As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires com...As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.展开更多
Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the ma...Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.展开更多
The application of photocatalytic technology in treating various environmental pollution issues has been extensively studied.However,its further utilization has been hindered by the limited response to visible light a...The application of photocatalytic technology in treating various environmental pollution issues has been extensively studied.However,its further utilization has been hindered by the limited response to visible light and the serious recombination of charge carriers.In this study,the two-dimensional(2D)layered carbon-supported TiO_(2)particles derived from Ti_(3)C_(2)Mxene were tightly attached on Bi_(2)WO_(6)containing oxygen-rich vacancies,fabricating an efficient S-scheme bifunctional heterojunction.This development aimed to improve the photocatalytic performance towards antibiotics degradation and NO removal.The photochemical characterizations confirmed that the presence of oxygen vacancies broaden the visible light responsiveness of Bi_(2)WO_(6).Subsequently,the formation of S-scheme heterojunction between oxygen vacancy-containing Bi_(2)WO_(6)and TiO_(2)allowed for the maximum retention of the high oxidation and reduction capabilities of the monomer material.Simultaneously,layered carbon between Bi_(2)WO_(6)and TiO_(2)accelerated charge transfer and carrier separation.The optimized BWO/TiO_(2)@C exhibited superior performance,with an 84.03%degradation rate of tetracycline(TC)and a 44.2%removal rate of NO under visible light,representing 1.54 and 4.79 times the performance of the original Bi_(2)WO_(6),respectively.Intermediate species generated during the photocatalytic oxidation processes of TC and NO were identified using liquid chromatograph mass spectrometry(LC-MS)and in-situ DRIFTS.By combining electron paramagnetic resonance(EPR)and density functional theory(DFT)calculations,in-depth mechanisms were elucidated.This study sheds new light on the applications of Bi_(2)WO_(6)and MXene in photocatalysis,offering potential for the development of efficient dual-functional photocatalysts for addressing water and air pollution.展开更多
Developing an efficient electrocatalyst for superior electrochemical water splitting(EWS)is crucial for achieving comprehensive hydrogen production.A heterostructured electrocatalyst,free of noble metals,Ti_(3)C_(2)MX...Developing an efficient electrocatalyst for superior electrochemical water splitting(EWS)is crucial for achieving comprehensive hydrogen production.A heterostructured electrocatalyst,free of noble metals,Ti_(3)C_(2)MXene nanosheet-integrated cobalt-doped nickel hydroxide(NHCoMX)composite was synthesized via a hydrothermal method.The abundant pores in the Ti_(3)C_(2)MXene nanosheet(MX)-integrated microarchitecture increased the number of active sites and facilitated charge transfer,thus enhancing electrocatalysis.Specifically,the MXenhanced charge transfer considerably transformed the microelectronic structure of cobalt-doped Ni(OH)2(NHCo),which promoted its hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Hence,as an EWS catalyst,NHCoMX exhibited an exceptional electrocatalytic activity,demonstrating OER and HER overpotentials of 310 mV and 73 mV,respectively,with low Tafel slopes of 65 mV dec^(-1)and 85 mV dec^(-1),respectively;it exhibited a current density of 10 mV cm^(-2)in 1.0 mol L^(-1)KOH,representing the closest efficiency to the noble state-of-the-art RuO2 and Pt/C catalyst.Furthermore,the developed electrocatalyst improved the activities of both HER and OER,leading to an overall EWS current density of 10 mA cm^(-2)at 1.72 V in an alkaline electrolyte with two electrodes.This study describes an efficient heterostructured NHCoMX composite electrocatalyst.It is significantly comparable to the noble state-of-the-art electrocatalysts and can be extended to fabricate resourceful catalysts for large-scale EWS applications.展开更多
3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,ex...3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,excellent pseudocapacitance,and fast charging capabilities.However,searching for eco-friendly aqueous Ti_(3)C_(2)T_(x) MXene-based inks without additives and preventing severe restack of MXene nanosheets in high-concentration inks are significantly challenging.This study develops an additive-free,highly printable,viscosity adjustable,and environmentally friendly MXene/carbon nanotube(CNT)hybrid aqueous inks,in which the CNT can not only adjust the viscosity of Ti_(3)C_(2)T_(x) MXene inks but also widen the interlayer spacing of adjacent Ti_(3)C_(2)T_(x) MXene nanosheets effectively.The optimized MXene/CNT composite inks are successfully adopted to construct various configurations of MSCs with remarkable shape fidelity and geometric accuracy,together with enhanced surface area accessibility for electrons and ions diffusion.As a result,the constructed interdigital symmetrical MSCs demonstrate outstanding areal capacitance(1249.3 mF cm^(-2)),superior energy density(111μWh cm^(-2) at 0.4mWcm^(-2)),and high power density(8mWcm^(-2) at 47.1μWh cm^(-2)).Furthermore,a self-powered modular system of solar cells integrated with MXene/CNT-MSCs and pressure sensors is successfully tailored,simultaneously achieving efficient solar energy collection and real-time human activities monitoring.This work offers insight into the understanding of the role of CNTs in MXene/CNT ink.Moreover,it provides a new approach for preparing environmentally friendly MXene-based inks for the 3D printing of high-performance MSCs,contributing to the development of miniaturized,flexible,and self-powered printable electronic microsystems.展开更多
TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bul...TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.展开更多
基金support from the National Key Research and Development Program of China(No.2021YFB3701503)the Key Research and Development Program of Ningbo,China(No.2023Z107).
文摘As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.
基金supported by the National Natural Science Foundation of China(No.21773089)the Henan Center for Outstanding Overseas Scientist(No.GZS2024004).
文摘Herein,a new type of two-dimensional(2D)/2D Ti_(3)C_(2)/TiO_(2) heterojunction was developed for efficient photocatalytic nitrogen reduction reaction(NRR),in which TiO_(2) nanosheets(TiO_(2) Ns)were designed as the main catalyst,while Ti_(3)C_(2) MXene served as the co-catalyst.Experimental and theoretical results revealed that Ti_(3)C_(2) MXene introduced electron-rich unsaturated Ti sites,serving as highly active sites for both the adsorption and activation of N_(2) on the Ti_(3)C_(2)/TiO_(2) heterojunction.Furthermore,the 2D/2D Ti_(3)C_(2)/TiO_(2) heterostructure greatly promoted the directional separation and transfer of charge carriers,facilitated by the internal electric field.This structural feature enabled the spatial separation of the N_(2) reduction and H2 O oxidation half-reactions on the distinct surfaces of Ti_(3)C_(2)(001)and TiO_(2)(001),con-sequently reducing the reaction energy barrier for each respective process.The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photo-catalytic NRR activity.As a result,the optimized Ti_(3)C_(2)/TiO_(2) heterojunction exhibited a high NH_(3) produc-tion rate of 24.4μmol g−1 h−1 in the absence of sacrificial agents,representing a remarkable 12.8-fold increase compared to individual TiO_(2) Ns.This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism under-lying surface active sites in the photocatalytic NRR process.
基金supported by the National Natural Science Foundation of China(Nos.22001026 and 52100179)the Natural Scienceof Chongqing(Nos.CSTB2024NSCQLZX0073 and CSTB2022NSCQ-MSX1308)+1 种基金the Chongqing College Students’Innovation and Entrepreneurship Training Program(No.S202311799025)the Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJZD-K202300806,KJQN202200821,KJQN202400810,and KJQN202100831)。
文摘The application of photocatalytic technology in treating various environmental pollution issues has been extensively studied.However,its further utilization has been hindered by the limited response to visible light and the serious recombination of charge carriers.In this study,the two-dimensional(2D)layered carbon-supported TiO_(2)particles derived from Ti_(3)C_(2)Mxene were tightly attached on Bi_(2)WO_(6)containing oxygen-rich vacancies,fabricating an efficient S-scheme bifunctional heterojunction.This development aimed to improve the photocatalytic performance towards antibiotics degradation and NO removal.The photochemical characterizations confirmed that the presence of oxygen vacancies broaden the visible light responsiveness of Bi_(2)WO_(6).Subsequently,the formation of S-scheme heterojunction between oxygen vacancy-containing Bi_(2)WO_(6)and TiO_(2)allowed for the maximum retention of the high oxidation and reduction capabilities of the monomer material.Simultaneously,layered carbon between Bi_(2)WO_(6)and TiO_(2)accelerated charge transfer and carrier separation.The optimized BWO/TiO_(2)@C exhibited superior performance,with an 84.03%degradation rate of tetracycline(TC)and a 44.2%removal rate of NO under visible light,representing 1.54 and 4.79 times the performance of the original Bi_(2)WO_(6),respectively.Intermediate species generated during the photocatalytic oxidation processes of TC and NO were identified using liquid chromatograph mass spectrometry(LC-MS)and in-situ DRIFTS.By combining electron paramagnetic resonance(EPR)and density functional theory(DFT)calculations,in-depth mechanisms were elucidated.This study sheds new light on the applications of Bi_(2)WO_(6)and MXene in photocatalysis,offering potential for the development of efficient dual-functional photocatalysts for addressing water and air pollution.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(NRF-2018R1A6A1A03024962)the Ministry of Science and ICT(NRF-2020R1A2C2100746).
文摘Developing an efficient electrocatalyst for superior electrochemical water splitting(EWS)is crucial for achieving comprehensive hydrogen production.A heterostructured electrocatalyst,free of noble metals,Ti_(3)C_(2)MXene nanosheet-integrated cobalt-doped nickel hydroxide(NHCoMX)composite was synthesized via a hydrothermal method.The abundant pores in the Ti_(3)C_(2)MXene nanosheet(MX)-integrated microarchitecture increased the number of active sites and facilitated charge transfer,thus enhancing electrocatalysis.Specifically,the MXenhanced charge transfer considerably transformed the microelectronic structure of cobalt-doped Ni(OH)2(NHCo),which promoted its hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Hence,as an EWS catalyst,NHCoMX exhibited an exceptional electrocatalytic activity,demonstrating OER and HER overpotentials of 310 mV and 73 mV,respectively,with low Tafel slopes of 65 mV dec^(-1)and 85 mV dec^(-1),respectively;it exhibited a current density of 10 mV cm^(-2)in 1.0 mol L^(-1)KOH,representing the closest efficiency to the noble state-of-the-art RuO2 and Pt/C catalyst.Furthermore,the developed electrocatalyst improved the activities of both HER and OER,leading to an overall EWS current density of 10 mA cm^(-2)at 1.72 V in an alkaline electrolyte with two electrodes.This study describes an efficient heterostructured NHCoMX composite electrocatalyst.It is significantly comparable to the noble state-of-the-art electrocatalysts and can be extended to fabricate resourceful catalysts for large-scale EWS applications.
基金supported by the National Natural Science Foundation of China(52174247,52477213,52401244 and 22302066)Science and Technology Innovation Program of Hunan Province(No.2022RC1088)+2 种基金Natural Science Foundation of Hunan Province(2023JJ40255)Zhejiang Provincial Natural Science Foundation of China(No.LQ24B020005)Scientific Research Foundation of Hunan Provincial Education Department(22B0599 and 23A0442).
文摘3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,excellent pseudocapacitance,and fast charging capabilities.However,searching for eco-friendly aqueous Ti_(3)C_(2)T_(x) MXene-based inks without additives and preventing severe restack of MXene nanosheets in high-concentration inks are significantly challenging.This study develops an additive-free,highly printable,viscosity adjustable,and environmentally friendly MXene/carbon nanotube(CNT)hybrid aqueous inks,in which the CNT can not only adjust the viscosity of Ti_(3)C_(2)T_(x) MXene inks but also widen the interlayer spacing of adjacent Ti_(3)C_(2)T_(x) MXene nanosheets effectively.The optimized MXene/CNT composite inks are successfully adopted to construct various configurations of MSCs with remarkable shape fidelity and geometric accuracy,together with enhanced surface area accessibility for electrons and ions diffusion.As a result,the constructed interdigital symmetrical MSCs demonstrate outstanding areal capacitance(1249.3 mF cm^(-2)),superior energy density(111μWh cm^(-2) at 0.4mWcm^(-2)),and high power density(8mWcm^(-2) at 47.1μWh cm^(-2)).Furthermore,a self-powered modular system of solar cells integrated with MXene/CNT-MSCs and pressure sensors is successfully tailored,simultaneously achieving efficient solar energy collection and real-time human activities monitoring.This work offers insight into the understanding of the role of CNTs in MXene/CNT ink.Moreover,it provides a new approach for preparing environmentally friendly MXene-based inks for the 3D printing of high-performance MSCs,contributing to the development of miniaturized,flexible,and self-powered printable electronic microsystems.
基金support from the Natural Science Foundation of Shanghai(23ZR1423800),Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(18SG35)Open Research Fund of Shanghai Key Laboratory of Green Chemistry and Chemical Processes(East China Normal University)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University.
文摘TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.
