Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully...Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.展开更多
Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycl...Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycling stability and reaction kinetics.To address these challenges,we designed a core–shell heterostructure(VONC-T,T represents temperature)composed of a VN core and a porous carbon shell.This structure was synthesized via in-situ construction,involving optimized ratio of coating a zinc-based zeolitic imidazolate framework(ZIF-8)onto a vanadium-based metal-organic framework(MIL-47(V)),followed by a thermal treatment.This process ensures a high degree of interfacial stability between the core and shell,effectively mitigating the structural variation of VN during irreversible phase transitions and enhancing the overall structural stability.During thermal driving,the volatilization of zinc within the shell layer created a porous channel effect,which facilitating Zn^(2+)diffusion.The enhancement of Zn²⁺diffusion strengthens the efficient conversion of VN to amorphous VOx,labeled as VONC-T-a,which provides more active sites and consequently results in a high specific capacity.The optimized heterostructure of VONC-900-a presented high reversible capacity of 387.2 mAh g^(−1)at 0.2 A g^(−1)and demonstrated excellent rate performance,achieving 274.5 mAh g^(−1)at 20 A g^(−1),while maintaining a capacity retention rate of 93.3%after 5000 cycles at 10 A g^(−1).Density functional theory calculations confirmed improved reaction kinetics in the core–shell structure.This study not only highlights the potential of amorphous vanadium oxide core–shell heterostructure for AZIBs but also provides new insights into the conversion mechanisms of VN.展开更多
Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of m...Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.展开更多
Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied...Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.展开更多
Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compac...Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.展开更多
Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with hig...Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.展开更多
Cation substitution in spinel cobaltites(e.g.,ACo2O4,in which A=Mn,Fe,Co,Ni,Cu,or Zn)is a promising strategy to precisely modulate their electronic structure/properties and thus improve the corresponding electrochemic...Cation substitution in spinel cobaltites(e.g.,ACo2O4,in which A=Mn,Fe,Co,Ni,Cu,or Zn)is a promising strategy to precisely modulate their electronic structure/properties and thus improve the corresponding electrochemical performance for water splitting.However,the fundamental principles and mechanisms are not fully understood.This research aims to systematically investigate the effects of cation substitution in spinel cobaltites derived from mixed-metal-organic frameworks on the oxygen evolution reaction(OER).Among the obtained ACo2O4 catalysts,FeCo2O4 showed excellent OER performance with a current density of 10 mA·cm^-2 at an overpotential of 164 mV in alkaline media.Both theoretical calculations and experimental results demonstrate that the Fe substitution in the crystal lattice of ACo2O4 can significantly accelerate charge transfer,thereby achieving enhanced electrochemical properties.The crystal field of spinel ACo2O4,which determines the valence states of cations A,is identified as the key factor to dictate the OER performance of these spinel cobaltites.展开更多
Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones suc...Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.展开更多
Flexible human–machine interfaces show broad prospects for next-generation flexible or wearable electronics compared with their currently available bulky and rigid counterparts.However,compared to their rigid counter...Flexible human–machine interfaces show broad prospects for next-generation flexible or wearable electronics compared with their currently available bulky and rigid counterparts.However,compared to their rigid counterparts,most reported flexible devices(e.g.,flexible loudspeakers and microphones)show inferior performance,mainly due to the nature of their flexibility.Therefore,it is of great significance to improve their performance by developing and optimizing new materials,structures and design methodologies.In this paper,a flexible acoustic platform based on a zinc oxide(ZnO)thin film on an aluminum foil substrate is developed and optimized;this platform can be applied as a loudspeaker,a microphone,or an ambient sensor depending on the selection of its excitation frequencies.When used as a speaker,the proposed structure shows a high sound pressure level(SPL)of~90 dB(with a standard deviation of~3.6 dB),a low total harmonic distortion of~1.41%,and a uniform directivity(with a standard deviation of~4 dB).Its normalized SPL is higher than those of similar devices reported in the recent literature.When used as a microphone,the proposed device shows a precision of 98%for speech recognition,and the measured audio signals show a strong similarity to the original audio signals,demonstrating its equivalent performance compared to a rigid commercial microphone.As a flexible sensor,this device shows a high temperature coefficient of frequency of−289 ppm/K and good performance for respiratory monitoring.展开更多
Exceptional point(EP)is referred to degeneracies in a non-Hermitian system where two or more eigenvalues and their corresponding eigenvectors coalesce.Recently there have been significantly increased interests in harn...Exceptional point(EP)is referred to degeneracies in a non-Hermitian system where two or more eigenvalues and their corresponding eigenvectors coalesce.Recently there have been significantly increased interests in harnessing EPs to enhance responsivities and achieve ultrasensitive detections in optics,electronics and acoustics,although there are few similar studies focused on using surface acoustic wave(SAW)sensing technologies,probably due to its great technical challenges.Herein,we proposed a scheme for accessing EPs in an on-chip architecture consisted of coupledSAW-resonators system,forming a passive parity-time(PT)symmetric system.We demonstrated that by tuning additional losses in one of resonators and regulating the system in the proximity of the EP,the sensor exhibited significantly enhanced responses.As an example,we present an EP-based SAW gas sensor,which showed a muchimproved sensitivity compared to that of a conventional delay-line SAW sensor.The fundamental mechanisms behind this excellent sensing performance have been elucidated.展开更多
Flexible surface acoustic wave(SAW)devices have recently attracted tremendous attention for their widespread application in sensing and microfluidics.However,for these applications,SAW devices often need to be bent in...Flexible surface acoustic wave(SAW)devices have recently attracted tremendous attention for their widespread application in sensing and microfluidics.However,for these applications,SAW devices often need to be bent into offaxis deformations between the acoustic wave propagation direction and bending direction.Currently,there are few studies on this topic,and the bending mechanisms during off-axis bending deformations have remained unexplored for multisensing applications.Herein,we fabricated aluminum nitride(AlN)flexible SAW devices by using high-quality AlN films deposited on flexible glass substrates and systematically investigated their complex deformation behaviors.A theoretical model was first developed using coupling wave equations and the boundary condition method to analyze the characteristics of the device with bending and off-axis deformation under elastic strains.The relationships between the frequency shifts of the SAW device and the bending strain and off-axis angle were obtained,and the results were identical to those from the theoretical calculations.Finally,we performed proof-of-concept demonstrations of its multisensing potential by monitoring human wrist movements at various off-axis angles and detecting UV light intensities on a curved surface,thus paving the way for the application of versatile flexible electronics.展开更多
For the purpose of stable performance in energy storage systems, a new hollow nanostructure of seasponge-C/SiC@SiC/C(SCS/SiC@SiC/C) has been successfully fabricated by the SCS/SiC nanospheres coated with SiC/C shells ...For the purpose of stable performance in energy storage systems, a new hollow nanostructure of seasponge-C/SiC@SiC/C(SCS/SiC@SiC/C) has been successfully fabricated by the SCS/SiC nanospheres coated with SiC/C shells through an in situ reduction process. Based on SCSs and the carbon shells, the stable hollow structures of SCS/SiC@SiC/C can contain large proportion of active SiC layers, which are adhered to both SCSs and the inner surfaces of carbon shells. Such nanostructured anode enables an excellent cycling stability with a capacity of 612 mAh/g at a current density of 0.5 A/g after 1,800 cycles, achieving an excellent stable Li^+-storage capability.展开更多
Current state-of-the-art stretchable/flexible sensors have received stringent demands on sensitivity,flexibility,linearity,and widerange measurement capability.Herein,we report a methodology of strain sensors based on...Current state-of-the-art stretchable/flexible sensors have received stringent demands on sensitivity,flexibility,linearity,and widerange measurement capability.Herein,we report a methodology of strain sensors based on graphene/Ecoflex composites by modulating multiscale/hierarchical wrinkles on flexible substrates.The sensor shows an ultra-high sensitivity with a gauge factor of 1078.1,a stretchability of 650%,a response time of~140 ms,and a superior cycling durability.It can detect wide-range physiological signals including vigorous body motions,pulse monitoring and speech recognition,and be used for monitoring of human respirations in real-time using a cloud platform,showing a great potential for the healthcare internet of things.Complex gestures/sign languages can be precisely detected.Human-machine interface is demonstrated by using a sensor-integrated glove to remotely control an external manipulator to remotely defuse a bomb.This study provides strategies for real-time/long-range medical diagnosis and remote assistance to perform dangerous tasks in industry and military fields.展开更多
There are great concerns for sensing using flexible acoustic wave sensors and lab-on-a-chip,as mechanical strains will dramatically change the sensing signals(e.g.,frequency)when they are bent during measurements.Thes...There are great concerns for sensing using flexible acoustic wave sensors and lab-on-a-chip,as mechanical strains will dramatically change the sensing signals(e.g.,frequency)when they are bent during measurements.These strain-induced signal changes cannot be easily separated from those of real sensing signals(e.g.,humidity,ultraviolet,or gas/biological molecules).Herein,we proposed a new strategy to minimize/eliminate the effects of mechanical bending strains by optimizing off-axis angles between the direction of bending deformation and propagation of acoustic waves on curved surfaces of layered piezoelectric film/flexible glass structure.This strategy has theoretically been proved by optimization of bending designs of off-axis angles and acoustically elastic effect.Proof-of-concept for humidity and ultraviolet-light sensing using flexible SAW devices with negligible interferences are achieved within a wide range of bending strains.This work provides the best solution for achieving high-performance flexible acoustic wave sensors under deformed/bending conditions.展开更多
Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications.However,the mechanical strains induced by random deformation of these flexible SAWs during...Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications.However,the mechanical strains induced by random deformation of these flexible SAWs during sensing often significantly alter the specific sensing signals,causing critical issues such as inconsistency of the sensing results on a curved/flexible surface.To address this challenge,we first developed high-performance AlScN piezoelectric filmbased flexible SAW sensors,investigated their response characteristics both theoretically and experimentally under various bending strains and UV illumination conditions,and achieved a high UV sensitivity of 1.71 KHz/(mW/cm^(2)).To ensure reliable and consistent UV detection and eliminate the interference of bending strain on SAW sensors,we proposed using key features within the response signals of a single flexible SAW device to establish a regression model based on machine learning algorithms for precise UV detection under dynamic strain disturbances,successfully decoupling the interference of bending strain from target UV detection.The results indicate that under strain interferences from 0 to 1160μεthe model based on the extreme gradient boosting algorithm exhibits optimal UV prediction performance.As a demonstration for practical applications,flexible SAW sensors were adhered to four different locations on spacecraft model surfaces,including flat and three curved surfaces with radii of curvature of 14.5,11.5,and 5.8 cm.These flexible SAW sensors demonstrated high reliability and consistency in terms of UV sensing performance under random bending conditions,with results consistent with those on a flat surface.展开更多
Surface acoustic wave(SAW)technology has been widely developed for ultraviolet(UV)detection due to its advantages of miniaturization,portability,potential to be integrated with microelectronics,and passive/wireless ca...Surface acoustic wave(SAW)technology has been widely developed for ultraviolet(UV)detection due to its advantages of miniaturization,portability,potential to be integrated with microelectronics,and passive/wireless capabilities.To enhance UV sensitivity,nanowires(NWs),such as ZnO,are often applied to enhance SAW-based UV detection due to their highly porous and interconnected 3D network structures and good UV sensitivity.However,ZnO NWs are normally hydrophilic,and thus,changes in environmental parameters such as humidity will significantly influence the detection precision and sensitivity of SAW-based UV sensors.To solve this issue,in this work,we proposed a new strategy using ZnO NWs wrapped with hydrophobic silica nanoparticles as the effective sensing layer.Analysis of the distribution and chemical bonds of these hydrophobic silica nanoparticles showed that numerous C-F bonds(which are hydrophobic)were found on the surface of the sensitive layer,which effectively blocked the adsorption of water molecules onto the ZnO NWs.This new sensing layer design minimizes the influence of humidity on the ZnO NW-based UV sensor within the relative humidity range of 10–70%.The sensor showed a UV sensitivity of 9.53 ppm(mW/cm^(2))^(−1),with high linearity(R^(2) value of 0.99904),small hysteresis(<1.65%)and good repeatability.This work solves the long-term dilemma of ZnO NW-based sensors,which are often sensitive to humidity changes.展开更多
Renewable electrical energy for electrolysis water can achieve green industrial chains for hydrogen production.However,finding efficient electrocatalysts remains a challenge for green hydrogen.Herein,sub-nanometric Fe...Renewable electrical energy for electrolysis water can achieve green industrial chains for hydrogen production.However,finding efficient electrocatalysts remains a challenge for green hydrogen.Herein,sub-nanometric FeCoP nanosheets with average thickness of 0.9 nm is constructed through 2D self-assembly driven by cavitation effect of ultrasonics and following phosphating.Benefiting from abundant active sites,enhanced H_(2)O molecular adsorption kinetics,and highly enhanced structural stability,the subcrystalline FeCoP shows excellent electrocatalytic activities of hydrogen evolution reaction(HER)and oxygen evolution reactions(OER).Ultralow overpotential of 37 mV is achieved at 10 mA·cm^(-2) for HER.When the FeCoP catalyst was used as both cathode and anode for overall water splitting using renewable electrical energy,green hydrogen produced is directly applied for hydrogen fuel cell to drive fan for more than 10 h.Theoretical calculation indicates that subcrystalline FeCoP more easily adsorbs H_(2)O than crystalline one and thus speeds up the kinetics of Volmer step in HER process.展开更多
基金This work was financially sup-ported by the National Natural Science Foundation of China(NSFC Nos:22171212,21771140,51771138,51979194)International Corporation Project of Shanghai Committee of Science and Technology by China(No.21160710300)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB4003801)the National Natural Science Foundation of China(No.52076091)We appreciate the analysis and characterization assistance of FESEM,XRD,and Raman from the Analytical and Testing Center at Huazhong University of Science&Technology.The author acknowledges the tubular furnace from Anhui Chem-n Instrument Co.,Ltd.
文摘Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycling stability and reaction kinetics.To address these challenges,we designed a core–shell heterostructure(VONC-T,T represents temperature)composed of a VN core and a porous carbon shell.This structure was synthesized via in-situ construction,involving optimized ratio of coating a zinc-based zeolitic imidazolate framework(ZIF-8)onto a vanadium-based metal-organic framework(MIL-47(V)),followed by a thermal treatment.This process ensures a high degree of interfacial stability between the core and shell,effectively mitigating the structural variation of VN during irreversible phase transitions and enhancing the overall structural stability.During thermal driving,the volatilization of zinc within the shell layer created a porous channel effect,which facilitating Zn^(2+)diffusion.The enhancement of Zn²⁺diffusion strengthens the efficient conversion of VN to amorphous VOx,labeled as VONC-T-a,which provides more active sites and consequently results in a high specific capacity.The optimized heterostructure of VONC-900-a presented high reversible capacity of 387.2 mAh g^(−1)at 0.2 A g^(−1)and demonstrated excellent rate performance,achieving 274.5 mAh g^(−1)at 20 A g^(−1),while maintaining a capacity retention rate of 93.3%after 5000 cycles at 10 A g^(−1).Density functional theory calculations confirmed improved reaction kinetics in the core–shell structure.This study not only highlights the potential of amorphous vanadium oxide core–shell heterostructure for AZIBs but also provides new insights into the conversion mechanisms of VN.
基金supported by the National Natural Science Foundation of China(Grant No.52175552)the National Key RD Program of China(Grant Nos.2022YFB3205400 and 2022YFB3204300).
文摘Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.
基金financially supported by the National Natural Science Foundation(No.22171212)the National Key Research and Development Program of China(No.2024YFC3908905)+1 种基金the International Exchange Grant(IEC/NSFC/201078)through the Royal Society UK and NSFCTriple boost strategy for low energy consuming catalytic ammonia synthesis(Trimonia)through UK EPSRC UK-HyRES Funding。
文摘Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.
基金This research is supported by the National Natural Science Foundation of China Grant(Nos.51705429&61801525)the Fundamental Research Funds for the Central Universities,Guangdong Natural Science Funds Grant(2018A030313400)+1 种基金Space Science and Technology Foundation,111 Project No.B13044UK Engineering and Physical Sciences Research Council(EPSRC)for support under grant EP/P018998/1,Newton Mobility Grant(IE161019)through Royal Society.
文摘Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.
基金financially supported by the National Natural Science Foundation(22171212)the Science and Technology Committee of Shanghai Municipality(21160710300,19DZ2271500)of Chinathe International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC。
文摘Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.
文摘Cation substitution in spinel cobaltites(e.g.,ACo2O4,in which A=Mn,Fe,Co,Ni,Cu,or Zn)is a promising strategy to precisely modulate their electronic structure/properties and thus improve the corresponding electrochemical performance for water splitting.However,the fundamental principles and mechanisms are not fully understood.This research aims to systematically investigate the effects of cation substitution in spinel cobaltites derived from mixed-metal-organic frameworks on the oxygen evolution reaction(OER).Among the obtained ACo2O4 catalysts,FeCo2O4 showed excellent OER performance with a current density of 10 mA·cm^-2 at an overpotential of 164 mV in alkaline media.Both theoretical calculations and experimental results demonstrate that the Fe substitution in the crystal lattice of ACo2O4 can significantly accelerate charge transfer,thereby achieving enhanced electrochemical properties.The crystal field of spinel ACo2O4,which determines the valence states of cations A,is identified as the key factor to dictate the OER performance of these spinel cobaltites.
基金supported by the Engineering and Physical Sciences Research Council(EPSRC)of the U.K.(Grant No.EP/P018998/1)the Acoustofluidics Special Interest Group of the UK Fluids Network(Grant No.EP/N032861/1)the EPSRC Centre for Doctoral Training in Renewable Energy Northeast Universities(ReNU)(Grant No.EP/S023836/1).
文摘Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.
基金supported by the“National Natural Science Foundation of China(NSFC 51875521,52175552,12104320)”the“Zhejiang Provincial Natural Science Foundation of China(LZ19E050002)”+7 种基金the Key Research and Development Program of Guangdong Province(Grant No.2020B0101040002)Special Projects in Key Fields of Colleges in Guangdong Province(2020ZDZX2007)Research Project in Fundamental and Application Fields of Guangdong Province(2020A1515110561)Guangdong Basic and Applied Basic Research Foundation(2019A1515111199)Shenzhen Science&Technology Project(Grant Nos.JCYJ20180507182106754,JCYJ20180507182439574,RCBS20200714114918249,GJHZ20200731095803010)the Engineering Physics and Science Research Council of UK(EPSRC 10 EP/P018998/1)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and the NSFCEPSRC NetworkPlus in Digitalized Surface Manufacturing(EP/S036180/1).
文摘Flexible human–machine interfaces show broad prospects for next-generation flexible or wearable electronics compared with their currently available bulky and rigid counterparts.However,compared to their rigid counterparts,most reported flexible devices(e.g.,flexible loudspeakers and microphones)show inferior performance,mainly due to the nature of their flexibility.Therefore,it is of great significance to improve their performance by developing and optimizing new materials,structures and design methodologies.In this paper,a flexible acoustic platform based on a zinc oxide(ZnO)thin film on an aluminum foil substrate is developed and optimized;this platform can be applied as a loudspeaker,a microphone,or an ambient sensor depending on the selection of its excitation frequencies.When used as a speaker,the proposed structure shows a high sound pressure level(SPL)of~90 dB(with a standard deviation of~3.6 dB),a low total harmonic distortion of~1.41%,and a uniform directivity(with a standard deviation of~4 dB).Its normalized SPL is higher than those of similar devices reported in the recent literature.When used as a microphone,the proposed device shows a precision of 98%for speech recognition,and the measured audio signals show a strong similarity to the original audio signals,demonstrating its equivalent performance compared to a rigid commercial microphone.As a flexible sensor,this device shows a high temperature coefficient of frequency of−289 ppm/K and good performance for respiratory monitoring.
基金supported by National Key R&D Program of China under Grant 2022YFE0103300 and 2020YFA0211400.
文摘Exceptional point(EP)is referred to degeneracies in a non-Hermitian system where two or more eigenvalues and their corresponding eigenvectors coalesce.Recently there have been significantly increased interests in harnessing EPs to enhance responsivities and achieve ultrasensitive detections in optics,electronics and acoustics,although there are few similar studies focused on using surface acoustic wave(SAW)sensing technologies,probably due to its great technical challenges.Herein,we proposed a scheme for accessing EPs in an on-chip architecture consisted of coupledSAW-resonators system,forming a passive parity-time(PT)symmetric system.We demonstrated that by tuning additional losses in one of resonators and regulating the system in the proximity of the EP,the sensor exhibited significantly enhanced responses.As an example,we present an EP-based SAW gas sensor,which showed a muchimproved sensitivity compared to that of a conventional delay-line SAW sensor.The fundamental mechanisms behind this excellent sensing performance have been elucidated.
基金This work was supported by the General Program of the National Natural Science Foundation of China(NSFC No.52075162)the Innovation Leading Program of New and High-tech Industry of Hunan Province(2020GK2015)+5 种基金The Natural Science Foundation of Hunan Province(2021JJ20018)the Natural Science Foundation of Changsha(kq2007026)the Key Research Project of Guangdong Province(2020B0101040002)NSFC-Zhejiang Joint Fund for the Integration of Industrialization anf information(No.U20A20172,U1909212)the Engineering Physics and Science Research Council of UK(EPSRC EP/P018998/1)the International Exchange Grant(IEC/NSFC/201078)through the Royal Society and NSFC.
文摘Flexible surface acoustic wave(SAW)devices have recently attracted tremendous attention for their widespread application in sensing and microfluidics.However,for these applications,SAW devices often need to be bent into offaxis deformations between the acoustic wave propagation direction and bending direction.Currently,there are few studies on this topic,and the bending mechanisms during off-axis bending deformations have remained unexplored for multisensing applications.Herein,we fabricated aluminum nitride(AlN)flexible SAW devices by using high-quality AlN films deposited on flexible glass substrates and systematically investigated their complex deformation behaviors.A theoretical model was first developed using coupling wave equations and the boundary condition method to analyze the characteristics of the device with bending and off-axis deformation under elastic strains.The relationships between the frequency shifts of the SAW device and the bending strain and off-axis angle were obtained,and the results were identical to those from the theoretical calculations.Finally,we performed proof-of-concept demonstrations of its multisensing potential by monitoring human wrist movements at various off-axis angles and detecting UV light intensities on a curved surface,thus paving the way for the application of versatile flexible electronics.
基金supported by the National Natural Science Foundation of China(21771140 and 51771138)UK Engineering and Physical Sciences Research Council(EPSRC,EP/P018998/1)
文摘For the purpose of stable performance in energy storage systems, a new hollow nanostructure of seasponge-C/SiC@SiC/C(SCS/SiC@SiC/C) has been successfully fabricated by the SCS/SiC nanospheres coated with SiC/C shells through an in situ reduction process. Based on SCSs and the carbon shells, the stable hollow structures of SCS/SiC@SiC/C can contain large proportion of active SiC layers, which are adhered to both SCSs and the inner surfaces of carbon shells. Such nanostructured anode enables an excellent cycling stability with a capacity of 612 mAh/g at a current density of 0.5 A/g after 1,800 cycles, achieving an excellent stable Li^+-storage capability.
基金supported by the NSFC (No.52075162)The Program of New and Hightech Industry of Hunan Province (2020GK2015)+4 种基金The Joint Fund Project of the Ministry of Education,The Excellent Youth Fund of Hunan Province (2021JJ20018)the Key Research&Development Program of Guangdong Province (2020B0101040002)the Natural Science Foundation of Changsha (kq2007026)the Engineering Physics and Science Research Council of UK (EPSRC EP/P018998/1)International Exchange Grant (IEC/NSFC/201078)through Royal Society and the NSFC.
文摘Current state-of-the-art stretchable/flexible sensors have received stringent demands on sensitivity,flexibility,linearity,and widerange measurement capability.Herein,we report a methodology of strain sensors based on graphene/Ecoflex composites by modulating multiscale/hierarchical wrinkles on flexible substrates.The sensor shows an ultra-high sensitivity with a gauge factor of 1078.1,a stretchability of 650%,a response time of~140 ms,and a superior cycling durability.It can detect wide-range physiological signals including vigorous body motions,pulse monitoring and speech recognition,and be used for monitoring of human respirations in real-time using a cloud platform,showing a great potential for the healthcare internet of things.Complex gestures/sign languages can be precisely detected.Human-machine interface is demonstrated by using a sensor-integrated glove to remotely control an external manipulator to remotely defuse a bomb.This study provides strategies for real-time/long-range medical diagnosis and remote assistance to perform dangerous tasks in industry and military fields.
基金supported by the Excellent Youth Fund of Hunan Province (2021JJ20018)the NSFC (No.52075162)+3 种基金the Program of New and High-tech Industry of Hunan Province (2020GK2015,2021GK4014)the Joint Fund Project of the Ministry of Educationthe Engineering Physics and Science Research Council of UK (EPSRC EP/P018998/1)International Exchange Grant (IEC/NSFC/201078)through Royal Society and the NSFC.
文摘There are great concerns for sensing using flexible acoustic wave sensors and lab-on-a-chip,as mechanical strains will dramatically change the sensing signals(e.g.,frequency)when they are bent during measurements.These strain-induced signal changes cannot be easily separated from those of real sensing signals(e.g.,humidity,ultraviolet,or gas/biological molecules).Herein,we proposed a new strategy to minimize/eliminate the effects of mechanical bending strains by optimizing off-axis angles between the direction of bending deformation and propagation of acoustic waves on curved surfaces of layered piezoelectric film/flexible glass structure.This strategy has theoretically been proved by optimization of bending designs of off-axis angles and acoustically elastic effect.Proof-of-concept for humidity and ultraviolet-light sensing using flexible SAW devices with negligible interferences are achieved within a wide range of bending strains.This work provides the best solution for achieving high-performance flexible acoustic wave sensors under deformed/bending conditions.
基金supported by the National Science Foundation of China(No.52075162)the Science and Technology Innovation Program of Hunan Province(2023RC3099).
文摘Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications.However,the mechanical strains induced by random deformation of these flexible SAWs during sensing often significantly alter the specific sensing signals,causing critical issues such as inconsistency of the sensing results on a curved/flexible surface.To address this challenge,we first developed high-performance AlScN piezoelectric filmbased flexible SAW sensors,investigated their response characteristics both theoretically and experimentally under various bending strains and UV illumination conditions,and achieved a high UV sensitivity of 1.71 KHz/(mW/cm^(2)).To ensure reliable and consistent UV detection and eliminate the interference of bending strain on SAW sensors,we proposed using key features within the response signals of a single flexible SAW device to establish a regression model based on machine learning algorithms for precise UV detection under dynamic strain disturbances,successfully decoupling the interference of bending strain from target UV detection.The results indicate that under strain interferences from 0 to 1160μεthe model based on the extreme gradient boosting algorithm exhibits optimal UV prediction performance.As a demonstration for practical applications,flexible SAW sensors were adhered to four different locations on spacecraft model surfaces,including flat and three curved surfaces with radii of curvature of 14.5,11.5,and 5.8 cm.These flexible SAW sensors demonstrated high reliability and consistency in terms of UV sensing performance under random bending conditions,with results consistent with those on a flat surface.
基金supported by the NSFC(No.52075162)the Program of New and High-tech Industry of Hunan Province(2020GK2015,2021GK4014)+3 种基金the Joint Fund Project of the Ministry of Education,the Excellent Youth Fund of Hunan Province(2021JJ20018)the Key Research&Development Program of Guangdong Province(2020B0101040002)the Engineering Physics and Science Research Council of UK(EPSRC EP/P018998/1)an International Exchange Grant(IEC/NSFC/201078)through the Royal Society and the NSFC.
文摘Surface acoustic wave(SAW)technology has been widely developed for ultraviolet(UV)detection due to its advantages of miniaturization,portability,potential to be integrated with microelectronics,and passive/wireless capabilities.To enhance UV sensitivity,nanowires(NWs),such as ZnO,are often applied to enhance SAW-based UV detection due to their highly porous and interconnected 3D network structures and good UV sensitivity.However,ZnO NWs are normally hydrophilic,and thus,changes in environmental parameters such as humidity will significantly influence the detection precision and sensitivity of SAW-based UV sensors.To solve this issue,in this work,we proposed a new strategy using ZnO NWs wrapped with hydrophobic silica nanoparticles as the effective sensing layer.Analysis of the distribution and chemical bonds of these hydrophobic silica nanoparticles showed that numerous C-F bonds(which are hydrophobic)were found on the surface of the sensitive layer,which effectively blocked the adsorption of water molecules onto the ZnO NWs.This new sensing layer design minimizes the influence of humidity on the ZnO NW-based UV sensor within the relative humidity range of 10–70%.The sensor showed a UV sensitivity of 9.53 ppm(mW/cm^(2))^(−1),with high linearity(R^(2) value of 0.99904),small hysteresis(<1.65%)and good repeatability.This work solves the long-term dilemma of ZnO NW-based sensors,which are often sensitive to humidity changes.
基金National Natural Science Foundation(NSFC)(No:22171212)Science and Technology Committee of Shanghai Municipality(Nos:21160710300,2022-4-YB-12)by China,and International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Renewable electrical energy for electrolysis water can achieve green industrial chains for hydrogen production.However,finding efficient electrocatalysts remains a challenge for green hydrogen.Herein,sub-nanometric FeCoP nanosheets with average thickness of 0.9 nm is constructed through 2D self-assembly driven by cavitation effect of ultrasonics and following phosphating.Benefiting from abundant active sites,enhanced H_(2)O molecular adsorption kinetics,and highly enhanced structural stability,the subcrystalline FeCoP shows excellent electrocatalytic activities of hydrogen evolution reaction(HER)and oxygen evolution reactions(OER).Ultralow overpotential of 37 mV is achieved at 10 mA·cm^(-2) for HER.When the FeCoP catalyst was used as both cathode and anode for overall water splitting using renewable electrical energy,green hydrogen produced is directly applied for hydrogen fuel cell to drive fan for more than 10 h.Theoretical calculation indicates that subcrystalline FeCoP more easily adsorbs H_(2)O than crystalline one and thus speeds up the kinetics of Volmer step in HER process.
