-like superstructures induced by intermolecular hydrogen bonding and aromatic π-π stacking interactions. Welldesigned carbon superstructures can provide a stable backbone that effectively blocks structural stacking and collapse. Meanwhile, the hierarchical porous structures in 3D carbon superstructures provide continuous charge transport pathways to greatly shorten the ion diffusion distance, and as a result, the carbon superstructures-based zinc-ion hybrid capacitors(ZIHCs) provide a capacity of 245 m Ah/g at 0.5 A/g, a high energy density of 152 Wh/kg and an ultra-long life of 300,000 cycles at 20 A/g. The excellent electrochemical performance is also attributed to the corresponding charge storage mechanism, i.e., the alternate binding of Zn^(2+)/CF_(3)SO_(3)^(-) ions. Besides, the high-level N/O motifs improve the surface properties of the carbon superstructures and reduce the ion migration barriers for more efficient charge storage. This paper provides insights into the design of advanced carbon-based cathodes and presents a fundamental understanding of their charge storage mechanisms.
基金supported by the Australian Research Council Linkage Project(No.LP200200717)co sponsored by Newmont Corporation(United States)and Vega Industries(India)+1 种基金the Powder Diffraction Beamline at the Australia’s Nuclear Science and Technology Organisation(No.PDR19870),Australiathe Centre for Microscopy and Microanalysis at the University of Queensland(No.1366),Australia。
文摘Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.
