Herein,a novel Janus-structured multifunctional membrane with integrated electromagnetic interference(EMI)shielding and personalized thermal management is fabricated using shear-induced in situ fibrillation and vacuum...Herein,a novel Janus-structured multifunctional membrane with integrated electromagnetic interference(EMI)shielding and personalized thermal management is fabricated using shear-induced in situ fibrillation and vacuum-assisted filtration.Interestingly,within the polytetrafluoroethylene(PTFE)-carbon nanotube(CNT)-Fe_(3)O_(4)layer(FCFe),CNT nanofibers interweave with PTFE fibers to form a stable“silk-like”structure that effectively captures Fe_(3)O_(4)particles.By incorporating a highly conductive MXene layer,the FCFe/MXene(FCFe/M)membrane exhibits excellent electrical/thermal conductivity,mechanical properties,and flame retardancy.Impressively,benefiting from the rational regulation of component proportions and the design of a Janus structure,the FCFe/M membrane with a thickness of only 84.9μm delivers outstanding EMI shielding effectiveness of 44.56 dB in the X-band,with a normalized specific SE reaching 10,421.3 dB cm^(2)g^(-1),which is attributed to the“absorption-reflection-reabsorption”mechanism.Furthermore,the membrane demonstrates low-voltage-driven Joule heating and fast-response photothermal performance.Under the stimulation of a 3 V voltage and an optical power density of 320 mW cm^(-2),the surface temperatures of the FCFe/M membranes can reach up to 140.4 and 145.7℃,respectively.In brief,the FCFe/M membrane with anti-electromagnetic radiation and temperature regulation is an attractive candidate for the next generation of wearable electronics,EMI compatibility,visual heating,thermotherapy,and military and aerospace applications.展开更多
Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/ca...Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/carbon nanotube/polyimide(gradient-conductive MXene/CNT/PI,GCMCP)aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection.The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly(amic acid)inks with different CNT contents,where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer.In addition,the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections.Consequently,the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency(68.2 dB)and low reflection(R=0.23).Furthermore,the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission,which shows a prosperous application prospect in defense industry and aerospace.展开更多
药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催...药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催化材料,并探究了其对水体中卡马西平(CBZ)的光催化降解性能.通过X射线衍射、扫描电子显微镜和X射线光电子能谱表征,证明了g-C_(3)N_(4)与MXene的成功复合.同时,实验系统考察了pH值、CBZ初始浓度、催化剂用量和光强对光催化降解效果的影响.结果表明,在光照条件下,MCN催化体系对CBZ的去除效果最为显著,30 min内可去除超过90%的CBZ污染物.降解过程符合一级动力学模型,与g-C_(3)N_(4)相比,动力学常数提高3.3倍.稳态荧光光谱、瞬态光电流测试和电化学阻抗谱图结果表明,MXene的复合能提高g-C_(3)N_(4)中载流子的分离效率,从而促进更多活性氧物种的生成.自由基捕获实验和电子顺磁共振实验确认超氧自由基(·O_(2)^(-))在该催化反应中起主导作用.本研究的相关结果可为光催化降解PPCPs,尤其是卡马西平污染物提供新的策略.展开更多
Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional co...Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.展开更多
Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The m...Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The modified electrode was fabricated by drop casting of the GO-AuNPs,followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA.The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy(SEM)for each step of modification.The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode.In addition,the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate,which stimulate redox reaction on the modified electrode,thus improving the sensitivity of PQ analysis.The SPCE/GOAuNPs/P3ABA offered a wide linear range of PQ determination(10^(−9)-10^(−4) mol/L)and low limit of detection(LOD)of 0.45×10^(−9) mol/L or 0.116μg/L,which is far below international safety regulations.The modified electrode showed minimum interference effect with percent recovery ranging from 96.5%to 116.1%after addition of other herbicides,pesticides,metal ions,and additives.The stability of the SPCE/GO-AuNPs/P3ABA was evaluated,and the results indicated negligible changes in the detection signal over 9 weeks.Moreover,this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.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
The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of po...The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of poly(ethylene oxide)(PEO)droplets using a gold nanoparticle tracer,where the heterogeneous flow field in different regions was illustrated.This demonstrates that the gold nanoparticles at either the center or the edge regions of the droplet exhibit anisotropic kinematic behavior.At early stage,Marangoni backflow causes gold nanoparticles to move towards the edge firstly,and the circles back towards the droplet center after arriving the contact line with a sudden increase in z axis for 10.4μm,indicating the scale of the upward-moving microscopic flow vortices.This phenomenon does not occur in water droplets in the absence of polymers.The gold nanoparticles underwent Brownian-like motion at the center of the PEO droplet or water droplet owing to the low perturbation of the flow field.At the late stage of pinning of the PEO droplets,the motion showed multiple reverses in the direction of the gold nanoparticles,indicating the complexity of the flow field.This study enhances the understanding of the drying dynamics of polymer solution droplets and offers valuable insights into the fabrication of surface materials.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
Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene ma...Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene materials are predicted to be highly promising new thermoelectric materials.Here,we report a self-assembled flexible Ti_(3)C_(2)T_(x) MXenebased TCSC device,using prepared Ti_(3)C_(2)T_(x) MXene as the capacitor electrode and a NaClO_(4)/PEO gel as the electrolyte.We also explore the working mechanism of the TCSCs.The fabricated Ti_(3)C_(2)T_(x)-based TCSCs exhibit an excellent Seebeck coefficient of 11.8 mV∙K^(−1) on average and maintain good cycling stability under various temperature differences.Demonstrations of multiple practical applications show that Ti_(3)C_(2)T_(x) MXene-based TCSC devices are excellent candidates for self-powered integrated electronic devices.展开更多
Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed an...Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed and high dehydrogenation temperature.In this work,ultra-stable bimetallic MXene Mo_(2)V_(2)C_(3)was successfully synthesized and used to accelerate the hydrogen storage speed and reduce the dehydrogenation/hydrogenation temperature of MgH_(2).The MgH_(2)+10 wt%Mo_(2)V_(2)C_(3)sample starts dehydrogenation at 180℃and reaches the maximum dehydrogenation rate at 259℃.It also exhibits outstanding room-temperature(RT)rapid hydrogenation performance and cycling stability,retaining up to 100%capacity after 50 cycles at 300℃.Another interesting phenomenon is that the hydrogen storage speed of the sample is even faster without capacity decrease as the dehydrogenation/re-hydrogena tion cycle proceeds.First-principles calculations show that the Mg atoms are stabilized at the top sites of Mo atoms,and the Mg-H bonds that are adsorbed on Mo_(2)V_(2)C_(3)are more susceptible to breakage.The key to the accelerated rate of Mg/MgH_(2)hydrogenation/dehydrogenation is the enhancement of the interaction between Mg/MgH_(2)and Mo_(2)V_(2)C_(3)MXene with the increasing number of cycles,whereas the existence of the V renders the structure of MXene more stable.Our study refines the mechanistic understanding of bimetallic MXene catalyst for MgH_(2)hydrogen storage and expands reference on the type and preparation of bimetallic MXene.展开更多
基金support from the National Natural Science Foundation of China(NSFC,Grant No.52175341)Shandong Provincial Natural Science Foundation(Grant No.ZR2022JQ24)Funding Project of Jinan City’s New Twenty Items for Colleges and Universities(Grant No.202333038).
文摘Herein,a novel Janus-structured multifunctional membrane with integrated electromagnetic interference(EMI)shielding and personalized thermal management is fabricated using shear-induced in situ fibrillation and vacuum-assisted filtration.Interestingly,within the polytetrafluoroethylene(PTFE)-carbon nanotube(CNT)-Fe_(3)O_(4)layer(FCFe),CNT nanofibers interweave with PTFE fibers to form a stable“silk-like”structure that effectively captures Fe_(3)O_(4)particles.By incorporating a highly conductive MXene layer,the FCFe/MXene(FCFe/M)membrane exhibits excellent electrical/thermal conductivity,mechanical properties,and flame retardancy.Impressively,benefiting from the rational regulation of component proportions and the design of a Janus structure,the FCFe/M membrane with a thickness of only 84.9μm delivers outstanding EMI shielding effectiveness of 44.56 dB in the X-band,with a normalized specific SE reaching 10,421.3 dB cm^(2)g^(-1),which is attributed to the“absorption-reflection-reabsorption”mechanism.Furthermore,the membrane demonstrates low-voltage-driven Joule heating and fast-response photothermal performance.Under the stimulation of a 3 V voltage and an optical power density of 320 mW cm^(-2),the surface temperatures of the FCFe/M membranes can reach up to 140.4 and 145.7℃,respectively.In brief,the FCFe/M membrane with anti-electromagnetic radiation and temperature regulation is an attractive candidate for the next generation of wearable electronics,EMI compatibility,visual heating,thermotherapy,and military and aerospace applications.
基金the National Natural Science Foundation of China(52073053,52233006)Young Elite Scientists Sponsorship Program by CAST(2021QNRC001)+3 种基金Shanghai Rising-Star Program(21QA1400300)Innovation Program of Shanghai Municipal Education Commission(2021-01-0700-03-E00108)Science and Technology Commission of Shanghai Municipality(20520741100)China Postdoctoral Science Foundation(2021M690596)。
文摘Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/carbon nanotube/polyimide(gradient-conductive MXene/CNT/PI,GCMCP)aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection.The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly(amic acid)inks with different CNT contents,where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer.In addition,the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections.Consequently,the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency(68.2 dB)and low reflection(R=0.23).Furthermore,the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission,which shows a prosperous application prospect in defense industry and aerospace.
文摘药品和个人护理产品(Pharmaceuticals and Personal Care Products,PPCPs)在水环境中的存在对生态系统和人体健康构成了潜在威胁.光催化技术因其高效的催化氧化能力而备受关注.本研究采用煅烧法制备了g-C_(3)N_(4)/MXene(MCN)复合光催化材料,并探究了其对水体中卡马西平(CBZ)的光催化降解性能.通过X射线衍射、扫描电子显微镜和X射线光电子能谱表征,证明了g-C_(3)N_(4)与MXene的成功复合.同时,实验系统考察了pH值、CBZ初始浓度、催化剂用量和光强对光催化降解效果的影响.结果表明,在光照条件下,MCN催化体系对CBZ的去除效果最为显著,30 min内可去除超过90%的CBZ污染物.降解过程符合一级动力学模型,与g-C_(3)N_(4)相比,动力学常数提高3.3倍.稳态荧光光谱、瞬态光电流测试和电化学阻抗谱图结果表明,MXene的复合能提高g-C_(3)N_(4)中载流子的分离效率,从而促进更多活性氧物种的生成.自由基捕获实验和电子顺磁共振实验确认超氧自由基(·O_(2)^(-))在该催化反应中起主导作用.本研究的相关结果可为光催化降解PPCPs,尤其是卡马西平污染物提供新的策略.
文摘Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.
基金supported by the ProgramManagement Unit on Area Based Development (PMUA),Thailand (No.4594393)the National Science and Technology Development Agency (NSTDA),Thailand (No.P2250367).
文摘Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The modified electrode was fabricated by drop casting of the GO-AuNPs,followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA.The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy(SEM)for each step of modification.The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode.In addition,the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate,which stimulate redox reaction on the modified electrode,thus improving the sensitivity of PQ analysis.The SPCE/GOAuNPs/P3ABA offered a wide linear range of PQ determination(10^(−9)-10^(−4) mol/L)and low limit of detection(LOD)of 0.45×10^(−9) mol/L or 0.116μg/L,which is far below international safety regulations.The modified electrode showed minimum interference effect with percent recovery ranging from 96.5%to 116.1%after addition of other herbicides,pesticides,metal ions,and additives.The stability of the SPCE/GO-AuNPs/P3ABA was evaluated,and the results indicated negligible changes in the detection signal over 9 weeks.Moreover,this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.
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supported by the Key-Area Research and Development Program of Guangdong Province(No.2023B0101200006)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515011926)+1 种基金Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,Guangzhou 510640,China(South China University of Technology)(No.2023B1212060003)State Key Laboratory of Applied Microbiology Southern China(No.SKLAM008-2022)。
文摘The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of poly(ethylene oxide)(PEO)droplets using a gold nanoparticle tracer,where the heterogeneous flow field in different regions was illustrated.This demonstrates that the gold nanoparticles at either the center or the edge regions of the droplet exhibit anisotropic kinematic behavior.At early stage,Marangoni backflow causes gold nanoparticles to move towards the edge firstly,and the circles back towards the droplet center after arriving the contact line with a sudden increase in z axis for 10.4μm,indicating the scale of the upward-moving microscopic flow vortices.This phenomenon does not occur in water droplets in the absence of polymers.The gold nanoparticles underwent Brownian-like motion at the center of the PEO droplet or water droplet owing to the low perturbation of the flow field.At the late stage of pinning of the PEO droplets,the motion showed multiple reverses in the direction of the gold nanoparticles,indicating the complexity of the flow field.This study enhances the understanding of the drying dynamics of polymer solution droplets and offers valuable insights into the fabrication of surface materials.
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 National Natural Science Foundation of China(62474019)Beijing Natural Science Foundation(L223006).
文摘Thermally chargeable supercapacitors(TCSCs)have unique advantages in the collection,conversion,and storage of thermal energy,contributing to the development of new strategies for thermal energy utilization.2D MXene materials are predicted to be highly promising new thermoelectric materials.Here,we report a self-assembled flexible Ti_(3)C_(2)T_(x) MXenebased TCSC device,using prepared Ti_(3)C_(2)T_(x) MXene as the capacitor electrode and a NaClO_(4)/PEO gel as the electrolyte.We also explore the working mechanism of the TCSCs.The fabricated Ti_(3)C_(2)T_(x)-based TCSCs exhibit an excellent Seebeck coefficient of 11.8 mV∙K^(−1) on average and maintain good cycling stability under various temperature differences.Demonstrations of multiple practical applications show that Ti_(3)C_(2)T_(x) MXene-based TCSC devices are excellent candidates for self-powered integrated electronic devices.
基金supported by the National Key Research and Development Plan(2023YFB3809101)the National Natural Science Foundation of China(Grant nos.52471225,52201250,52271212,52401277)+1 种基金the Fundamental Research Funds for the Central Universities(2024MS084)the Double-First Class project for the NCEPU。
文摘Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed and high dehydrogenation temperature.In this work,ultra-stable bimetallic MXene Mo_(2)V_(2)C_(3)was successfully synthesized and used to accelerate the hydrogen storage speed and reduce the dehydrogenation/hydrogenation temperature of MgH_(2).The MgH_(2)+10 wt%Mo_(2)V_(2)C_(3)sample starts dehydrogenation at 180℃and reaches the maximum dehydrogenation rate at 259℃.It also exhibits outstanding room-temperature(RT)rapid hydrogenation performance and cycling stability,retaining up to 100%capacity after 50 cycles at 300℃.Another interesting phenomenon is that the hydrogen storage speed of the sample is even faster without capacity decrease as the dehydrogenation/re-hydrogena tion cycle proceeds.First-principles calculations show that the Mg atoms are stabilized at the top sites of Mo atoms,and the Mg-H bonds that are adsorbed on Mo_(2)V_(2)C_(3)are more susceptible to breakage.The key to the accelerated rate of Mg/MgH_(2)hydrogenation/dehydrogenation is the enhancement of the interaction between Mg/MgH_(2)and Mo_(2)V_(2)C_(3)MXene with the increasing number of cycles,whereas the existence of the V renders the structure of MXene more stable.Our study refines the mechanistic understanding of bimetallic MXene catalyst for MgH_(2)hydrogen storage and expands reference on the type and preparation of bimetallic MXene.
