The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality...The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality and renew-able energy conversion.However,there are few reports on the development of bi-functional catalysts for zinc-air bat-tery-driven CO_(2)RR devices.We introduce a novel approach for synthesizing Fe_(2)N/Fe_(3)C species embedded in nitrogen-doped carbon nanofibers by electrospinning a solution of Hemin and polyacrylonitrile in N,N-dimethylformamide.The material has an exceptional catalytic performance,with a half-wave potential of 0.91 V versus RHE for the ORR and values of over 90%for both the selectivity and Faradaic efficiency for the CO_(2)RR.The high catalytic performances are attrib-uted to the strong coupling between the Fe_(3)C/Fe_(2)N heterostructure and the Fe-N-C sites in the nitrogen-doped carbon nan-ofibers.Notably,both Fe_(3)C and Fe_(2)N play distinct roles in both the ORR and CO_(2)RR.This investigation indicates a way for designing advanced carbon-based bi-functional catalysts for use in this field.展开更多
Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic ...Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.展开更多
Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous ma...Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous material,metal–organic frameworks(MOF)can be used for gas separation and adsorption due to their adjustable pore size and acceptable thermal stability.In this work,the ZIF-71 MOF was synthesized on CuO nanofibers doped with different concentrations of Ru to form a Ru–CuO@ZIF-71 nanocomposite sensor,which was then used for H_(2)S detection.The sensor shows sensitivity to trace amounts of H_(2)S gas(100 ppb),and the response is greatly enhanced at the optimal Ru doping ratio and operating temperature.The introduction of the ZIF-71 membrane can significantly increase the selectivity of the sensor while further improving the sensitivity.Finally,the possible sensing mechanism of the Ru–CuO@ZIF-71 sensor was explored.The enhancement of the H_(2)S gas sensing properties may be attributed to the catalysis of Ru and the formation of the Schottky junction at the Ru–CuO interface.Besides,the calculation based on density functional theory reveals enhanced adsorption capacities of CuO for H_(2)S after Ru doping.Therefore,the Ru–CuO@ZIF-71 sensor has strong application potential in exhaled gas detection and portable detection of H_(2)S gas in industrial environments.展开更多
The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insuffic...The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.展开更多
Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofi...Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.展开更多
SnO2 nanofibers were synthesized by electrospinning and modified with Co3O4 via impregnation in this work. Chemical composition and morphology of the nanofibers were system- atically characterized, and their gas sensi...SnO2 nanofibers were synthesized by electrospinning and modified with Co3O4 via impregnation in this work. Chemical composition and morphology of the nanofibers were system- atically characterized, and their gas sensing properties were investigated. Results showed that Co3O4 modification significantly enhanced the sensing performance of SnO2 nanofibers to ethanol gas. For a sample with 1.2 mol% Co3O4, the response to 100 ppm ethanol was 38.0 at 300 ℃, about 6.7 times larger than that of SnO2 nanofibers. In addition, the response/recovery time was also greatly reduced. A power-law dependence of the sensor response on the ethanol concentration as well as excellent ethanol selectivity was observed for the Co3O4/SnO2 sensor. The enhanced ethanol sensing performance may be attributed to the formation of p-n heterojunctions between the two oxides.展开更多
The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fa...The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.展开更多
Antimony-based materials have become promising anodes within lithium-ion batteries(LIBs)due to their low cost and the high theoretical capacity.However,there is a potential to further enhance the electrochemical perfo...Antimony-based materials have become promising anodes within lithium-ion batteries(LIBs)due to their low cost and the high theoretical capacity.However,there is a potential to further enhance the electrochemical performance of such antimony-based materials.Herein,Sb2Se3@C nanofibers(Sb2Se3@CNFs)are designed and obtained via a novel electrospinning method.Upon electrochemically testing as an anode within LIBs,the Sb2Se3@CNFs(annealed at 600℃)delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles.Moreover,it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g.The excellent performance of the Sb2 Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials,but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion.The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.展开更多
In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treat...In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treatment.The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency.Ni/T-Nb_(2)O_(5)nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system,which provides effective buffering during the lithiation/delithiation process for cycling stability.The Ni/TNb_(2)O_(5)@CNFs show high surface area(26.321 m^(2)·g^(-1))and mesoporous microstructure,resulting in higher capacity and excellent rate performance.The Ni/T-Nb_(2)O_(5)@CNFs exhibit a remarkable capacity of 437 mAh·g^(-1)at a current density of0.5 A·g^(-1)after 230 cycles and a capacity of 173 mAh·g^(-1)at a current density up to 10.0 A·g^(-1)after 1400 cycles.This work indicates that nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs.展开更多
Porous TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO2/ZnCl2/PVP[PVP：polyvinyl pyrrolidone）]nanofibers,which were elec...Porous TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO2/ZnCl2/PVP[PVP：polyvinyl pyrrolidone）]nanofibers,which were electrospun from a mixture solution of TiO2,ZnCl2 and PVP.Transmission electron microscopy（TEM） and X-ray diffraction（XRD） analyses were used to identify the morphology of the TiO2/ZnO nanofibers and a formation of inorganic TiO2/ZnO fibers.The porous structure of the TiO2/ZnO fibers was characterized by N2 adsoption/desorption isotherm.Surface photovoltage spectroscopy（SPS） and photocatalytic activity measurements revealed advance properties of the porous TiO2/ZnO composite nanofibers and the results were compared with pure TiO2 nanofibers,pure ZnO nanofibers and TiO2/ZnO nanoparticles.展开更多
Pseudo-capacitive mechanisms can provide higher energy densities than electrical double-layer capacitors while being faster than bulk storage mechanisms.Usually,they suffer from low intrinsic electronic and ion conduc...Pseudo-capacitive mechanisms can provide higher energy densities than electrical double-layer capacitors while being faster than bulk storage mechanisms.Usually,they suffer from low intrinsic electronic and ion conductivities of the active materials.Here,taking advantage of the combination of TiS2 decoration,sulfur doping,and a nanometer-sized structure,as-spun TiO2/C nanofiber composites are developed that enable rapid transport of sodium ions and electrons,and exhibit enhanced pseudo-capacitively dominated capacities.At a scan rate of 0.5 mV s−1,a high pseudo-capacitive contribution(76%of the total storage)is obtained for the S-doped TiS2/TiO2/C electrode(termed as TiS2/S-TiO2/C).Such enhanced pseudocapacitive activity allows rapid chemical kinetics and significantly improves the high-rate sodium storage performance of TiO2.The TiS2/S-TiO2/C composite electrode delivers a high capacity of 114 mAh g−1 at a current density of 5000 mA g−1.The capacity maintains at high level(161 mAh g−1)even after 1500 cycles and is still characterized by 58 mAh g−1 at the extreme condition of 10,000 mA g−1 after 10,000 cycles.展开更多
TiO2/Bi4 Ti3 O12 hybrids have been widely prepared as promising photocatalysts for decomposing organic contaminations.However,the insufficient visible light absorption and low charge separation efficiency lead to thei...TiO2/Bi4 Ti3 O12 hybrids have been widely prepared as promising photocatalysts for decomposing organic contaminations.However,the insufficient visible light absorption and low charge separation efficiency lead to their poor photocatalytic activity.Herein,a robust methodology to construct novel TiO2/Bi4 Ti3 O12/MoS2 core/shell structures as visible light photocatalysts is presented.Homogeneous bismuth oxyiodide(BiOI) nanoplates were immobilized on electrospun TiO2 nanofiber surface by successive ionic layer adsorption and reaction(SILAR) method.TiO2/Bi4 Ti3 O12 core/shell nanofibers were conveniently prepared by partial conversion of TiO2 to high crystallized Bi4 Ti3 O12 shells through a solid-state reaction with BiOI nanoplates,which is accompanied with certain transition of TiO2 from anatase to rutile phase.Afterwards,MoS2 nanosheets with several layers thick were uniform decorated on the TiO2/Bi4 TiO3 O12 fiber surface resulting in TiO2/Bi4 Ti3 O12/MoS2 structures.Significant enhancement of visible light absorption and photo-generated charge separation of TiO2/Bi4 Ti3 O12 were achieved by introduction of MoS2.As a result,the optimized TiO2/Bi4 Ti3 O12/MoS2-2 presents 60% improvement for photodegrading RhB after 120 min irradiation under visible light and 3 times higher of apparent reaction rate constant in compared with the TiO2/Bi4 Ti3 O12.This synthetic method can also be used to establish other photocatalysts simply at low cost,therefore,is suitable for practical applications.展开更多
Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater...Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In2O3)nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process.Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers.The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS)technique.The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity.The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles,the applied power to raise the temperature of a sensing part and the kind of target gases.展开更多
One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal charact...One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal characteristics.Electrospinning is a straightforward and versatile method to prepare 1D SNFs with programmable structures,manageable dimensions,and modifiable properties,which hold great potential in many cutting-edge applications including aerospace,nanodevice,and energy.In this review,substantial advances in the structural design,controllable synthesis,and multifunctional applications of electrospun SNFs are highlighted.We begin with a brief introduction to the fundamental principles,available raw materials,and typical apparatus of electrospun SNFs.We then discuss the strategies for preparing SNFs with diverse structures in detail,especially stressing the newly emerging three-dimensional SiO_(2) nanofibrous aerogels.We continue with focus on major breakthroughs about brittleness-to-flexibility transition of SNFs and the means to achieve their mechanical reinforcement.In addition,we showcase recent applications enabled by electrospun SNFs,with particular emphasis on physical protection,health care and water treatment.In the end,we summarize this review and provide some perspectives on the future development direction of electrospun SNFs.展开更多
N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-di...N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-dimensional （3-D） network structure, which endows they promising candidate for anode ma- terials of lithium ion battery. The coaxial property of CNTs@α-Fe_2O_3@C nanofibers could significantly improve the cycling and rate performance owing to the acceleration of charge/electron transfer, improve- ment of conductivity, maintaining of structural integrity and inhibiting the aggregation. The α-Fe_2O_3 nanoparticles with small size and high percentage of N-doped amount could further improve the elec- trochemical performance. As for the CNTs@α-Fe_2O_3@C nanofibers, the capacity presented a high value of 1255.4 mAh/g at 0.1 C, and retained at 1213.4 mAh/g after 60 cycles. Even at high rate of 5 C, the ca- pacity still exhibited as high as 319 mAh/g. The results indicated that the synthesized N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers exhibited high cvcling and rate oerformance.展开更多
Wearable and portable mobile phones play a critical role in the market, and one of the key technologies is the flexible electrode with high specific capacity and excellent mechanical flexibility. Herein, a wire-in-wir...Wearable and portable mobile phones play a critical role in the market, and one of the key technologies is the flexible electrode with high specific capacity and excellent mechanical flexibility. Herein, a wire-in-wire TiO_(2)/C nanofibers (TiO_(2) ww/CN) film is synthesized via electrospinning with selenium as a structural inducer. The interconnected carbon network and unique wire- in-wire nanostructure cannot only improve electronic conductivity and induce effective charge transports, but also bring a superior mechanic flexibility. Ulti-mately, TiO_(2) ww/CN film shows outstanding electrochemical performance as free-standing electrodes in Li/K ion batteries. It shows a discharge capacity as high as 303 mAh g^(−1) at 5 A g^(−1) after 6000 cycles in Li half-cells, and the unique structure is well-reserved after long-term cycling. Moreover, even TiO_(2) has a large diffusion barrier of K^(+), TiO_(2) ww/CN film demonstrates excellent perfor-mance (259 mAh g^(−1) at 0.05 A g^(−1) after 1000 cycles) in K half-cells owing to extraordinary pseudocapacitive contribution. The Li/K full cells consisted of TiO_(2) ww/CN film anode and LiFePO_(4)/Perylene-3,4,9,10-tetracarboxylic dianhydride cathode possess outstanding cycling stability and demonstrate practical application from lighting at least 19 LEDs. It is, therefore, expected that this material will find broad applications in portable and wearable Li/K-ion batteries.展开更多
Lithium (Li) metal batteries have attracted much attention owing to its ultra-high energy density.However,as important part of Li metal batteries,Li anodes still face many challenges,mainly including uncontrolled dend...Lithium (Li) metal batteries have attracted much attention owing to its ultra-high energy density.However,as important part of Li metal batteries,Li anodes still face many challenges,mainly including uncontrolled dendritic Li formation,dramatical volume variation and serious pulverization.Herein,manganese dioxide (MnO_(2)) nanosheet modified nitrogen (N),phosphorus (P) co-doping carbon nanofibers(NPC) on carbon cloth (CC)(MnO_(2)@NPC-CC) is successfully fabricated through electrodeposition approach and further treated with Li by the molten-infusion method to prepare Li based Mn@NPC-CC(Li-Mn@NPC-CC) electrode.The synergy of MnO_(2) and NPC obviously increases the reaction rate between MnO_(2)@NPC-CC and Li and guides even Li distribution over infusion process.Additionally,theoretical calculation,simulation and experimental results further indicate that N,P,Mn multi-doping effectively improves the superior lithiophilicity of Li-Mn@NPC-CC,which induces uniform Li deposition/dissolution to suppress dendrite growth over cycles.Moreover,conductive and porous NPC matrix not only effectively improves the stability of Li-Mn@NPC-CC,but also provides abundant spaces to accelerate the transfer of ion/electron and buffer electrode dimension variation during cycling.Hence,Li-Mn@NPC-CC-based symmetric cells exhibit extra-long cycling life (over 2200 h) with small hysteresis of 20 mV.When the LiMn@NPC-CC anode couples with air,Li iron phosphate (LiFePO_(4)),or hard carbon (C) cathode,the assembled full cells exhibit outstanding performance with low hysteresis and stable cycling properties.Especially,the corresponding pouch-typed Li–air cells also exhibit good performance at different bending angles and even power a series of electronic devices.展开更多
In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanof...In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanofibers were characterized by dynamic light scattering（DLS）, UV–Vis spectroscopy,photoluminescence（PL） spectra, X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The SnOnanofibers deposited on fluorine-doped tin oxide（SnO） and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum（Pt） counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage（Voc）of 0.80 V, and a photocurrent density（JSC） of 3.70 m A/cmwere obtained for cells with SnOthickness of5–6 μm and cell area of 0.25 cmunder standard 1 Sun illumination（100 m W/cm）. The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.展开更多
SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers ...SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers are characterized by using field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),x-ray diffraction(XRD),and x-ray photoelectron spectrometer(XPS).The analyses of SnO_(2)/Co_(3)O_(4)NFs by EDS and HRTEM show that the cobalt and tin exist on one nanofiber,which is related to the homopolar electrospinning and the crystallization during sintering.As a typical n-type semiconductor,Sn O_(2)has the disadvantages of high optimal operating temperature and poor reproducibility.Comparing with Sn O_(2),the optimal operating temperature of SnO_(2)/Co_(3)O_(4)NFs is reduced from 350℃to 250℃,which may be related to the catalysis of Co_(2)O_(2).The response of SnO_(2)/Co_(3)O_(4)to 100-ppm ethanol at 250℃is 50.9,9 times higher than that of pure Sn O_(2),which may be attributed to the p–n heterojunction between the n-type Sn O_(2)crystalline grain and the p-type Co_(2)O_(2)crystalline grain.The nanoscale p–n heterojunction promotes the electron migration and forms an interface barrier.The synergy effects between Sn O_(2)and Co_(2)O_(2),the crystalline grain p–n heterojunction,the existence of nanofibers and the large specific surface area all jointly contribute to the improved gas sensing performance.展开更多
Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performanc...Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.展开更多
文摘The need for bi-functional catalysts that facilit-ate both the oxygen reduction(ORR)and carbon dioxide re-duction(CO_(2)RR)reactions arises from their potential to help solve the critical problems of carbon neutrality and renew-able energy conversion.However,there are few reports on the development of bi-functional catalysts for zinc-air bat-tery-driven CO_(2)RR devices.We introduce a novel approach for synthesizing Fe_(2)N/Fe_(3)C species embedded in nitrogen-doped carbon nanofibers by electrospinning a solution of Hemin and polyacrylonitrile in N,N-dimethylformamide.The material has an exceptional catalytic performance,with a half-wave potential of 0.91 V versus RHE for the ORR and values of over 90%for both the selectivity and Faradaic efficiency for the CO_(2)RR.The high catalytic performances are attrib-uted to the strong coupling between the Fe_(3)C/Fe_(2)N heterostructure and the Fe-N-C sites in the nitrogen-doped carbon nan-ofibers.Notably,both Fe_(3)C and Fe_(2)N play distinct roles in both the ORR and CO_(2)RR.This investigation indicates a way for designing advanced carbon-based bi-functional catalysts for use in this field.
基金financially supported by the National Natural Science Foundation of China(22278348)Natural Science Foundation of Xinjiang Autonomous Region(2022D01D05)+1 种基金National guidance for local projects of Xinjiang Autonomous Region(ZYYD2025JD09)Tianshan Leading technology talents Program of Xinjiang Autonomous Region。
文摘Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.
基金supported by the National Natural Science Foundation of China(Nos.52003297 and 22302233)the Open Project of State Key Laboratory of Chemical Safety(No.SKLCS-2024020)+2 种基金the National Key R&D Program of China(Nos.2022YFB3205501 and 2022YFB3205504)and the Fundamental Research Funds for the Central Universities(No.24CX02014A)the Fund of State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China).
文摘Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous material,metal–organic frameworks(MOF)can be used for gas separation and adsorption due to their adjustable pore size and acceptable thermal stability.In this work,the ZIF-71 MOF was synthesized on CuO nanofibers doped with different concentrations of Ru to form a Ru–CuO@ZIF-71 nanocomposite sensor,which was then used for H_(2)S detection.The sensor shows sensitivity to trace amounts of H_(2)S gas(100 ppb),and the response is greatly enhanced at the optimal Ru doping ratio and operating temperature.The introduction of the ZIF-71 membrane can significantly increase the selectivity of the sensor while further improving the sensitivity.Finally,the possible sensing mechanism of the Ru–CuO@ZIF-71 sensor was explored.The enhancement of the H_(2)S gas sensing properties may be attributed to the catalysis of Ru and the formation of the Schottky junction at the Ru–CuO interface.Besides,the calculation based on density functional theory reveals enhanced adsorption capacities of CuO for H_(2)S after Ru doping.Therefore,the Ru–CuO@ZIF-71 sensor has strong application potential in exhaled gas detection and portable detection of H_(2)S gas in industrial environments.
基金supported by the National Natural Science Foundation of China(22222601 and 22076019)the Fundamental Research Funds for the Central Universities(DUT23LAB611).
文摘The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.
文摘Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.
基金This work was supported by the National Natural Science Foundation of China （No.U1432108） and the Fundamental Research Funds for the Central Universities （No.WK2320000034）.
文摘SnO2 nanofibers were synthesized by electrospinning and modified with Co3O4 via impregnation in this work. Chemical composition and morphology of the nanofibers were system- atically characterized, and their gas sensing properties were investigated. Results showed that Co3O4 modification significantly enhanced the sensing performance of SnO2 nanofibers to ethanol gas. For a sample with 1.2 mol% Co3O4, the response to 100 ppm ethanol was 38.0 at 300 ℃, about 6.7 times larger than that of SnO2 nanofibers. In addition, the response/recovery time was also greatly reduced. A power-law dependence of the sensor response on the ethanol concentration as well as excellent ethanol selectivity was observed for the Co3O4/SnO2 sensor. The enhanced ethanol sensing performance may be attributed to the formation of p-n heterojunctions between the two oxides.
基金supported by the National Natural Science Foundation of China(21707173,51872341,51572209)the Science and Technology Program of Guangzhou(201707010095)+2 种基金the Start-up Funds for High-Level Talents of Sun Yat-sen University(38000-31131103)the Fundamental Research Funds for the Central Universities(19lgzd29)the China Postdoctoral Science Foundation(2017M622869)~~
文摘The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.
基金supported by the National Natural Science Foundation of China(No.51302079)the Natural Science Foundation of Hunan Province(No.2017JJ1008)。
文摘Antimony-based materials have become promising anodes within lithium-ion batteries(LIBs)due to their low cost and the high theoretical capacity.However,there is a potential to further enhance the electrochemical performance of such antimony-based materials.Herein,Sb2Se3@C nanofibers(Sb2Se3@CNFs)are designed and obtained via a novel electrospinning method.Upon electrochemically testing as an anode within LIBs,the Sb2Se3@CNFs(annealed at 600℃)delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles.Moreover,it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g.The excellent performance of the Sb2 Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials,but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion.The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.
基金the National Natural Science Foundation of China(Nos.51771236,51901249,U1904216)the Science Fund for Distinguished Young Scholars of Hunan Province(No.2018JJ1038)。
文摘In this work,nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in mesoporous carbon nanofibers(denoted as Ni/T-Nb_(2)O_(5)@CNFs)are successfully prepared through a simple electrospinning route and succedent heating treatment.The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency.Ni/T-Nb_(2)O_(5)nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system,which provides effective buffering during the lithiation/delithiation process for cycling stability.The Ni/TNb_(2)O_(5)@CNFs show high surface area(26.321 m^(2)·g^(-1))and mesoporous microstructure,resulting in higher capacity and excellent rate performance.The Ni/T-Nb_(2)O_(5)@CNFs exhibit a remarkable capacity of 437 mAh·g^(-1)at a current density of0.5 A·g^(-1)after 230 cycles and a capacity of 173 mAh·g^(-1)at a current density up to 10.0 A·g^(-1)after 1400 cycles.This work indicates that nickel/T-Nb_(2)O_(5)nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs.
基金supported in part by the National Natural Science Foundation of China(Nos.50473008 and 50673034)by Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.09KJD 150001)by DuPont Company through a Young Faculty Grant Award to Prof.C.Wang,and by Headwater Nanokinetix,Inc
文摘Porous TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO2/ZnCl2/PVP[PVP：polyvinyl pyrrolidone）]nanofibers,which were electrospun from a mixture solution of TiO2,ZnCl2 and PVP.Transmission electron microscopy（TEM） and X-ray diffraction（XRD） analyses were used to identify the morphology of the TiO2/ZnO nanofibers and a formation of inorganic TiO2/ZnO fibers.The porous structure of the TiO2/ZnO fibers was characterized by N2 adsoption/desorption isotherm.Surface photovoltage spectroscopy（SPS） and photocatalytic activity measurements revealed advance properties of the porous TiO2/ZnO composite nanofibers and the results were compared with pure TiO2 nanofibers,pure ZnO nanofibers and TiO2/ZnO nanoparticles.
基金This work was financially supported by National Key R&D Program of China(No.2018YFB0905400)the National Natural Science Foundation of China(Nos.51925207,51872277,and U1910210)+2 种基金Dalian National Laboratory For Clean Energy(DNL)Cooperation Fund,the CAS(DNL180310)the Fundamental Research Funds for the Central Universities(Wk2060140026)Sofja Kovalevskaja award of the Humboldt Society.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No.823717-ESTEEM3.
文摘Pseudo-capacitive mechanisms can provide higher energy densities than electrical double-layer capacitors while being faster than bulk storage mechanisms.Usually,they suffer from low intrinsic electronic and ion conductivities of the active materials.Here,taking advantage of the combination of TiS2 decoration,sulfur doping,and a nanometer-sized structure,as-spun TiO2/C nanofiber composites are developed that enable rapid transport of sodium ions and electrons,and exhibit enhanced pseudo-capacitively dominated capacities.At a scan rate of 0.5 mV s−1,a high pseudo-capacitive contribution(76%of the total storage)is obtained for the S-doped TiS2/TiO2/C electrode(termed as TiS2/S-TiO2/C).Such enhanced pseudocapacitive activity allows rapid chemical kinetics and significantly improves the high-rate sodium storage performance of TiO2.The TiS2/S-TiO2/C composite electrode delivers a high capacity of 114 mAh g−1 at a current density of 5000 mA g−1.The capacity maintains at high level(161 mAh g−1)even after 1500 cycles and is still characterized by 58 mAh g−1 at the extreme condition of 10,000 mA g−1 after 10,000 cycles.
基金supported financially by the National Natural Science Foundation of China(Nos.21501140,21403165,51372197)the Outstanding Youth Science Fund of Xi’an University of Science and Technology(No.2019YQ2-06)the Key Innovation Team of Shaanxi Province(No.2014KCT-04)。
文摘TiO2/Bi4 Ti3 O12 hybrids have been widely prepared as promising photocatalysts for decomposing organic contaminations.However,the insufficient visible light absorption and low charge separation efficiency lead to their poor photocatalytic activity.Herein,a robust methodology to construct novel TiO2/Bi4 Ti3 O12/MoS2 core/shell structures as visible light photocatalysts is presented.Homogeneous bismuth oxyiodide(BiOI) nanoplates were immobilized on electrospun TiO2 nanofiber surface by successive ionic layer adsorption and reaction(SILAR) method.TiO2/Bi4 Ti3 O12 core/shell nanofibers were conveniently prepared by partial conversion of TiO2 to high crystallized Bi4 Ti3 O12 shells through a solid-state reaction with BiOI nanoplates,which is accompanied with certain transition of TiO2 from anatase to rutile phase.Afterwards,MoS2 nanosheets with several layers thick were uniform decorated on the TiO2/Bi4 TiO3 O12 fiber surface resulting in TiO2/Bi4 Ti3 O12/MoS2 structures.Significant enhancement of visible light absorption and photo-generated charge separation of TiO2/Bi4 Ti3 O12 were achieved by introduction of MoS2.As a result,the optimized TiO2/Bi4 Ti3 O12/MoS2-2 presents 60% improvement for photodegrading RhB after 120 min irradiation under visible light and 3 times higher of apparent reaction rate constant in compared with the TiO2/Bi4 Ti3 O12.This synthetic method can also be used to establish other photocatalysts simply at low cost,therefore,is suitable for practical applications.
基金supported financially by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2017R1D1A1B03030796).
文摘Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In2O3)nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process.Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers.The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS)technique.The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity.The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles,the applied power to raise the temperature of a sensing part and the kind of target gases.
基金This work was supported by the National Natural Science Foundation of China(Nos.21961132024,51925302,and 52173055)the Ministry of Science and Technology of China(No.2021YFE0105100)the Fundamental Research Funds for the Central Universities and the DHU Distinguished Young Professor Program(No.LZA2020001).
文摘One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal characteristics.Electrospinning is a straightforward and versatile method to prepare 1D SNFs with programmable structures,manageable dimensions,and modifiable properties,which hold great potential in many cutting-edge applications including aerospace,nanodevice,and energy.In this review,substantial advances in the structural design,controllable synthesis,and multifunctional applications of electrospun SNFs are highlighted.We begin with a brief introduction to the fundamental principles,available raw materials,and typical apparatus of electrospun SNFs.We then discuss the strategies for preparing SNFs with diverse structures in detail,especially stressing the newly emerging three-dimensional SiO_(2) nanofibrous aerogels.We continue with focus on major breakthroughs about brittleness-to-flexibility transition of SNFs and the means to achieve their mechanical reinforcement.In addition,we showcase recent applications enabled by electrospun SNFs,with particular emphasis on physical protection,health care and water treatment.In the end,we summarize this review and provide some perspectives on the future development direction of electrospun SNFs.
基金the National Natural Science Foundation of China (No. 91634108, 21376148 and 61503246)National Key Program(2017FYA0205300)
文摘N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-dimensional （3-D） network structure, which endows they promising candidate for anode ma- terials of lithium ion battery. The coaxial property of CNTs@α-Fe_2O_3@C nanofibers could significantly improve the cycling and rate performance owing to the acceleration of charge/electron transfer, improve- ment of conductivity, maintaining of structural integrity and inhibiting the aggregation. The α-Fe_2O_3 nanoparticles with small size and high percentage of N-doped amount could further improve the elec- trochemical performance. As for the CNTs@α-Fe_2O_3@C nanofibers, the capacity presented a high value of 1255.4 mAh/g at 0.1 C, and retained at 1213.4 mAh/g after 60 cycles. Even at high rate of 5 C, the ca- pacity still exhibited as high as 319 mAh/g. The results indicated that the synthesized N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers exhibited high cvcling and rate oerformance.
基金the National Natural Science Foundation of China(Grant Nos.51672234,52072325)the Key Research Foundation of Education Bureau of Hunan Province,China(Grant No.20A486)+1 种基金Hunan 2011 Collaborative Innovation Center of Chemical Engineering and Technology with Environmental Benignity and Effective Resource Utilization,Program for Innovative Research Cultivation Team in University of Ministry of Education of China(1337304)the 111 Project(B12015).
文摘Wearable and portable mobile phones play a critical role in the market, and one of the key technologies is the flexible electrode with high specific capacity and excellent mechanical flexibility. Herein, a wire-in-wire TiO_(2)/C nanofibers (TiO_(2) ww/CN) film is synthesized via electrospinning with selenium as a structural inducer. The interconnected carbon network and unique wire- in-wire nanostructure cannot only improve electronic conductivity and induce effective charge transports, but also bring a superior mechanic flexibility. Ulti-mately, TiO_(2) ww/CN film shows outstanding electrochemical performance as free-standing electrodes in Li/K ion batteries. It shows a discharge capacity as high as 303 mAh g^(−1) at 5 A g^(−1) after 6000 cycles in Li half-cells, and the unique structure is well-reserved after long-term cycling. Moreover, even TiO_(2) has a large diffusion barrier of K^(+), TiO_(2) ww/CN film demonstrates excellent perfor-mance (259 mAh g^(−1) at 0.05 A g^(−1) after 1000 cycles) in K half-cells owing to extraordinary pseudocapacitive contribution. The Li/K full cells consisted of TiO_(2) ww/CN film anode and LiFePO_(4)/Perylene-3,4,9,10-tetracarboxylic dianhydride cathode possess outstanding cycling stability and demonstrate practical application from lighting at least 19 LEDs. It is, therefore, expected that this material will find broad applications in portable and wearable Li/K-ion batteries.
基金funding support from the National Natural Science Foundation of China (21905151 and 51772162)the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions, China (2019KJC004)+1 种基金the Outstanding Youth Foundation of Shandong Province, China (ZR2019JQ14)the Taishan Scholar Young Talent Program, Major Scientific and Technological Innovation Project (2019JZZY020405)。
文摘Lithium (Li) metal batteries have attracted much attention owing to its ultra-high energy density.However,as important part of Li metal batteries,Li anodes still face many challenges,mainly including uncontrolled dendritic Li formation,dramatical volume variation and serious pulverization.Herein,manganese dioxide (MnO_(2)) nanosheet modified nitrogen (N),phosphorus (P) co-doping carbon nanofibers(NPC) on carbon cloth (CC)(MnO_(2)@NPC-CC) is successfully fabricated through electrodeposition approach and further treated with Li by the molten-infusion method to prepare Li based Mn@NPC-CC(Li-Mn@NPC-CC) electrode.The synergy of MnO_(2) and NPC obviously increases the reaction rate between MnO_(2)@NPC-CC and Li and guides even Li distribution over infusion process.Additionally,theoretical calculation,simulation and experimental results further indicate that N,P,Mn multi-doping effectively improves the superior lithiophilicity of Li-Mn@NPC-CC,which induces uniform Li deposition/dissolution to suppress dendrite growth over cycles.Moreover,conductive and porous NPC matrix not only effectively improves the stability of Li-Mn@NPC-CC,but also provides abundant spaces to accelerate the transfer of ion/electron and buffer electrode dimension variation during cycling.Hence,Li-Mn@NPC-CC-based symmetric cells exhibit extra-long cycling life (over 2200 h) with small hysteresis of 20 mV.When the LiMn@NPC-CC anode couples with air,Li iron phosphate (LiFePO_(4)),or hard carbon (C) cathode,the assembled full cells exhibit outstanding performance with low hysteresis and stable cycling properties.Especially,the corresponding pouch-typed Li–air cells also exhibit good performance at different bending angles and even power a series of electronic devices.
基金supported by Solar Energy Research Initiative(SERI)of Department of Science and Technology(DST),Govt.of India
文摘In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanofibers were characterized by dynamic light scattering（DLS）, UV–Vis spectroscopy,photoluminescence（PL） spectra, X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The SnOnanofibers deposited on fluorine-doped tin oxide（SnO） and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum（Pt） counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage（Voc）of 0.80 V, and a photocurrent density（JSC） of 3.70 m A/cmwere obtained for cells with SnOthickness of5–6 μm and cell area of 0.25 cmunder standard 1 Sun illumination（100 m W/cm）. The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.
文摘SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers are characterized by using field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),x-ray diffraction(XRD),and x-ray photoelectron spectrometer(XPS).The analyses of SnO_(2)/Co_(3)O_(4)NFs by EDS and HRTEM show that the cobalt and tin exist on one nanofiber,which is related to the homopolar electrospinning and the crystallization during sintering.As a typical n-type semiconductor,Sn O_(2)has the disadvantages of high optimal operating temperature and poor reproducibility.Comparing with Sn O_(2),the optimal operating temperature of SnO_(2)/Co_(3)O_(4)NFs is reduced from 350℃to 250℃,which may be related to the catalysis of Co_(2)O_(2).The response of SnO_(2)/Co_(3)O_(4)to 100-ppm ethanol at 250℃is 50.9,9 times higher than that of pure Sn O_(2),which may be attributed to the p–n heterojunction between the n-type Sn O_(2)crystalline grain and the p-type Co_(2)O_(2)crystalline grain.The nanoscale p–n heterojunction promotes the electron migration and forms an interface barrier.The synergy effects between Sn O_(2)and Co_(2)O_(2),the crystalline grain p–n heterojunction,the existence of nanofibers and the large specific surface area all jointly contribute to the improved gas sensing performance.
文摘Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.
