The performance of supercapacitors can be improved by strategically designing 2D MXene-based electrodes with excellent electrochemical properties. However, several challenges remain in developing hybrid materials base...The performance of supercapacitors can be improved by strategically designing 2D MXene-based electrodes with excellent electrochemical properties. However, several challenges remain in developing hybrid materials based on 2D MXenes due to restacking, which hinders energy storage performance. In this work, we successfully synthesized a 2D MXene/Ni-Co phosphide (MX/NCP) hybrid material for supercapacitors via a facile hydrothermal reaction followed by phosphorization. The optimized MX/NCP positive electrode showed good energy storage performance with a specific capacitance of 1754.0 F g^(-1) at 3 mA cm^(-2) in a three-electrode configuration. The synergistic effect of MXene and Ni-Co phosphide has contributed towards the enhanced charge storage performance. Furthermore, an asymmetric supercapacitor (ASC) fabricated with MX/NCP and porous nanocarbon (PNC) delivered a maximum energy density of 54.3 Wh kg^(-1) at a power density of 565.6 W kg^(-1) with a cycling stability of 93.8 % after 10,000 cycles. To evaluate the practical versatility of the ASC, a planar device was successfully fabricated making MX/NCP a promising electrode material in next-generation wearable and flexible supercapacitors.展开更多
There is a booming scientific research community looking into two-dimensional(2D)MXenes with su-perior physical and chemical characteristics that are potentially applicable in many fields.However,com-pared to energy c...There is a booming scientific research community looking into two-dimensional(2D)MXenes with su-perior physical and chemical characteristics that are potentially applicable in many fields.However,com-pared to energy conversion and storage,their applications in environment remediation have received much less attention.Hence,this review summarizes recent progresses of 2D MXenes and their derivates adopted for interdisciplinary applications with a focus on environment-related areas,aiming at promoting the diversity of MXenes and providing a refreshing background.Firstly,the properties including excellent electrical conductivity(as high as 15,100 S cm-1),large surface area(100-1,000 m2 g-1),tunable surface chemistry(-O,-OH or-F terminal groups),photothermal conversion(~100%light-to-heat efficiency)as well as kinetic and thermodynamic stability of 2D MXenes are briefly introduced.The engineering strate-gies of MXene-derived nanocomposites through the construction of heterostructures,metal/non-metal doping,the introduction of vacancies,strain engineering,and computation modelling are then followed.Finally,we emphasize current advances achieved in versatile applications including metal ions adsorp-tion,photocatalytic organics degradation and CO_(2) reduction,solar water desalination,oil/water separa-tion,and gas sensing,where engineering strategies,mechanisms,and performances of different 2D MX-ene derivates are discussed.It is envisioned that 2D MXenes will become one of the prominent nanoma-terials effective for diverse applications in the years to come.展开更多
Rechargeable batteries and supercapacitors are widely investigated as the most important electrochemical energy storage devices nowadays due to the booming energy demand for electric vehicles and hand-held electronics...Rechargeable batteries and supercapacitors are widely investigated as the most important electrochemical energy storage devices nowadays due to the booming energy demand for electric vehicles and hand-held electronics. The large surface-area-to-volume ratio and internal surface areas endow two-dimensional（2D） materials with high mobility and high energy density; therefore, 2D materials are very promising candidates for Li ion batteries and supercapacitors with comprehensive investigations. In 2011, a new kind of 2D transition metal carbides, nitrides and carbonitrides, MXene, were successfully obtained from MAX phases. Since then about 20 different kinds of MXene have been prepared. Other precursors besides MAX phases and even other methods such as chemical vapor deposition（CVD） were also applied to prepare MXene, opening new doors for the preparation of new MXene. Their 2D nature and good electronic properties ensure the inherent advantages as electrode materials for electrochemical energy storage. In this review, we summarize the recent progress in the development of MXene with emphasis on the applications to electrochemical energy storage. Also, future perspective and challenges of MXene-based materials are briefly discussed regrading electrochemical energy storage.展开更多
Lightweight,high-efficiency and low reflection electromagnetic interference(EMI)shielding polymer composites are greatly desired for addressing the challenge of ever-increasing electromagnetic pollution.Lightweight la...Lightweight,high-efficiency and low reflection electromagnetic interference(EMI)shielding polymer composites are greatly desired for addressing the challenge of ever-increasing electromagnetic pollution.Lightweight layered foam/film PVDF nanocomposites with efficient EMI shielding effectiveness and ultralow reflection power were fabricated by physical foaming.The unique layered foam/film structure was composed of PVDF/SiCnw/MXene(Ti_(3)C_(2)Tx)composite foam as absorption layer and highly conductive PVDF/MWCNT/GnPs composite film as a reflection layer.The foam layer with numerous heterogeneous interfaces developed between the SiC nanowires(SiCnw)and 2D MXene nanosheets imparted superior EM wave attenuation capability.Furthermore,the microcellular structure effectively tuned the impedance matching and prolonged the wave propagating path by internal scattering and multiple reflections.Meanwhile,the highly conductive PVDF/MWCNT/GnPs composite(~220 S m^(−1))exhibited superior reflectivity(R)of 0.95.The tailored structure in the layered foam/film PVDF nanocomposite exhibited an EMI SE of 32.6 dB and a low reflection bandwidth of 4 GHz(R<0.1)over the Kuband(12.4-18.0 GHz)at a thickness of 1.95 mm.A peak SER of 3.1×10^(-4) dB was obtained which corresponds to only 0.0022% reflection efficiency.In consequence,this study introduces a feasible approach to develop lightweight,high-efficiency EMI shielding materials with ultralow reflection for emerging applications.展开更多
Finding transition metal catalysts for effective catalytic conversion of CO to CO_(2)has attracted much attention.MXene as a new 2D layered material of early transition metal carbides,nitrides,and carbo-nitrides is a ...Finding transition metal catalysts for effective catalytic conversion of CO to CO_(2)has attracted much attention.MXene as a new 2D layered material of early transition metal carbides,nitrides,and carbo-nitrides is a robust support for achoring metal atoms.In this study,the electronic structure,geometries,thermodynamic stability,and catalytic activity of MXene (Mo_(2)CS_(2)) supported single noble metal atoms (NM=Ru,Rh,Pd,Ir,Pt and Au) have been systematically examined using first-principles calculations and ab initio molecular dynamic (AIMD) simulations.First,AIMD simulations and phonon spectra demonstrate the dynamic and thermal stabilities of Mo_(2)CS_(2)monolayer.Three likely reaction pathways,LangmuirHinshelwood (LH),Eley-Rideal (ER),and Termolecular Eley–Rideal (TER) for CO oxidation on the Ru1-and Ir_(1)@Mo_(2)CS_(2)SACs,have been studied in detail.It is found that CO oxidation mainly proceeds via the TER mechanism under mild reaction conditions.The corresponding rate-determining steps are the dissociation of the intermediate (OCO-Ru_(1)-OCO) and formation of OCO-Ir_(1)-OCO intermediate.The downshift d-band center of Ru1-and Ir_(1)@Mo_(2)CS_(2)help to enhance activity and improve catalytst stability.Moreover,a microkinetic study predicts a maximum CO oxidation rate of 4.01×10^(2)s^(-1)and 4.15×10^(3)s^(-1)(298.15K) following the TER pathway for the Ru_(1)-and Ir_(1)@Mo_(2)CS_(2)catalysts,respectively.This work provides guideline for fabricating and designing highly efficient SACs with superb catalyts using MXene materials.展开更多
Threshold switching(TS) memristors can be used as artificial neurons in neuromorphic systems due to their continuous conductance modulation, scalable and energy-efficient properties. In this paper, we propose a low po...Threshold switching(TS) memristors can be used as artificial neurons in neuromorphic systems due to their continuous conductance modulation, scalable and energy-efficient properties. In this paper, we propose a low power artificial neuron based on the Ag/MXene/GST/Pt device with excellent TS characteristics, including a low set voltage(0.38 V)and current(200 nA), an extremely steep slope(< 0.1 m V/dec), and a relatively large off/on ratio(> 10^(3)). Besides, the characteristics of integrate and fire neurons that are indispensable for spiking neural networks have been experimentally demonstrated. Finally, its memristive mechanism is interpreted through the first-principles calculation depending on the electrochemical metallization effect.展开更多
High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attr...High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.展开更多
MXene-based 2D heterostructures have emerged as a highly promising area of research in the field of energy storage and conversion,owing to their exceptional properties and versatility.This comprehensive review aims to...MXene-based 2D heterostructures have emerged as a highly promising area of research in the field of energy storage and conversion,owing to their exceptional properties and versatility.This comprehensive review aims to highlight the recent advancements and challenges associated with tailoring MXene-based heterostructures.The review focuses on the progress made in the past decade regarding 2D/2D MXene-based heterostructures for energy storage/conversion.The influence of interfacial interactions,electronic conductivity,ion diffusion pathways,and surface chemistry on the performance of these heterostructures in supercapacitors,batteries,and water-splitting reactions have been critically examined.By considering these factors,researchers gain insights into the design principles and optimization strategies for MXene-based heterostructures.By understanding the progress made and the existing challenges,researchers can further explore the vast potential of MXene heterostructures and contribute to the development of next-generation energy storage and conversion technologies.展开更多
An increased demand for iron is a hallmark of cancer cells and is thought necessary to promote high cell proliferation,tumor progression and metastasis.This makes iron metabolism an attractive therapeutic target.Unfor...An increased demand for iron is a hallmark of cancer cells and is thought necessary to promote high cell proliferation,tumor progression and metastasis.This makes iron metabolism an attractive therapeutic target.Unfortunately,current iron-based therapeutic strategies often lack effectiveness and can elicit off-target toxicities.We report here a dual-therapeutic prodrug,DOXjade,that allows for iron chelation chemo-photothermal cancer therapy.This prodrug takes advantage of the clinically approved iron chelator deferasirox(ExJade®)and the topoisomerase 2 inhibitor,doxorubicin(DOX).Loading DOXjade onto ultrathin 2D Ti_(3)C_(2) MXene nanosheets produces a construct,Ti_(3)C_(2)-PVP@DOXjade,that allows the iron chelation and chemotherapeutic functions of DOXjade to be photo-activated at the tumor sites,while potentiating a robust photothermal effect with photothermal conversion efficiencies of up to 40%.Antitumor mechanistic investigations reveal that upon activation,Ti_(3)C_(2)-PVP@DOXjade serves to promote apoptotic cell death and downregulate the iron depletion-induced iron transferrin receptor(TfR).A tumor pH-responsive iron chelation/photothermal/chemotherapy antitumor effect was achieved both in vitro and in vivo.The results of this study highlight what may constitute a promising iron chelation-based phototherapeutic approach to cancer therapy.展开更多
Two-dimensional(2 D)material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity,good hydrophilicity and high volumetric capacity.However,the sel...Two-dimensional(2 D)material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity,good hydrophilicity and high volumetric capacity.However,the self-restocking of ultra-thin 2 D materials seriously hinders these performances,which significantly inhibits the full exploitation of MXenes in the field of energy storage.To solve this issue,a strategy to prepare delaminated Ti_(3)C_(2)T_(x)(MXene)nanoflakes/reduced graphene oxide(r GO)composites is proposed using the electrostatic self-assembly between positively charged Ti_(3)C_(2)T_(x) with tetrabutylammonium ion(TBA+)modification and negatively charged graphene.The nanoflakes of Ti_(3)C_(2)T_(x)/rGO are well dispersed and arranged in a face-to-face structure to effectively alleviate the self-restacking and provide more electroactive sites for accessible of electrolyte ions.The prepared delaminated Ti_(3)C_(2)T_(x)/r GO anode shows a high reversible capacity up to 1394 m Ah g^(-1) at a current density of 50 m A g^(-1).Moreover,a lithium-ion capacitor(LIC)was assembled with delaminated Ti_(3)C_(2)T_(x)/r GO anode and activated carbon(AC)cathode which can exhibit a specific capacity of 70.7 F g^(-1) at a current density of 0.1 A g^(-1) and deliver an ultrahigh energy density of 114 Wh kg^(-1) at a relatively high power density of 3125 W kg^(-1).These good electrochemical performances demonstrate the potential of delaminated Ti_(3)C_(2)T_(x)/r GO as an anode material for lithium-ion capacitors.展开更多
MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability a...MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability and catalytic properties of a non-noble metal single-atom catalyst(SAC)with single Co atom anchored on MXene materials of Mo_(2)CS_(2).The Co adatom anchored on top of the Mo atom of this MXene is found to be rather stable,and this SAC is appropriate for CO oxidation.The charge transfers from the surface to the adsorbed CO and O2 play a significant role in the activation of these molecules on Co_(1)/Mo_(2)CS_(2).With this catalyst,the Eley-Rideal(ER),Langmuir-Hinshelwood(LH),and Termolecular Eley-Rideal(TER)mechanisms are explored for CO oxidation.We find that,while all the three mechanisms are feasible at low temperature,Co_(1)/Mo_(2)CS_(2) possesses higher catalytic activity for CO oxidation through the TER mechanism that features an intriguing OC(OO)CO intermediate(IM)adsorbed on Co single atom.The calculated activation energy barriers of the rate-limiting step are 0.67 eV(TER),0.78 eV(LH)and 0.88 eV(ER),respectively.The present study illustrates that it is promising to develop and design low-cost,non-noble metal SACs using MXene types of 2D materials.展开更多
Osmotic energy from the ocean,also called blue energy,serves as a clean,renewable,and vast energy source for the energy demands of the world.Reverse electrodialysis-based blue energy harvesting via ion-selective membr...Osmotic energy from the ocean,also called blue energy,serves as a clean,renewable,and vast energy source for the energy demands of the world.Reverse electrodialysis-based blue energy harvesting via ion-selective membranes,by the regulation and manipulation of directional ion transport,has been greatly developed recently.In particular,light has been employed to enhance directional ion transport for energy conversion through an increase in photo-induced surface charge.Here,the authors demonstrate a novel nanofluidic regulation strategy based on the phenomenon of light-induced heat-driven active ion transport through the lamellar MXene membrane.Due to the great light-induced heat effect,a temperature gradient appears as soon as illumination is applied to an off-center position,inducing an actively temperature gradient-driven ionic species transport.By employing this phenomenon,the authors conducted light-induced heat-enhanced osmotic energy conversion and doubled the osmotic energy conversion power density.This study has extended the scope of light-enhanced osmotic energy conversion and could further bring other photothermal materials into this field.Furthermore,the proposed system provides a new avenue of light-controlled ionic transport for ion gathering,desalination,and energy conversion applications.展开更多
Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect...Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect their physical properties.In this study,a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed.The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)C.On the basis of this mechanism,the room-temperature ferromagnetism of two-dimensional few-layered Cr_(2)CT_(x)MXenes,which has a specific saturation magnetization of~0.26 emu/g and a Curie temperature of>353 K,is experimentally verified.The calculated electronic band structure implies that the semimetal Cr_(2)CT_(x)MXene has a band gap of 0.75 eV.This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.展开更多
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korean Govern-ment(MSIT)(Nos.RS-2023-00217581 and RS-2024-00345983).
文摘The performance of supercapacitors can be improved by strategically designing 2D MXene-based electrodes with excellent electrochemical properties. However, several challenges remain in developing hybrid materials based on 2D MXenes due to restacking, which hinders energy storage performance. In this work, we successfully synthesized a 2D MXene/Ni-Co phosphide (MX/NCP) hybrid material for supercapacitors via a facile hydrothermal reaction followed by phosphorization. The optimized MX/NCP positive electrode showed good energy storage performance with a specific capacitance of 1754.0 F g^(-1) at 3 mA cm^(-2) in a three-electrode configuration. The synergistic effect of MXene and Ni-Co phosphide has contributed towards the enhanced charge storage performance. Furthermore, an asymmetric supercapacitor (ASC) fabricated with MX/NCP and porous nanocarbon (PNC) delivered a maximum energy density of 54.3 Wh kg^(-1) at a power density of 565.6 W kg^(-1) with a cycling stability of 93.8 % after 10,000 cycles. To evaluate the practical versatility of the ASC, a planar device was successfully fabricated making MX/NCP a promising electrode material in next-generation wearable and flexible supercapacitors.
基金supported by the National Natural Science Foundation of China(Nos.22076050,51978288 and 52200016).
文摘There is a booming scientific research community looking into two-dimensional(2D)MXenes with su-perior physical and chemical characteristics that are potentially applicable in many fields.However,com-pared to energy conversion and storage,their applications in environment remediation have received much less attention.Hence,this review summarizes recent progresses of 2D MXenes and their derivates adopted for interdisciplinary applications with a focus on environment-related areas,aiming at promoting the diversity of MXenes and providing a refreshing background.Firstly,the properties including excellent electrical conductivity(as high as 15,100 S cm-1),large surface area(100-1,000 m2 g-1),tunable surface chemistry(-O,-OH or-F terminal groups),photothermal conversion(~100%light-to-heat efficiency)as well as kinetic and thermodynamic stability of 2D MXenes are briefly introduced.The engineering strate-gies of MXene-derived nanocomposites through the construction of heterostructures,metal/non-metal doping,the introduction of vacancies,strain engineering,and computation modelling are then followed.Finally,we emphasize current advances achieved in versatile applications including metal ions adsorp-tion,photocatalytic organics degradation and CO_(2) reduction,solar water desalination,oil/water separa-tion,and gas sensing,where engineering strategies,mechanisms,and performances of different 2D MX-ene derivates are discussed.It is envisioned that 2D MXenes will become one of the prominent nanoma-terials effective for diverse applications in the years to come.
基金supported by Tianjin Municipal Science and Technology Commission(16PTSYJC00010)in China
文摘Rechargeable batteries and supercapacitors are widely investigated as the most important electrochemical energy storage devices nowadays due to the booming energy demand for electric vehicles and hand-held electronics. The large surface-area-to-volume ratio and internal surface areas endow two-dimensional（2D） materials with high mobility and high energy density; therefore, 2D materials are very promising candidates for Li ion batteries and supercapacitors with comprehensive investigations. In 2011, a new kind of 2D transition metal carbides, nitrides and carbonitrides, MXene, were successfully obtained from MAX phases. Since then about 20 different kinds of MXene have been prepared. Other precursors besides MAX phases and even other methods such as chemical vapor deposition（CVD） were also applied to prepare MXene, opening new doors for the preparation of new MXene. Their 2D nature and good electronic properties ensure the inherent advantages as electrode materials for electrochemical energy storage. In this review, we summarize the recent progress in the development of MXene with emphasis on the applications to electrochemical energy storage. Also, future perspective and challenges of MXene-based materials are briefly discussed regrading electrochemical energy storage.
基金the financial support of NSERC(Discovery Grant RGPIN-2015-03985).
文摘Lightweight,high-efficiency and low reflection electromagnetic interference(EMI)shielding polymer composites are greatly desired for addressing the challenge of ever-increasing electromagnetic pollution.Lightweight layered foam/film PVDF nanocomposites with efficient EMI shielding effectiveness and ultralow reflection power were fabricated by physical foaming.The unique layered foam/film structure was composed of PVDF/SiCnw/MXene(Ti_(3)C_(2)Tx)composite foam as absorption layer and highly conductive PVDF/MWCNT/GnPs composite film as a reflection layer.The foam layer with numerous heterogeneous interfaces developed between the SiC nanowires(SiCnw)and 2D MXene nanosheets imparted superior EM wave attenuation capability.Furthermore,the microcellular structure effectively tuned the impedance matching and prolonged the wave propagating path by internal scattering and multiple reflections.Meanwhile,the highly conductive PVDF/MWCNT/GnPs composite(~220 S m^(−1))exhibited superior reflectivity(R)of 0.95.The tailored structure in the layered foam/film PVDF nanocomposite exhibited an EMI SE of 32.6 dB and a low reflection bandwidth of 4 GHz(R<0.1)over the Kuband(12.4-18.0 GHz)at a thickness of 1.95 mm.A peak SER of 3.1×10^(-4) dB was obtained which corresponds to only 0.0022% reflection efficiency.In consequence,this study introduces a feasible approach to develop lightweight,high-efficiency EMI shielding materials with ultralow reflection for emerging applications.
基金supported by the National Natural Science Foundation of China (Nos. 11874141 and 22033005)the Henan Overseas Expertise Introduction Center for Discipline Innovation (No. CXJD2019005)+1 种基金the Guangdong Provincial Key Laboratory of Catalysis (No. 2020B121201002)funding support from the Researchers Supporting Project number (No. RSP-2021/399), King Saud University, Riyadh, Saudi Arabia。
文摘Finding transition metal catalysts for effective catalytic conversion of CO to CO_(2)has attracted much attention.MXene as a new 2D layered material of early transition metal carbides,nitrides,and carbo-nitrides is a robust support for achoring metal atoms.In this study,the electronic structure,geometries,thermodynamic stability,and catalytic activity of MXene (Mo_(2)CS_(2)) supported single noble metal atoms (NM=Ru,Rh,Pd,Ir,Pt and Au) have been systematically examined using first-principles calculations and ab initio molecular dynamic (AIMD) simulations.First,AIMD simulations and phonon spectra demonstrate the dynamic and thermal stabilities of Mo_(2)CS_(2)monolayer.Three likely reaction pathways,LangmuirHinshelwood (LH),Eley-Rideal (ER),and Termolecular Eley–Rideal (TER) for CO oxidation on the Ru1-and Ir_(1)@Mo_(2)CS_(2)SACs,have been studied in detail.It is found that CO oxidation mainly proceeds via the TER mechanism under mild reaction conditions.The corresponding rate-determining steps are the dissociation of the intermediate (OCO-Ru_(1)-OCO) and formation of OCO-Ir_(1)-OCO intermediate.The downshift d-band center of Ru1-and Ir_(1)@Mo_(2)CS_(2)help to enhance activity and improve catalytst stability.Moreover,a microkinetic study predicts a maximum CO oxidation rate of 4.01×10^(2)s^(-1)and 4.15×10^(3)s^(-1)(298.15K) following the TER pathway for the Ru_(1)-and Ir_(1)@Mo_(2)CS_(2)catalysts,respectively.This work provides guideline for fabricating and designing highly efficient SACs with superb catalyts using MXene materials.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61804079 and 61964012)the open research fund of the National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology (Grant No.KFJJ20200102)+2 种基金the Natural Science Foundation of Jiangsu Province of China (Grant Nos.BK20211273 and BZ2021031)the Nanjing University of Posts and Telecommunications (Grant No.NY220112)the Foundation of Jiangxi Science and Technology Department (Grant No.20202ACBL21200)。
文摘Threshold switching(TS) memristors can be used as artificial neurons in neuromorphic systems due to their continuous conductance modulation, scalable and energy-efficient properties. In this paper, we propose a low power artificial neuron based on the Ag/MXene/GST/Pt device with excellent TS characteristics, including a low set voltage(0.38 V)and current(200 nA), an extremely steep slope(< 0.1 m V/dec), and a relatively large off/on ratio(> 10^(3)). Besides, the characteristics of integrate and fire neurons that are indispensable for spiking neural networks have been experimentally demonstrated. Finally, its memristive mechanism is interpreted through the first-principles calculation depending on the electrochemical metallization effect.
基金Funding from the Australian Research Council Centre of Excellence Scheme(CE 140100012)the funding from National Natural Science Foundation of China(51502206)+1 种基金the CSC scholarship from the Ministry of Education of PR Chinathe support of the CSC scholarship from the Ministry of Education of PR China
文摘High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.
基金supported by the Hong Kong Re-search Grants Council(Project No.CityU 11218420).
文摘MXene-based 2D heterostructures have emerged as a highly promising area of research in the field of energy storage and conversion,owing to their exceptional properties and versatility.This comprehensive review aims to highlight the recent advancements and challenges associated with tailoring MXene-based heterostructures.The review focuses on the progress made in the past decade regarding 2D/2D MXene-based heterostructures for energy storage/conversion.The influence of interfacial interactions,electronic conductivity,ion diffusion pathways,and surface chemistry on the performance of these heterostructures in supercapacitors,batteries,and water-splitting reactions have been critically examined.By considering these factors,researchers gain insights into the design principles and optimization strategies for MXene-based heterostructures.By understanding the progress made and the existing challenges,researchers can further explore the vast potential of MXene heterostructures and contribute to the development of next-generation energy storage and conversion technologies.
基金supported by the National Natural Science Foundation of China(Grant No.11904239,Y.W.W)the Creative Research Initiative of National Research Foundation of Korea(NRF)(CRI project No.2018R1A3B1052702,J.S.K.)+1 种基金Initial support for the work in Austin came from the National Institutes of Health(CA 68682 to J.L.S.)with subsequent funding from the Robert A.Welch Foundation(F-0018 to J.L.S.)supported by Brain Pool Program through the funded by the Ministry of Science and ICT(Grant No.2020H1D3A1A02080172,M.L.).
文摘An increased demand for iron is a hallmark of cancer cells and is thought necessary to promote high cell proliferation,tumor progression and metastasis.This makes iron metabolism an attractive therapeutic target.Unfortunately,current iron-based therapeutic strategies often lack effectiveness and can elicit off-target toxicities.We report here a dual-therapeutic prodrug,DOXjade,that allows for iron chelation chemo-photothermal cancer therapy.This prodrug takes advantage of the clinically approved iron chelator deferasirox(ExJade®)and the topoisomerase 2 inhibitor,doxorubicin(DOX).Loading DOXjade onto ultrathin 2D Ti_(3)C_(2) MXene nanosheets produces a construct,Ti_(3)C_(2)-PVP@DOXjade,that allows the iron chelation and chemotherapeutic functions of DOXjade to be photo-activated at the tumor sites,while potentiating a robust photothermal effect with photothermal conversion efficiencies of up to 40%.Antitumor mechanistic investigations reveal that upon activation,Ti_(3)C_(2)-PVP@DOXjade serves to promote apoptotic cell death and downregulate the iron depletion-induced iron transferrin receptor(TfR).A tumor pH-responsive iron chelation/photothermal/chemotherapy antitumor effect was achieved both in vitro and in vivo.The results of this study highlight what may constitute a promising iron chelation-based phototherapeutic approach to cancer therapy.
基金supported by the National Natural Science Foundation of China (51677182 and 51822706)the Dalian National Laboratory for Clean Energy (DNL) Cooperation Fund, CAS (DNL201915 and DNL201912)+1 种基金the Beijing Municipal Science and Technology Commission (Z181100000118006)the Key Research Program of Frontier Sciences, CAS (ZDBS-LY-JSC047)。
文摘Two-dimensional(2 D)material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity,good hydrophilicity and high volumetric capacity.However,the self-restocking of ultra-thin 2 D materials seriously hinders these performances,which significantly inhibits the full exploitation of MXenes in the field of energy storage.To solve this issue,a strategy to prepare delaminated Ti_(3)C_(2)T_(x)(MXene)nanoflakes/reduced graphene oxide(r GO)composites is proposed using the electrostatic self-assembly between positively charged Ti_(3)C_(2)T_(x) with tetrabutylammonium ion(TBA+)modification and negatively charged graphene.The nanoflakes of Ti_(3)C_(2)T_(x)/rGO are well dispersed and arranged in a face-to-face structure to effectively alleviate the self-restacking and provide more electroactive sites for accessible of electrolyte ions.The prepared delaminated Ti_(3)C_(2)T_(x)/r GO anode shows a high reversible capacity up to 1394 m Ah g^(-1) at a current density of 50 m A g^(-1).Moreover,a lithium-ion capacitor(LIC)was assembled with delaminated Ti_(3)C_(2)T_(x)/r GO anode and activated carbon(AC)cathode which can exhibit a specific capacity of 70.7 F g^(-1) at a current density of 0.1 A g^(-1) and deliver an ultrahigh energy density of 114 Wh kg^(-1) at a relatively high power density of 3125 W kg^(-1).These good electrochemical performances demonstrate the potential of delaminated Ti_(3)C_(2)T_(x)/r GO as an anode material for lithium-ion capacitors.
基金the National Natural Science Foundation of China(21590792,91426302,and 21433005)Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)+1 种基金the National Science Basic Research Program of Shaanxi Province(2019JM-226)the financial and technical support from the Research Center for Advanced Materials Science(RCAMS)at King Khalid University through the Grant(RCAMS/KKU/014-20)。
文摘MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability and catalytic properties of a non-noble metal single-atom catalyst(SAC)with single Co atom anchored on MXene materials of Mo_(2)CS_(2).The Co adatom anchored on top of the Mo atom of this MXene is found to be rather stable,and this SAC is appropriate for CO oxidation.The charge transfers from the surface to the adsorbed CO and O2 play a significant role in the activation of these molecules on Co_(1)/Mo_(2)CS_(2).With this catalyst,the Eley-Rideal(ER),Langmuir-Hinshelwood(LH),and Termolecular Eley-Rideal(TER)mechanisms are explored for CO oxidation.We find that,while all the three mechanisms are feasible at low temperature,Co_(1)/Mo_(2)CS_(2) possesses higher catalytic activity for CO oxidation through the TER mechanism that features an intriguing OC(OO)CO intermediate(IM)adsorbed on Co single atom.The calculated activation energy barriers of the rate-limiting step are 0.67 eV(TER),0.78 eV(LH)and 0.88 eV(ER),respectively.The present study illustrates that it is promising to develop and design low-cost,non-noble metal SACs using MXene types of 2D materials.
基金This study was supported by the National Key R&D Program of China(nos.2017YFA0206904 and 2017YFA0206900)the National Natural Science Foundation of China(nos.21625303,21905287,51673206,and 21988102)+2 种基金the Beijing Natural Science Foundation(no.2194088)the Strategic Priority Research Program of the Chinese Academy of Science(no.XDA21010213)the Key Research Program of the Chinese Academy of Sciences(no.QYZDY-SSW-SLH014).
文摘Osmotic energy from the ocean,also called blue energy,serves as a clean,renewable,and vast energy source for the energy demands of the world.Reverse electrodialysis-based blue energy harvesting via ion-selective membranes,by the regulation and manipulation of directional ion transport,has been greatly developed recently.In particular,light has been employed to enhance directional ion transport for energy conversion through an increase in photo-induced surface charge.Here,the authors demonstrate a novel nanofluidic regulation strategy based on the phenomenon of light-induced heat-driven active ion transport through the lamellar MXene membrane.Due to the great light-induced heat effect,a temperature gradient appears as soon as illumination is applied to an off-center position,inducing an actively temperature gradient-driven ionic species transport.By employing this phenomenon,the authors conducted light-induced heat-enhanced osmotic energy conversion and doubled the osmotic energy conversion power density.This study has extended the scope of light-enhanced osmotic energy conversion and could further bring other photothermal materials into this field.Furthermore,the proposed system provides a new avenue of light-controlled ionic transport for ion gathering,desalination,and energy conversion applications.
基金supported financially by the Beijing Natural Science Foundation(Nos.2212046,2234093,and L211001)the National Natural Science Foundation of China(Nos.51871011 and 51572017)+1 种基金the Research Fund for Commercialization of Major Scientific and Technological Achievements of Hebei Province(No.22281006Z)the Beijing Government Funds for the Constructive Project of Central Universities.
文摘Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect their physical properties.In this study,a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed.The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)C.On the basis of this mechanism,the room-temperature ferromagnetism of two-dimensional few-layered Cr_(2)CT_(x)MXenes,which has a specific saturation magnetization of~0.26 emu/g and a Curie temperature of>353 K,is experimentally verified.The calculated electronic band structure implies that the semimetal Cr_(2)CT_(x)MXene has a band gap of 0.75 eV.This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.
