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
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
TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion insertion.However,how to improve the inherently low ionic and elec...TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion insertion.However,how to improve the inherently low ionic and electrical conductivity of TiO_(2)is the problem that needs to be solved.In this work,a smart strategy is adopted to prepare cobalt-doped TiO_(2)@C(Co^(4+)-TiO_(2)@C)hierarchical nanocomposite derived from Co(II)(OH)n@Ti3C2.Compared with TiO_(2)@C(without cobalt doping),Co^(4+)-TiO_(2)@C shows the highest specific capacity(154.7 mAh·g^(-1)at 0.1 A·g^(-1)after 200 cycles)and extraordinary rate performance in HMLBs.The excellent electrochemical performance of Co4+-TiO_(2)@C is ascribed to the synergistic effect of the hierarchical structure and cobalt-doping.Both experimental results and density functional theory(DFT)calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li+migration barrier.This work provides a new insight to design TiO_(2)-based cathode materials with high-performance in HMLBs.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
The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy.Herein,we pres...The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy.Herein,we present a multistep strategy for the synthesis of a Ti_(3)C_(2) MXene ribbon/NiFePx@graphitic N-doped carbon(NC)heterostructure that enables the formation of three-dimensional(3D)Ti_(3)C_(2) MXene ribbon networks and bimetallic phosphide nanoarrays.With the assistance of HF etching and KOH shearing,the MXene sheets were successfully transformed into 3D MXene networks with interlaced MXene ribbons.Notably,a hydrothermal method,ion exchange route,and phosphorization process were used to anchor NiFeP_(x)@NC nanocubes derived from Ni(OH)_(2)/NiFe-based Prussian blue(NiFe-PB)onto the MXene ribbon network.The resulting MXene ribbon/NiFeP_(x)@NC heterostructure demonstrated enhanced oxygen evolution reaction(OER)activity,characterized by a low overpotential(164 mV at a current density of 10 mA cm^(-2))and a low Tafel slope(45 mV dec^(-1)).At the same time,the MXene ribbons/NiFeP_(x)@NC heterostructure exhibited outstanding long-term stability,with a 12 mV potential decay after 5000 cyclic voltammetry(CV)cycles.This study provides a robust pathway for the design of efficient MXene-based heterostructured electrocatalysts for water splitting.展开更多
To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fab...To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fabricated.The material characteristics of ND,Ti_(3)C_(2)MXene,and ND/Ti_(3)C_(2)MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)spectroscopy.The experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti_(3)C_(2) MXene nanosheet prevented the self-stacking of Ti_(3)C_(2)MXene and enhanced the sensitivity of Ti_(3)C_(2) MXene-based QCM humidity sensor.Moreover,the high mechanical modulus of Ti_(3)C_(2) MXene material helped ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor to achieve a high quality factor(>20,000).ND/Ti_(3)C_(2)MXene compositecoated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/%RH,a humidity hysteresis of 1.1%RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3%RH to 97.3%RH.The response mechanism of ND/Ti_(3)C_(2) MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-exponential kinetic adsorption model.Finally,the potential application of ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.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
As a highly toxic heavy metal,Cr(VI)reduction by developing high-efficiency photocatalysts is of great significance.Herein,we firstly design few-layer Ti_(3)C_(2) MXene(FTM)by the hand-operated shaking,show-ing dual a...As a highly toxic heavy metal,Cr(VI)reduction by developing high-efficiency photocatalysts is of great significance.Herein,we firstly design few-layer Ti_(3)C_(2) MXene(FTM)by the hand-operated shaking,show-ing dual advantages of structural stability and more exposed reactive sites.Then,a refluxed process is performed to fabricate FTM/CaIn_(2)S_(4)(FTC) composites,where 2D CaIn_(2)S_(4)(CIS) nanoplates are closely con-nected with 2D FTM to form Schottky junction.The optimal 1-FTC with the FTM/CIS mass ratio of 1 wt.%exhibits the highest activity toward photocatalytic Cr(VI)reduction under visible light.It is well eluci-dated that the broadened light absorption range and promoted charge carrier separation rate induced by the introduction of FTM are responsible for improving photocatalytic activity of CIS.During Cr(VI)photoreduction,1-FTC possesses excellent photo-stability and reusability.The effects of catalyst mass,co-existing ions,water sources and pH values on the Cr(VI)photoreduction efficiency are investigated.Pho-togenerated•O_(2)^(−)and e−are the main radical species accounting for Cr(VI)photoreduction over 1-FTC.The photocatalytic mechanism along with Cr(VI)removal pathway is exploited.This work may provide some insights into constructing FTM-based Schottky junctions for the efficient water purification.展开更多
Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor ...Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor light absorption,insufficient charge separation,and slow reaction kinetics of the photocatalysts.In this study,we designed and synthesized a novel S-scheme heterojunction comprising Ti_(3)C_(2)MXene,CdS nanorods,and nitrogen-doped carbon coated Cu_(2)O(Cu_(2)O@NC)core-shell nanoparticles.Ti_(3)C_(2)MXene as a cocatalyst enhances the light absorption and charge transfer of CdS nanorods.Simultaneously,the core-shell Cu_(2)O@NC nanoparticles establish a pathway for transferring photogenerated electrons and create a favorable band alignment for efficient hydrogen evolution.The synergistic effects of Ti_(3)C_(2)MXene and Cu_(2)O@NC on CdS nanorods result in multiple charge transfer channels and improved photocatalytic performance.The optimal hydrogen evolution rate of the Ti_(3)C_(2)-CdS-Cu_(2)O@NC S-scheme heterojunction photocatalyst is 7.4 times higher than that of pure CdS.Experimental techniques and DFT calculations were employed to explore the structure,morphology,optical properties,charge dynamics,and band structure of the heterojunction.The results revealed that the S-scheme mechanism effectively suppresses the recombination of photogenerated carriers and facilitates the separation and migration of photo-generated electrons and holes to the reaction sites.Furthermore,Ti_(3)C_(2)MXene provides abundant active sites essential for accelerating the surface H_(2)-evolution reaction kinetics.The Cu_(2)O@NC core-shell nanoparticles with a large surface area and high stability are closely adhered to CdS nanorods and establish an S-scheme internal electric field with CdS nanorods to drive charge separation.This investigation provides valuable insights into the rational design of CdS-based photocatalysts,enabling efficient hydrogen production by harnessing the robust kinetic driving force provided by the S-展开更多
While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer meta...While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer metallic conductivity,but their capacitance is limited in aqueous electrolytes.Insertion of partially solvated cations into Ti_(3)C_(2)MXene from lithium-based water-in-salt(WIS)electrolytes enables charge storage at positive potentials,allowing a wider potential window and higher capacitance.Herein,we demonstrate that α-MoO_(3)/Ti_(3)C_(2)hybrids combine the high capacity of α-MoO_(3)and conductivity of Ti_(3)C_(2)in WIS(19.8 m LiCI)electrolyte in a wide1.8 V voltage window.Cyclic voltammograms reveal multiple redox peaks from α-MoO_(3)in addition to the well-separated peaks of Ti_(3)C_(2)in the hybrid electrode.This leads to a higher specific charge and a higher rate capability compared to a carbon and binder containing α-MoO_(3)electrode.These results demonstrate that the addition of MXene to less conductive oxides eliminates the need for conductive carbon additives and binders,leads to a larger amount of charge stored,and increases redox capacity at higher rates.In addition,MXene encapsulated α-MoO_(3)showed improved electrochemical stability,which was attributed to the suppressed dissolution of α-MoO_(3).The work suggests that oxide/MXene hybrids are promising for energy storage.展开更多
Ti_(3)C_(2)MXene is an auspicious energy storage material due to its metallic conductivity and layered assembly.However,in the real working condition of electrochemical energy storage with long cycle charging-discharg...Ti_(3)C_(2)MXene is an auspicious energy storage material due to its metallic conductivity and layered assembly.However,in the real working condition of electrochemical energy storage with long cycle charging-discharging,a structural collapse is usually caused by the stacking of its layers creating a large attenuation of specific capacitance.Inspired by the superlattice effect of magic angle graphene,we conducted microscopical regulation of rotation mismatch on the Ti_(3)C_(2)lattice;consequently,a hexagonal fewlayered Ti_(3)C_(2)free-standing film constructed with Moiré-superlattices.Such finding not only solves the problem of Ti_(3)C_(2)structural collapse but also dramatically improves the specific capacitance of Ti_(3)C_(2)as a supercapacitor electrode under long cycle charging and discharging.The ultra-stable energy storage of this electrode material in a neutral aqueous electrolyte was realized.Moreover,the formation mechanism of rotating Moirépattern is revealed through microscopy and microanalysis of the produced Moirépattern,assisted with modeling and analyzing the underlying mechanism between the Moirépattern and the rotation angle.Our work provides experimental and theoretical support for future construction of Moiré-superlattice structure for a wide range of MXene phases and is undoubtedly promoting the development of MXene materials in the field of energy storage.展开更多
A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape whic...A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and Ti_(3)C_(2) MXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(>99%)of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP)over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO_(2),H_(2)O and F^(-).展开更多
The exploration of advanced MoS_(2)-based electrode materials overcoming their inherent low conductivity and large volume changes is of importance for next-generation energy storage.In this work,we report a simple and...The exploration of advanced MoS_(2)-based electrode materials overcoming their inherent low conductivity and large volume changes is of importance for next-generation energy storage.In this work,we report a simple and high-efficient one-pot hydrothermal approach to prepare a unique and stable 1D/2D heterostructure.In the architecture,ultrathin carbon layer-coated MoS_(2) nanosheets with large expanded interlayer of 1.02 nm are vertically grown onto the Ti_(3)C_(2) MXene and cross-linked carbon nanotubes(CNTs),giving rise to a highly conductive 3D network.The interlayer expanded MoS_(2) nanosheets can greatly facilitate the Na ions/electrons transmission.Meanwhile,the N-doped 1D/2D CNTs-Ti_(3)C_(2) matrix can be used as a strong mechanical support to well relieve the large volume expansion upon cycles.As a combination result of several advantages,the developed quaternary C-MoS_(2)/CNTs-Ti_(3)C_(2) composite anode shows an excellent sodium storage performance(562 mA h g^(-1) at 100 mA g^(-1) after 200 cycles)and rate capability(475 mA h g^(-1) at 2000 mA g^(-1)).The density functional theory calculations further prove that the full combination of layer-expanded MoS_(2) nanosheets and N-doped Ti_(3)C_(2) matrix can significantly enhance the adsorption energy of Na ions,further resulting in the enhancement of sodium storage capabilities.展开更多
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supported by the National Natural Science Foundation of China(No.22278347)the Graduate Research Innovation Project of Xinjiang(No.XJGRI2017002)the Doctoral Innovation Program of Xinjiang University(No.XJUBSCX-2017012).
文摘TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion insertion.However,how to improve the inherently low ionic and electrical conductivity of TiO_(2)is the problem that needs to be solved.In this work,a smart strategy is adopted to prepare cobalt-doped TiO_(2)@C(Co^(4+)-TiO_(2)@C)hierarchical nanocomposite derived from Co(II)(OH)n@Ti3C2.Compared with TiO_(2)@C(without cobalt doping),Co^(4+)-TiO_(2)@C shows the highest specific capacity(154.7 mAh·g^(-1)at 0.1 A·g^(-1)after 200 cycles)and extraordinary rate performance in HMLBs.The excellent electrochemical performance of Co4+-TiO_(2)@C is ascribed to the synergistic effect of the hierarchical structure and cobalt-doping.Both experimental results and density functional theory(DFT)calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li+migration barrier.This work provides a new insight to design TiO_(2)-based cathode materials with high-performance in HMLBs.
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supported by the National Natural Science Foun-dation of China(No.22269010)the Jiangxi Provincial Natural Science Foundation(No.20224BAB214021)+1 种基金the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(No.20212BCJ23020)the Science and Technology Project of the Jiangxi Provincial Department of Education(No.GJJ211305).
文摘The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy.Herein,we present a multistep strategy for the synthesis of a Ti_(3)C_(2) MXene ribbon/NiFePx@graphitic N-doped carbon(NC)heterostructure that enables the formation of three-dimensional(3D)Ti_(3)C_(2) MXene ribbon networks and bimetallic phosphide nanoarrays.With the assistance of HF etching and KOH shearing,the MXene sheets were successfully transformed into 3D MXene networks with interlaced MXene ribbons.Notably,a hydrothermal method,ion exchange route,and phosphorization process were used to anchor NiFeP_(x)@NC nanocubes derived from Ni(OH)_(2)/NiFe-based Prussian blue(NiFe-PB)onto the MXene ribbon network.The resulting MXene ribbon/NiFeP_(x)@NC heterostructure demonstrated enhanced oxygen evolution reaction(OER)activity,characterized by a low overpotential(164 mV at a current density of 10 mA cm^(-2))and a low Tafel slope(45 mV dec^(-1)).At the same time,the MXene ribbons/NiFeP_(x)@NC heterostructure exhibited outstanding long-term stability,with a 12 mV potential decay after 5000 cyclic voltammetry(CV)cycles.This study provides a robust pathway for the design of efficient MXene-based heterostructured electrocatalysts for water splitting.
基金financially supported by the Project funded by the National Natural Science Foundation of China(No.61401047)the China Postdoctoral Science Foundation(No.2018M633349)+1 种基金the Oversea Students Funding Project of the Department of Human Resources and Social Security of Sichuanthe Scientific Research Foundation of CUIT(No.KYQN202210)。
文摘To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was fabricated.The material characteristics of ND,Ti_(3)C_(2)MXene,and ND/Ti_(3)C_(2)MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)spectroscopy.The experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti_(3)C_(2) MXene nanosheet prevented the self-stacking of Ti_(3)C_(2)MXene and enhanced the sensitivity of Ti_(3)C_(2) MXene-based QCM humidity sensor.Moreover,the high mechanical modulus of Ti_(3)C_(2) MXene material helped ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor to achieve a high quality factor(>20,000).ND/Ti_(3)C_(2)MXene compositecoated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/%RH,a humidity hysteresis of 1.1%RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3%RH to 97.3%RH.The response mechanism of ND/Ti_(3)C_(2) MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-exponential kinetic adsorption model.Finally,the potential application of ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.
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This work was financially supported by the National Natural Science Foundation of China(Nos.51902282 and 12274361)the Qinglan Project of Jiangsu of China,the Natural Science Founda-tion of Jiangsu Province(No.BK20211361)the College Natural Science Research Project of Jiangsu Province(No.20KJA430004).
文摘As a highly toxic heavy metal,Cr(VI)reduction by developing high-efficiency photocatalysts is of great significance.Herein,we firstly design few-layer Ti_(3)C_(2) MXene(FTM)by the hand-operated shaking,show-ing dual advantages of structural stability and more exposed reactive sites.Then,a refluxed process is performed to fabricate FTM/CaIn_(2)S_(4)(FTC) composites,where 2D CaIn_(2)S_(4)(CIS) nanoplates are closely con-nected with 2D FTM to form Schottky junction.The optimal 1-FTC with the FTM/CIS mass ratio of 1 wt.%exhibits the highest activity toward photocatalytic Cr(VI)reduction under visible light.It is well eluci-dated that the broadened light absorption range and promoted charge carrier separation rate induced by the introduction of FTM are responsible for improving photocatalytic activity of CIS.During Cr(VI)photoreduction,1-FTC possesses excellent photo-stability and reusability.The effects of catalyst mass,co-existing ions,water sources and pH values on the Cr(VI)photoreduction efficiency are investigated.Pho-togenerated•O_(2)^(−)and e−are the main radical species accounting for Cr(VI)photoreduction over 1-FTC.The photocatalytic mechanism along with Cr(VI)removal pathway is exploited.This work may provide some insights into constructing FTM-based Schottky junctions for the efficient water purification.
基金National Natural Science Foundation of China(21975084,51672089)Natural Science Foundation of Guangdong Province(2021A1515010075)for their support
文摘Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor light absorption,insufficient charge separation,and slow reaction kinetics of the photocatalysts.In this study,we designed and synthesized a novel S-scheme heterojunction comprising Ti_(3)C_(2)MXene,CdS nanorods,and nitrogen-doped carbon coated Cu_(2)O(Cu_(2)O@NC)core-shell nanoparticles.Ti_(3)C_(2)MXene as a cocatalyst enhances the light absorption and charge transfer of CdS nanorods.Simultaneously,the core-shell Cu_(2)O@NC nanoparticles establish a pathway for transferring photogenerated electrons and create a favorable band alignment for efficient hydrogen evolution.The synergistic effects of Ti_(3)C_(2)MXene and Cu_(2)O@NC on CdS nanorods result in multiple charge transfer channels and improved photocatalytic performance.The optimal hydrogen evolution rate of the Ti_(3)C_(2)-CdS-Cu_(2)O@NC S-scheme heterojunction photocatalyst is 7.4 times higher than that of pure CdS.Experimental techniques and DFT calculations were employed to explore the structure,morphology,optical properties,charge dynamics,and band structure of the heterojunction.The results revealed that the S-scheme mechanism effectively suppresses the recombination of photogenerated carriers and facilitates the separation and migration of photo-generated electrons and holes to the reaction sites.Furthermore,Ti_(3)C_(2)MXene provides abundant active sites essential for accelerating the surface H_(2)-evolution reaction kinetics.The Cu_(2)O@NC core-shell nanoparticles with a large surface area and high stability are closely adhered to CdS nanorods and establish an S-scheme internal electric field with CdS nanorods to drive charge separation.This investigation provides valuable insights into the rational design of CdS-based photocatalysts,enabling efficient hydrogen production by harnessing the robust kinetic driving force provided by the S-
基金supported by the Fluid Interface Reacions and Transport(FIRST)Centeran Energy Frontier Research Center supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences+1 种基金Synthesis,XRD,and SEM characterization of α-MoO_(3) were supported as a part of the Center for Mesoscale Transport PropertiesEnergy Frontier Research Center supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,under award#DE-SC0012673
文摘While transition-metal oxides such as α-MoO_(3)provide high capacity,their use is limited by modest electronic conductivity and electrochemical instability in aqueous electrolytes.Two-dimensional(2D)MXenes,offer metallic conductivity,but their capacitance is limited in aqueous electrolytes.Insertion of partially solvated cations into Ti_(3)C_(2)MXene from lithium-based water-in-salt(WIS)electrolytes enables charge storage at positive potentials,allowing a wider potential window and higher capacitance.Herein,we demonstrate that α-MoO_(3)/Ti_(3)C_(2)hybrids combine the high capacity of α-MoO_(3)and conductivity of Ti_(3)C_(2)in WIS(19.8 m LiCI)electrolyte in a wide1.8 V voltage window.Cyclic voltammograms reveal multiple redox peaks from α-MoO_(3)in addition to the well-separated peaks of Ti_(3)C_(2)in the hybrid electrode.This leads to a higher specific charge and a higher rate capability compared to a carbon and binder containing α-MoO_(3)electrode.These results demonstrate that the addition of MXene to less conductive oxides eliminates the need for conductive carbon additives and binders,leads to a larger amount of charge stored,and increases redox capacity at higher rates.In addition,MXene encapsulated α-MoO_(3)showed improved electrochemical stability,which was attributed to the suppressed dissolution of α-MoO_(3).The work suggests that oxide/MXene hybrids are promising for energy storage.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.51971106 and 52272209)Basic Scientific Research Project of Higher Education Department of Liaoning Province(No.LJKMZ20220961)the Program for Liaoning Distinguished Professor.
文摘Ti_(3)C_(2)MXene is an auspicious energy storage material due to its metallic conductivity and layered assembly.However,in the real working condition of electrochemical energy storage with long cycle charging-discharging,a structural collapse is usually caused by the stacking of its layers creating a large attenuation of specific capacitance.Inspired by the superlattice effect of magic angle graphene,we conducted microscopical regulation of rotation mismatch on the Ti_(3)C_(2)lattice;consequently,a hexagonal fewlayered Ti_(3)C_(2)free-standing film constructed with Moiré-superlattices.Such finding not only solves the problem of Ti_(3)C_(2)structural collapse but also dramatically improves the specific capacitance of Ti_(3)C_(2)as a supercapacitor electrode under long cycle charging and discharging.The ultra-stable energy storage of this electrode material in a neutral aqueous electrolyte was realized.Moreover,the formation mechanism of rotating Moirépattern is revealed through microscopy and microanalysis of the produced Moirépattern,assisted with modeling and analyzing the underlying mechanism between the Moirépattern and the rotation angle.Our work provides experimental and theoretical support for future construction of Moiré-superlattice structure for a wide range of MXene phases and is undoubtedly promoting the development of MXene materials in the field of energy storage.
基金financially supported by the National Natural Science Foundation of China(No.51878169)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110760)+1 种基金Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)。
文摘A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and Ti_(3)C_(2) MXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(>99%)of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP)over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO_(2),H_(2)O and F^(-).
基金supported by the Shuguang Program from Shanghai Education Development Foundation and Shanghai Municipal Education Commission(18SG035)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(KF2015)。
文摘The exploration of advanced MoS_(2)-based electrode materials overcoming their inherent low conductivity and large volume changes is of importance for next-generation energy storage.In this work,we report a simple and high-efficient one-pot hydrothermal approach to prepare a unique and stable 1D/2D heterostructure.In the architecture,ultrathin carbon layer-coated MoS_(2) nanosheets with large expanded interlayer of 1.02 nm are vertically grown onto the Ti_(3)C_(2) MXene and cross-linked carbon nanotubes(CNTs),giving rise to a highly conductive 3D network.The interlayer expanded MoS_(2) nanosheets can greatly facilitate the Na ions/electrons transmission.Meanwhile,the N-doped 1D/2D CNTs-Ti_(3)C_(2) matrix can be used as a strong mechanical support to well relieve the large volume expansion upon cycles.As a combination result of several advantages,the developed quaternary C-MoS_(2)/CNTs-Ti_(3)C_(2) composite anode shows an excellent sodium storage performance(562 mA h g^(-1) at 100 mA g^(-1) after 200 cycles)and rate capability(475 mA h g^(-1) at 2000 mA g^(-1)).The density functional theory calculations further prove that the full combination of layer-expanded MoS_(2) nanosheets and N-doped Ti_(3)C_(2) matrix can significantly enhance the adsorption energy of Na ions,further resulting in the enhancement of sodium storage capabilities.
