MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical str...MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical strength,etc.This review begins by presenting MXenes,providing insights into their structural characteristics,synthesis methods,and surface functional groups.The review covers a thorough analysis of MXene surface properties,including surface chemistry and termination group impacts.The properties of MXenes are influenced by their synthesis,which can be fluorine-based or fluorinedependent.Fluorine-based synthesis techniques involve etching with fluorine-based reagents,mainly including HF or LiF/HCl,while fluorine-free methods include electrochemical etching,chemical vapor deposition(CVD),alkaline etching,Lewis acid-based etching,etc.These techniques result in the emergence of functional groups such as-F,-O,-OH,-Cl,etc.on the MXenes surface,depending on the synthesis method used.Properties of MXenes,such as electrical conductivity,electronic properties,catalytic activity,magnetic properties,mechanical strength,and chemical and thermal stability,are examined,and the role of functional groups in determining these properties is explored.The review delves into the diverse applications of MXenes,encompassing supercapacitors,battery materials,hydrogen storage,fuel cells,electromagnetic interference(EMI) shielding,pollutant removal,water purification,flexible electronics,sensors,additive manufacturing,catalysis,biomedical and healthcare fields,etc.Finally,this article outlines the challenges and opportunities in the current and future development of MXenes research,addressing various aspects such as synthesis scalability,etching challenges,and multifunctionality,and exploring novel applications.The review concludes with future prospects and conclusions envisioning the impact of MXenes on future technologies and innovation.展开更多
Nanofluidic channels inspired by electric eels open a new era of efficient harvesting of clean blue osmotic energy from salinity gradients.Limited by less charge and weak ion selectivity of the raw material itself,ene...Nanofluidic channels inspired by electric eels open a new era of efficient harvesting of clean blue osmotic energy from salinity gradients.Limited by less charge and weak ion selectivity of the raw material itself,energy conversion through nanofluidic channels is still facing considerable challenges.Here,a facile and efficient strategy to enhance osmotic energy harvesting based on drastically increasing surface charge density of MXenes subnanochannels via oxygen plasma is proposed.This plasma could break Ti–C bonds in the MXenes subnanochannels and effectively facilitate the formation of more Ti–O,C═O,O–OH,and rutile with a stronger negative charge and work function,which leads the surface potential of MXenes membrane to increase from 205 to 430 mV.This significant rise of surface charge endows the MXenes membrane with high cation selectivity,which could make the output power density of the MXenes membrane increase by 248.2%,reaching a high value of 5.92Wm^(−2) in the artificial sea‐river water system.Furthermore,with the assistance of low‐quality heat at 50℃,the osmotic power is enhanced to an ultrahigh value of 9.68Wm^(−2),which outperforms those of the state‐of‐the‐art two‐dimensional(2D)nanochannel membranes.This exciting breakthrough demonstrates the enormous potential of the facile plasma‐treated 2D membranes for osmotic energy harvesting.展开更多
Transition metal carbides and nitrides(MXenes)are crystal nanomaterials with a number of surface functional groups such as fluorine,hydroxyl,and oxygen,which can be used as carriers for proteins and drugs.MXenes have ...Transition metal carbides and nitrides(MXenes)are crystal nanomaterials with a number of surface functional groups such as fluorine,hydroxyl,and oxygen,which can be used as carriers for proteins and drugs.MXenes have excellent biocompatibility,electrical conductivity,surface hydrophilicity,mechanical properties and easy surface modification.However,at present,the stability of most MXenes needs to be improved,and more synthesis methods need to be explored.MXenes are good substrates for nerve cell regeneration and nerve reconstruction,which have broad application prospects in the repair of nervous system injury.Regarding the application of MXenes in neuroscience,mainly at the cellular level,the long-term in vivo biosafety and effects also need to be further explored.This review focuses on the progress of using MXenes in nerve regeneration over the last few years;discussing preparation of MXenes and their biocompatibility with different cells as well as the regulation by MXenes of nerve cell regeneration in two-dimensional and three-dimensional environments in vitro.MXenes have great potential in regulating the proliferation,differentiation,and maturation of nerve cells and in promoting regeneration and recovery after nerve injury.In addition,this review also presents the main challenges during optimization processes,such as the preparation of stable MXenes and long-term in vivo biosafety,and further discusses future directions in neural tissue engineering.展开更多
The increasing focus on electrocatalysis for sustainable hydrogen(H_(2))production has prompted significant interest in MXenes,a class of two-dimensional(2D)materials comprising metal carbides,carbonitrides,and nitrid...The increasing focus on electrocatalysis for sustainable hydrogen(H_(2))production has prompted significant interest in MXenes,a class of two-dimensional(2D)materials comprising metal carbides,carbonitrides,and nitrides.These materials exhibit intriguing chemical and physical properties,including excellent electrical conductivity and a large surface area,making them attractive candidates for the hydrogen evolution reaction(HER).This scientific review explores recent advancements in MXene-based electrocatalysts for HER kinetics.It discusses various compositions,functionalities,and explicit design principles while providing a comprehensive overview of synthesis methods,exceptional properties,and electro-catalytic approaches for H_(2) production via electrochemical reactions.Furthermore,challenges and future prospects in designing MXenes-based electrocatalysts with enhanced kinetics are highlighted,emphasizing the potential of incorporating different metals to expand the scope of electrochemical reactions.This review suggests possible efforts for developing advanced MXenes-based electrocatalysts,particularly for efficient H_(2) generation through electrochemical water-splitting reactions..展开更多
MXene has garnered widespread recognition in the scientific com-munity due to its remarkable properties,including excellent thermal stability,high conductivity,good hydrophilicity and dispersibility,easy processabilit...MXene has garnered widespread recognition in the scientific com-munity due to its remarkable properties,including excellent thermal stability,high conductivity,good hydrophilicity and dispersibility,easy processability,tunable surface properties,and admirable flexibility.MXenes have been categorized into different families based on the number of M and X layers in M_(n+1)X_(n),such as M_(2)X,M_(3)X_(2),M_(4)X_(3),and,recently,M_(5)X_(4).Among these families,M_(2)X and M_(3)X_(2),par-ticularly Ti_(3)C_(2),have been greatly explored while limited studies have been given to M_(5)X_(4)MXene synthesis.Meanwhile,studies on the M_(4)X_(3)MXene family have developed recently,hence,demanding a compilation of evaluated studies.Herein,this review provides a systematic overview of the latest advancements in M_(4)X_(3)MXenes,focusing on their properties and applications in energy storage devices.The objective of this review is to provide guidance to researchers on fostering M_(4)X_(3)MXene-based nanomaterials,not only for energy storage devices but also for broader applications.展开更多
Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural mo...Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural movements of living organisms,aiming to attain enhanced flexibility,adaptability,and versatility.On the other hand,angle-independent structural color has been achieved through innovative design strategies and engineering approaches.By carefully controlling the size,shape,and arrangement of nanostructures,researchers have been able to create materials exhibiting consistent colors regardless of the viewing angle.One promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical,electrical,and optical properties.The integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting possibilities.Overcoming material compatibility issues,improving color reproducibility,scalability,durability,power supply efficiency,and cost-effectiveness will play vital roles in advancing these technologies.This perspective appraises the development of bioinspired MXene-centered soft actuators with angleindependent structural color in soft robotics.展开更多
Finding appropriate photocatalysts for solar-driven water(H_(2)O)splitting to generate hydrogen(H_(2))fuel is a challenging task,particularly when guided by conventional trial-and-error experimental methods.Here,densi...Finding appropriate photocatalysts for solar-driven water(H_(2)O)splitting to generate hydrogen(H_(2))fuel is a challenging task,particularly when guided by conventional trial-and-error experimental methods.Here,density functional theory(DFT)is used to explore the MXenes photocatalytic properties,an emerging family of two-dimensional(2D)transition metal carbides and nitrides with chemical formula M_(n+1)X_(n)T_(x),known to be semiconductors when having T_(x)terminations.More than 4,000 MXene structures have been screened,considering different compositional(M,X,T_(x),and n)and structural(stacking and termination position)factors,to find suitable MXenes with a bandgap in the visible region and band edges that align with the water-splitting half-reaction potentials.Results from bandgap analysis show how,in general,MXenes with n=1 and transition metals from group III present the most cases with bandgap and promising sizes,with C-MXenes being superior to N-MXenes.From band alignment calculations of candidate systems with a bandgap larger than 1.23 eV,the minimum required for a water-splitting process,Sc_(2)CT_(2),Y_(2)CT_(2)(T_(x)=Cl,Br,S,and Se)and Y_(2)CI_(2)are highlighted as adequate photocatalysts.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2020R1A6A1A03043435 and 2020R1A2C1099862)supported by the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korean Government(MOTIE)(P0012451,The Competency Development Program for Industry Specialist)。
文摘MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical strength,etc.This review begins by presenting MXenes,providing insights into their structural characteristics,synthesis methods,and surface functional groups.The review covers a thorough analysis of MXene surface properties,including surface chemistry and termination group impacts.The properties of MXenes are influenced by their synthesis,which can be fluorine-based or fluorinedependent.Fluorine-based synthesis techniques involve etching with fluorine-based reagents,mainly including HF or LiF/HCl,while fluorine-free methods include electrochemical etching,chemical vapor deposition(CVD),alkaline etching,Lewis acid-based etching,etc.These techniques result in the emergence of functional groups such as-F,-O,-OH,-Cl,etc.on the MXenes surface,depending on the synthesis method used.Properties of MXenes,such as electrical conductivity,electronic properties,catalytic activity,magnetic properties,mechanical strength,and chemical and thermal stability,are examined,and the role of functional groups in determining these properties is explored.The review delves into the diverse applications of MXenes,encompassing supercapacitors,battery materials,hydrogen storage,fuel cells,electromagnetic interference(EMI) shielding,pollutant removal,water purification,flexible electronics,sensors,additive manufacturing,catalysis,biomedical and healthcare fields,etc.Finally,this article outlines the challenges and opportunities in the current and future development of MXenes research,addressing various aspects such as synthesis scalability,etching challenges,and multifunctionality,and exploring novel applications.The review concludes with future prospects and conclusions envisioning the impact of MXenes on future technologies and innovation.
基金National Natural Science Foundation of China,Grant/Award Number:52175174China Postdoctoral Science Foundation,Grant/Award Number:2022M721791National Key Research and Development Program of China,Grant/Award Number:2020YFA0711003。
文摘Nanofluidic channels inspired by electric eels open a new era of efficient harvesting of clean blue osmotic energy from salinity gradients.Limited by less charge and weak ion selectivity of the raw material itself,energy conversion through nanofluidic channels is still facing considerable challenges.Here,a facile and efficient strategy to enhance osmotic energy harvesting based on drastically increasing surface charge density of MXenes subnanochannels via oxygen plasma is proposed.This plasma could break Ti–C bonds in the MXenes subnanochannels and effectively facilitate the formation of more Ti–O,C═O,O–OH,and rutile with a stronger negative charge and work function,which leads the surface potential of MXenes membrane to increase from 205 to 430 mV.This significant rise of surface charge endows the MXenes membrane with high cation selectivity,which could make the output power density of the MXenes membrane increase by 248.2%,reaching a high value of 5.92Wm^(−2) in the artificial sea‐river water system.Furthermore,with the assistance of low‐quality heat at 50℃,the osmotic power is enhanced to an ultrahigh value of 9.68Wm^(−2),which outperforms those of the state‐of‐the‐art two‐dimensional(2D)nanochannel membranes.This exciting breakthrough demonstrates the enormous potential of the facile plasma‐treated 2D membranes for osmotic energy harvesting.
基金supported by grants from the National Key R&D Program of China,Nos.2021YFA1101300,2021YFA1101803,2020YFA0112503the National Natural Science Foundation of China,Nos.82030029,81970882,92149304Science and Technology Department of Sichuan Province,No.2021YFS0371(all to RC)。
文摘Transition metal carbides and nitrides(MXenes)are crystal nanomaterials with a number of surface functional groups such as fluorine,hydroxyl,and oxygen,which can be used as carriers for proteins and drugs.MXenes have excellent biocompatibility,electrical conductivity,surface hydrophilicity,mechanical properties and easy surface modification.However,at present,the stability of most MXenes needs to be improved,and more synthesis methods need to be explored.MXenes are good substrates for nerve cell regeneration and nerve reconstruction,which have broad application prospects in the repair of nervous system injury.Regarding the application of MXenes in neuroscience,mainly at the cellular level,the long-term in vivo biosafety and effects also need to be further explored.This review focuses on the progress of using MXenes in nerve regeneration over the last few years;discussing preparation of MXenes and their biocompatibility with different cells as well as the regulation by MXenes of nerve cell regeneration in two-dimensional and three-dimensional environments in vitro.MXenes have great potential in regulating the proliferation,differentiation,and maturation of nerve cells and in promoting regeneration and recovery after nerve injury.In addition,this review also presents the main challenges during optimization processes,such as the preparation of stable MXenes and long-term in vivo biosafety,and further discusses future directions in neural tissue engineering.
基金the financial support from the Sunway University International Research Network Grant Scheme(STR-IRNGSSET-GAMRG-01-2022)the Universiti Kebangsaan Malaysia Grant(GUP-2022-080)。
文摘The increasing focus on electrocatalysis for sustainable hydrogen(H_(2))production has prompted significant interest in MXenes,a class of two-dimensional(2D)materials comprising metal carbides,carbonitrides,and nitrides.These materials exhibit intriguing chemical and physical properties,including excellent electrical conductivity and a large surface area,making them attractive candidates for the hydrogen evolution reaction(HER).This scientific review explores recent advancements in MXene-based electrocatalysts for HER kinetics.It discusses various compositions,functionalities,and explicit design principles while providing a comprehensive overview of synthesis methods,exceptional properties,and electro-catalytic approaches for H_(2) production via electrochemical reactions.Furthermore,challenges and future prospects in designing MXenes-based electrocatalysts with enhanced kinetics are highlighted,emphasizing the potential of incorporating different metals to expand the scope of electrochemical reactions.This review suggests possible efforts for developing advanced MXenes-based electrocatalysts,particularly for efficient H_(2) generation through electrochemical water-splitting reactions..
基金supported by the Hong Kong Research Grants Council(Project Number CityU 11218420)the Deanship of Scientific Research at King Khalid University Saudi Arabia for funding through research groups program under Grant Number R.G.P.2/593/44.
文摘MXene has garnered widespread recognition in the scientific com-munity due to its remarkable properties,including excellent thermal stability,high conductivity,good hydrophilicity and dispersibility,easy processability,tunable surface properties,and admirable flexibility.MXenes have been categorized into different families based on the number of M and X layers in M_(n+1)X_(n),such as M_(2)X,M_(3)X_(2),M_(4)X_(3),and,recently,M_(5)X_(4).Among these families,M_(2)X and M_(3)X_(2),par-ticularly Ti_(3)C_(2),have been greatly explored while limited studies have been given to M_(5)X_(4)MXene synthesis.Meanwhile,studies on the M_(4)X_(3)MXene family have developed recently,hence,demanding a compilation of evaluated studies.Herein,this review provides a systematic overview of the latest advancements in M_(4)X_(3)MXenes,focusing on their properties and applications in energy storage devices.The objective of this review is to provide guidance to researchers on fostering M_(4)X_(3)MXene-based nanomaterials,not only for energy storage devices but also for broader applications.
文摘Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural movements of living organisms,aiming to attain enhanced flexibility,adaptability,and versatility.On the other hand,angle-independent structural color has been achieved through innovative design strategies and engineering approaches.By carefully controlling the size,shape,and arrangement of nanostructures,researchers have been able to create materials exhibiting consistent colors regardless of the viewing angle.One promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical,electrical,and optical properties.The integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting possibilities.Overcoming material compatibility issues,improving color reproducibility,scalability,durability,power supply efficiency,and cost-effectiveness will play vital roles in advancing these technologies.This perspective appraises the development of bioinspired MXene-centered soft actuators with angleindependent structural color in soft robotics.
基金the Spanish Ministerio de Ciencia e Innovación through grants PID2021-126076NB-I00 and TED2021-129506B-C22the unit of excellence María de Maeztu CEX2021-001202-M granted to the IQTCUB+2 种基金the Generalitat de Catalunya 2021SGR00079 grantComputational resources have been provided by the Red Española de Supercomputación(RES)QHS-2023-2-0017 and QHS-2023-3-0012 projectsAlso,F.V.thanks the ICREA Academia Award 2023 Ref.Ac2216561.
文摘Finding appropriate photocatalysts for solar-driven water(H_(2)O)splitting to generate hydrogen(H_(2))fuel is a challenging task,particularly when guided by conventional trial-and-error experimental methods.Here,density functional theory(DFT)is used to explore the MXenes photocatalytic properties,an emerging family of two-dimensional(2D)transition metal carbides and nitrides with chemical formula M_(n+1)X_(n)T_(x),known to be semiconductors when having T_(x)terminations.More than 4,000 MXene structures have been screened,considering different compositional(M,X,T_(x),and n)and structural(stacking and termination position)factors,to find suitable MXenes with a bandgap in the visible region and band edges that align with the water-splitting half-reaction potentials.Results from bandgap analysis show how,in general,MXenes with n=1 and transition metals from group III present the most cases with bandgap and promising sizes,with C-MXenes being superior to N-MXenes.From band alignment calculations of candidate systems with a bandgap larger than 1.23 eV,the minimum required for a water-splitting process,Sc_(2)CT_(2),Y_(2)CT_(2)(T_(x)=Cl,Br,S,and Se)and Y_(2)CI_(2)are highlighted as adequate photocatalysts.
