水资源匮乏是现代化发展中面临的全球性问题,太阳能界面水汽转换(Interfacial Solar Steam Generation,ISSG)是一种高效、绿色、低成本进行海水淡化和废水处理的方法。ISSG使用绿色的太阳能作为热源,通过光热转换并将热限制在水气界面...水资源匮乏是现代化发展中面临的全球性问题,太阳能界面水汽转换(Interfacial Solar Steam Generation,ISSG)是一种高效、绿色、低成本进行海水淡化和废水处理的方法。ISSG使用绿色的太阳能作为热源,通过光热转换并将热限制在水气界面上以高效产生蒸气,然后经过冷凝收集获得清洁水。设计和构筑具有强光吸收的光热转换材料是ISSG的技术核心。Ti_(3)C_(2)-MXene是一种新型二维碳化钛材料,具有比表面积大、水分散性好和光热转换效率高等优点,在ISSG领域具有巨大的应用潜力。本文介绍了ISSG技术和MXene,总结了光热转换材料的设计原则,论述了Ti_(3)C_(2)-MXene复合材料在ISSG领域的研究进展,其中包括二维MXene薄膜、三维MXene气凝胶和水凝胶、生物基-MXene复合材料的构筑和性能等,并分析了Ti_(3)C_(2)-MXene所面临的挑战和发展前景。展开更多
High-performance flexible pressure sensors provide comprehensive tactile perception and are applied in human activity monitoring,soft robotics,medical treatment,and human-computer interface.However,these flexible pres...High-performance flexible pressure sensors provide comprehensive tactile perception and are applied in human activity monitoring,soft robotics,medical treatment,and human-computer interface.However,these flexible pressure sensors require extensive nano-architectural design and complicated manufacturing and are timeconsuming.Herein,a highly sensitive,flexible piezoresistive tactile sensor is designed and fabricated,consisting of three main parts:the randomly distributed microstructure on T-ZnOw/PDMS film as a top substrate,multilayer Ti_(3)C_(2)-MXene film as an intermediate conductive filler,and the few-layer Ti_(3)C_(2)-MXene nanosheetbased interdigital electrodes as the bottom substrate.The MXene-based piezoresistive sensor with randomly distributed microstructure exhibits a high sensitivity over a broad pressure range(less than 10 kPa for 175 kPa^(-1))and possesses an out-standing permanence of up to 5000 cycles.Moreover,a 16-pixel sensor array is designed,and its potential applications in visualizing pressure distribution and an example of tactile feedback are demonstrated.This fully sprayed MXene-based pressure sensor,with high sensitivity and excellent durability,can be widely used in,electronic skin,intelligent robots,and many other emerging technologies.展开更多
The rapid recombination of photo-generated electron-hole pairs,insufficient active sites,and strong photocorrosion have considerably restricted the practical application of Cd S in photocatalytic fields.Herein,we desi...The rapid recombination of photo-generated electron-hole pairs,insufficient active sites,and strong photocorrosion have considerably restricted the practical application of Cd S in photocatalytic fields.Herein,we designed and constructed a 2D/2D/2D layered heterojunction photocatalyst with cascaded 2D coupling interfaces.Experiments using electron spin resonance spectroscopy,ultraviolet photoelectron spectroscopy,and in-situ irradiation X-ray photoelectron spectroscopy were conducted to confirm the 2D layered CdS/WO_(3) step-scheme(S-scheme)heterojunctions and CdS/MX ohmic junctions.Impressively,it was found that the strong interfacial electric fields in the S-scheme heterojunction photocatalysts could effectively promote spatially directional charge separation and transport between CdS and WO_(3) nanosheets.In addition,2D Ti_(3)C_(2) MXene nanosheets with a smaller work function and excellent metal conductivity when used as a co-catalyst could build ohmic junctions with Cd S nanosheets,thus providing a greater number of electron transfer pathways and hydrogen evolution sites.Results showed that the highest visible-light hydrogen evolution rate of the optimized MX-Cd S/WO_(3) layered multi-heterostructures could reach as high as 27.5 mmol/g/h,which was 11.0 times higher than that of pure CdS nanosheets.Notably,the apparent quantum efficiency reached 12.0% at 450 nm.It is hoped that this study offers a reliable approach for developing multifunctional photocatalysts by integrating S-scheme and ohmic-junction built-in electric fields and rationally designing a 2D/2D interface for efficient light-to-hydrogen fuel production.展开更多
Photocatalytic degradation and hydrogen production using solar energy through semiconductor photocatalysts are deemed to be a powerful approach for solving environmental and energy crisis.However,the biggest challenge...Photocatalytic degradation and hydrogen production using solar energy through semiconductor photocatalysts are deemed to be a powerful approach for solving environmental and energy crisis.However,the biggest challenge in photocatalysis is the efficient separation of photo-induced carriers.To this end,we report that the mesoporous TiO_(2)nanoparticles are anchored on highly conductive Ti_(3)C_(2)MXene co-catalyst by electrostatic self-assembly strategy.The constructed mesoporous TiO_(2)/Ti_(3)C_(2)composites display that the mesoporous TiO_(2)nanoparticles are uniformly distributed on the surface of layer structured Ti_(3)C_(2)nanosheets.More importantly,the as-obtained mesoporous TiO_(2)/Ti_(3)C_(2)composites reveal the significantly enhanced light absorption performance,photo-induced carriers separation and transfer ability,thus boosting the photocatalytic activity.The photocatalytic methyl orange degradation efficiency of mesoporous TiO_(2)/Ti_(3)C_(2)composite with an optimized Ti_(3)C_(2)content(3 wt%)can reach 99.6%within 40 min.The capture experiments of active species confirm that the·O_(2)-and·OH play major role in photocatalytic degradation process.Furthermore,the optimized mesoporous TiO_(2)/Ti_(3)C_(2)composite also shows an excellent photocatalytic H2 production rate of 218.85μmol g^(-1)h^(-1),resulting in a 5.6 times activity as compared with the pristine mesoporous TiO_(2)nanoparticles.This study demonstrates that the MXene family materials can be applied as highly efficient noble-metal-free co-catalysts in the field of photocatalysis.展开更多
In this rapidly developing society,it is always crucial to exploit new materials with suitable properties to meet specific application demands.Two-dimensional(2 D)transition metal carbon/nitrides(MXenes)are a novel gr...In this rapidly developing society,it is always crucial to exploit new materials with suitable properties to meet specific application demands.Two-dimensional(2 D)transition metal carbon/nitrides(MXenes)are a novel graphene-like material with exciting research potential in recent years.Among them,Ti_(3)C_(2)debuts in a central position due to its relatively longer research history,mature synthetic process,and incredibly rich store of merits,such as good flexibility,large specific surface area,abundant termination groups,excellent electrical conductivity,and light-to-heat conversion ability.In this review,recent research progress on Ti_(3)C_(2)MXene and its composites was updated mainly from three aspects,including their fundamentals,synthesis,and applications.It has been found that diverse applications of Ti3 C2-based composites are inseparable and correlated with each other,which were linked by their unique physicochemical properties.In the end,a summary and a perspective on future opportunities and challenges of Ti_(3)C_(2)were given to offer theoretical and technical guidelines for further investigation on MXene family.展开更多
Establishing highly effective charge transfer channels in carbon nitride(g-C_(3)N_(4)) to enhance its photocatalytic activity is still a challenging issue.Herein,the delaminated 2D Ti_(3)C_(2) MXene nanosheets were em...Establishing highly effective charge transfer channels in carbon nitride(g-C_(3)N_(4)) to enhance its photocatalytic activity is still a challenging issue.Herein,the delaminated 2D Ti_(3)C_(2) MXene nanosheets were employed to decorate the P-doped tubular g-C_(3)N_(4)(PTCN)for engineering 1D/2D Schottky heterojunction(PTCN/TC)through electrostatic self-assembly.The optimized PTCN/TC exhibited the highest hydrogen evolution rate(565 μmol h^(-1)g^(-1)),which was 4.3 and 2.0-fold higher than pristine bulk g-C_(3)N_(4) and PTCN,respectively.Such enhancement may be primarily attributed to the phosphorus heteroatom doped and unique structure of 1D/2D g-C_(3)N_(4)/Ti_(3)C_(2) Schottky heterojunction,enhancing the light-harvesting and charges’separation.One-dimensional pathway of g-C_(3)N_(4) tube and built-in electric field of interfacial Schottky effect can significantly facilitate the spatial separation of photogenerated charge carriers,and simultaneously inhibit their recombination via Schottky barrier.In this composite,metallic Ti_(3)C_(2) was served as electrons sink and photons collector.Moreover,ultrathin Ti_(3)C_(2) flake with exposed terminal metal sites as a co-catalyst exhibited higher photocatalytic reactivity in H2 evolution compared to carbon materials(such as reduced graphene oxide).This work not only proposed the mechanism of tubular g-C_(3)N_(4)/Ti_(3)C_(2) Schottky junction in photocatalysis,but also provided a feasible way to load ultrathin Ti_(3)C_(2) as a co-catalyst for designing highly efficient photocatalysts.展开更多
A PLGA/Ti_(3)C_(2) hybrid coating was successfully deposited on the surface of magnesium-strontium(Mg-Sr)alloys.Compared with the corrosion current density(icorr)of the Mg-Sr alloy(7.13×10^−5 A/cm^2),the modified...A PLGA/Ti_(3)C_(2) hybrid coating was successfully deposited on the surface of magnesium-strontium(Mg-Sr)alloys.Compared with the corrosion current density(icorr)of the Mg-Sr alloy(7.13×10^−5 A/cm^2),the modified samples(Mg/PLGA/Ti_(3)C_(2))was lower by approximately four orders of magnitude(7.65×10^−9 A/cm^2).After near infrared 808 nm laser irradiation,the icorr of the modified samples increased to 3.48×10^−7 A/cm^2.The mechanism is that the local hyperthermia induced the free volume expansion of PLGA,and the increase in intermolecular gap enhanced the penetration of electrolytes.Meanwhile,the cytotoxicity study showed that the hybrid coating endowed the Mg-Sr alloy with enhanced biocompatibility.展开更多
As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods...As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods and research to date,many new features have yet to be uncovered.Here,to explore their new properties and expand biological applications,chlorine and nitrogen co-doped Ti_(3)C_(2)MXene quantum dots(Cl,N-Ti_(3)C_(2)MQDs)were designed and synthesized,and their hydroxyl radical scavenging properties were investigated for the first time,revealing outstanding performance.Cl,N-Ti_(3)C_(2)MQDs was directly stripped from bulk Ti_(3)Al C_(2)by electrochemical etching,while N and Cl are successfully introduced to carbon skeleton and Ti boundaries in the etching process by electrochemical reactions between selected electrolytes and Ti_(3)C_(2)skeleton,respectively.The obtained Cl,N-Ti_(3)C_(2)MQDs exhibit large surface-to-volume ratio due to small particle size(ca.3.45 nm)and excellent higher scavenging activity(93.3%)and lower usage(12.5μg/m L)towards hydroxyl radicals than the previous reported graphene-based nanoparticles.The underlying mechanism of scavenging activity was also studied based on the reduction experiment with potassium permanganate(KMnO_(4)).The reducing ability of the intrinsic Ti_(3)C_(2)structure and electron donation of double dopants are the main contributors to the outstanding scavenging activity.展开更多
文摘水资源匮乏是现代化发展中面临的全球性问题,太阳能界面水汽转换(Interfacial Solar Steam Generation,ISSG)是一种高效、绿色、低成本进行海水淡化和废水处理的方法。ISSG使用绿色的太阳能作为热源,通过光热转换并将热限制在水气界面上以高效产生蒸气,然后经过冷凝收集获得清洁水。设计和构筑具有强光吸收的光热转换材料是ISSG的技术核心。Ti_(3)C_(2)-MXene是一种新型二维碳化钛材料,具有比表面积大、水分散性好和光热转换效率高等优点,在ISSG领域具有巨大的应用潜力。本文介绍了ISSG技术和MXene,总结了光热转换材料的设计原则,论述了Ti_(3)C_(2)-MXene复合材料在ISSG领域的研究进展,其中包括二维MXene薄膜、三维MXene气凝胶和水凝胶、生物基-MXene复合材料的构筑和性能等,并分析了Ti_(3)C_(2)-MXene所面临的挑战和发展前景。
基金supported by the Key Research and Development Program of Shanxi Province(No.202102130501011)the Fund for Shanxi“1331 Project”Key Subject Construction(1331KSC)National Key Research and Development Program of China(Grant No.2019YFB2004800).
文摘High-performance flexible pressure sensors provide comprehensive tactile perception and are applied in human activity monitoring,soft robotics,medical treatment,and human-computer interface.However,these flexible pressure sensors require extensive nano-architectural design and complicated manufacturing and are timeconsuming.Herein,a highly sensitive,flexible piezoresistive tactile sensor is designed and fabricated,consisting of three main parts:the randomly distributed microstructure on T-ZnOw/PDMS film as a top substrate,multilayer Ti_(3)C_(2)-MXene film as an intermediate conductive filler,and the few-layer Ti_(3)C_(2)-MXene nanosheetbased interdigital electrodes as the bottom substrate.The MXene-based piezoresistive sensor with randomly distributed microstructure exhibits a high sensitivity over a broad pressure range(less than 10 kPa for 175 kPa^(-1))and possesses an out-standing permanence of up to 5000 cycles.Moreover,a 16-pixel sensor array is designed,and its potential applications in visualizing pressure distribution and an example of tactile feedback are demonstrated.This fully sprayed MXene-based pressure sensor,with high sensitivity and excellent durability,can be widely used in,electronic skin,intelligent robots,and many other emerging technologies.
文摘The rapid recombination of photo-generated electron-hole pairs,insufficient active sites,and strong photocorrosion have considerably restricted the practical application of Cd S in photocatalytic fields.Herein,we designed and constructed a 2D/2D/2D layered heterojunction photocatalyst with cascaded 2D coupling interfaces.Experiments using electron spin resonance spectroscopy,ultraviolet photoelectron spectroscopy,and in-situ irradiation X-ray photoelectron spectroscopy were conducted to confirm the 2D layered CdS/WO_(3) step-scheme(S-scheme)heterojunctions and CdS/MX ohmic junctions.Impressively,it was found that the strong interfacial electric fields in the S-scheme heterojunction photocatalysts could effectively promote spatially directional charge separation and transport between CdS and WO_(3) nanosheets.In addition,2D Ti_(3)C_(2) MXene nanosheets with a smaller work function and excellent metal conductivity when used as a co-catalyst could build ohmic junctions with Cd S nanosheets,thus providing a greater number of electron transfer pathways and hydrogen evolution sites.Results showed that the highest visible-light hydrogen evolution rate of the optimized MX-Cd S/WO_(3) layered multi-heterostructures could reach as high as 27.5 mmol/g/h,which was 11.0 times higher than that of pure CdS nanosheets.Notably,the apparent quantum efficiency reached 12.0% at 450 nm.It is hoped that this study offers a reliable approach for developing multifunctional photocatalysts by integrating S-scheme and ohmic-junction built-in electric fields and rationally designing a 2D/2D interface for efficient light-to-hydrogen fuel production.
文摘Photocatalytic degradation and hydrogen production using solar energy through semiconductor photocatalysts are deemed to be a powerful approach for solving environmental and energy crisis.However,the biggest challenge in photocatalysis is the efficient separation of photo-induced carriers.To this end,we report that the mesoporous TiO_(2)nanoparticles are anchored on highly conductive Ti_(3)C_(2)MXene co-catalyst by electrostatic self-assembly strategy.The constructed mesoporous TiO_(2)/Ti_(3)C_(2)composites display that the mesoporous TiO_(2)nanoparticles are uniformly distributed on the surface of layer structured Ti_(3)C_(2)nanosheets.More importantly,the as-obtained mesoporous TiO_(2)/Ti_(3)C_(2)composites reveal the significantly enhanced light absorption performance,photo-induced carriers separation and transfer ability,thus boosting the photocatalytic activity.The photocatalytic methyl orange degradation efficiency of mesoporous TiO_(2)/Ti_(3)C_(2)composite with an optimized Ti_(3)C_(2)content(3 wt%)can reach 99.6%within 40 min.The capture experiments of active species confirm that the·O_(2)-and·OH play major role in photocatalytic degradation process.Furthermore,the optimized mesoporous TiO_(2)/Ti_(3)C_(2)composite also shows an excellent photocatalytic H2 production rate of 218.85μmol g^(-1)h^(-1),resulting in a 5.6 times activity as compared with the pristine mesoporous TiO_(2)nanoparticles.This study demonstrates that the MXene family materials can be applied as highly efficient noble-metal-free co-catalysts in the field of photocatalysis.
基金financially supported by the National Natural Science Foundation of China(No.21972171)Hubei Provincial Natural Science Foundation,China(No.2021CFA022)。
文摘In this rapidly developing society,it is always crucial to exploit new materials with suitable properties to meet specific application demands.Two-dimensional(2 D)transition metal carbon/nitrides(MXenes)are a novel graphene-like material with exciting research potential in recent years.Among them,Ti_(3)C_(2)debuts in a central position due to its relatively longer research history,mature synthetic process,and incredibly rich store of merits,such as good flexibility,large specific surface area,abundant termination groups,excellent electrical conductivity,and light-to-heat conversion ability.In this review,recent research progress on Ti_(3)C_(2)MXene and its composites was updated mainly from three aspects,including their fundamentals,synthesis,and applications.It has been found that diverse applications of Ti3 C2-based composites are inseparable and correlated with each other,which were linked by their unique physicochemical properties.In the end,a summary and a perspective on future opportunities and challenges of Ti_(3)C_(2)were given to offer theoretical and technical guidelines for further investigation on MXene family.
基金the financial supports from the National Natural Science Foundation of China(No.:22002146)Taishan Scholars Foundation of Shandong province(No.:tsqn201909058).
文摘Establishing highly effective charge transfer channels in carbon nitride(g-C_(3)N_(4)) to enhance its photocatalytic activity is still a challenging issue.Herein,the delaminated 2D Ti_(3)C_(2) MXene nanosheets were employed to decorate the P-doped tubular g-C_(3)N_(4)(PTCN)for engineering 1D/2D Schottky heterojunction(PTCN/TC)through electrostatic self-assembly.The optimized PTCN/TC exhibited the highest hydrogen evolution rate(565 μmol h^(-1)g^(-1)),which was 4.3 and 2.0-fold higher than pristine bulk g-C_(3)N_(4) and PTCN,respectively.Such enhancement may be primarily attributed to the phosphorus heteroatom doped and unique structure of 1D/2D g-C_(3)N_(4)/Ti_(3)C_(2) Schottky heterojunction,enhancing the light-harvesting and charges’separation.One-dimensional pathway of g-C_(3)N_(4) tube and built-in electric field of interfacial Schottky effect can significantly facilitate the spatial separation of photogenerated charge carriers,and simultaneously inhibit their recombination via Schottky barrier.In this composite,metallic Ti_(3)C_(2) was served as electrons sink and photons collector.Moreover,ultrathin Ti_(3)C_(2) flake with exposed terminal metal sites as a co-catalyst exhibited higher photocatalytic reactivity in H2 evolution compared to carbon materials(such as reduced graphene oxide).This work not only proposed the mechanism of tubular g-C_(3)N_(4)/Ti_(3)C_(2) Schottky junction in photocatalysis,but also provided a feasible way to load ultrathin Ti_(3)C_(2) as a co-catalyst for designing highly efficient photocatalysts.
基金This study was jointly supported by the Natural Science Fund of Hubei Province no.2018CFA064,the National Science Fund for Distinguished Young Scholars no.51925104the National Natural Science Foundation of China grant nos.51671081 and 51871162+1 种基金Hong Kong ITC(ITS/287/17,GHX/002/14SZ)Health and Medical Research Fund(No.03142446).
文摘A PLGA/Ti_(3)C_(2) hybrid coating was successfully deposited on the surface of magnesium-strontium(Mg-Sr)alloys.Compared with the corrosion current density(icorr)of the Mg-Sr alloy(7.13×10^−5 A/cm^2),the modified samples(Mg/PLGA/Ti_(3)C_(2))was lower by approximately four orders of magnitude(7.65×10^−9 A/cm^2).After near infrared 808 nm laser irradiation,the icorr of the modified samples increased to 3.48×10^−7 A/cm^2.The mechanism is that the local hyperthermia induced the free volume expansion of PLGA,and the increase in intermolecular gap enhanced the penetration of electrolytes.Meanwhile,the cytotoxicity study showed that the hybrid coating endowed the Mg-Sr alloy with enhanced biocompatibility.
基金National Natural Science Foundation of China(Grant No.21674011,21404008)Beijing Municipal Natural Science Foundation(Grant No.2172040)+1 种基金Beijing Organization department outstanding talented person project(2013D009006000001)the Fundamental Research Funds for the Central Universities(FRF-GF-17-B11)。
文摘As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods and research to date,many new features have yet to be uncovered.Here,to explore their new properties and expand biological applications,chlorine and nitrogen co-doped Ti_(3)C_(2)MXene quantum dots(Cl,N-Ti_(3)C_(2)MQDs)were designed and synthesized,and their hydroxyl radical scavenging properties were investigated for the first time,revealing outstanding performance.Cl,N-Ti_(3)C_(2)MQDs was directly stripped from bulk Ti_(3)Al C_(2)by electrochemical etching,while N and Cl are successfully introduced to carbon skeleton and Ti boundaries in the etching process by electrochemical reactions between selected electrolytes and Ti_(3)C_(2)skeleton,respectively.The obtained Cl,N-Ti_(3)C_(2)MQDs exhibit large surface-to-volume ratio due to small particle size(ca.3.45 nm)and excellent higher scavenging activity(93.3%)and lower usage(12.5μg/m L)towards hydroxyl radicals than the previous reported graphene-based nanoparticles.The underlying mechanism of scavenging activity was also studied based on the reduction experiment with potassium permanganate(KMnO_(4)).The reducing ability of the intrinsic Ti_(3)C_(2)structure and electron donation of double dopants are the main contributors to the outstanding scavenging activity.
