High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm...High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm,the dual-Schottky-junctions coupling device(DSCD)was fabricated.Due to the electrically floating Ga_(2)O_(3)nanobelt region coupling with the double Schottky-junctions,the current I_(S2)increases firstly and rapidly reaches into saturation as increase the voltage V_(S2).The saturation current is about 10 pA,which is two orders of magnitude lower than that of a single Schottky-junction.In the case of solar-blind ultraviolet(UV)light irradiation,the photogenerated electrons further aggravate the coupling physical mechanism in device.I_(S2)increases as the intensity of UV light increases.Under the UV light of 1820μW/cm^(2),I_(S2)quickly enters the saturation state.At V_(S2)=10 V,photo-to-dark current ratio(PDCR)of the device reaches more than 104,the external quantum efficiency(EQE)is 1.6×10^(3)%,and the detectivity(D*)is 7.5×10^(12)Jones.In addition,the device has a very short rise and decay times of 25−54 ms under different positive and negative bias.DSCD shows unique electrical and optical control characteristics,which will open a new way for the application of nanobelt-based devices.展开更多
The practical application of lithium–sulfur(Li–S)batteries is inhibited by the shuttle effect of lithium polysulfides(LiPSs)and slow polysulfide redox kinetics on the S cathode as well as the uncontrollable growth o...The practical application of lithium–sulfur(Li–S)batteries is inhibited by the shuttle effect of lithium polysulfides(LiPSs)and slow polysulfide redox kinetics on the S cathode as well as the uncontrollable growth of dendrites on the Li metal anode.Therefore,both cathode and anode sides must be considered when modifying LiS batteries.Herein,two-dimensional(2D)ultrathin CoSe_(2)nanobelts are in situ grown on 2D N-doped MXene nanosheets(CoSe_(2)@N-MXene)via one-step solvothermal process for the first time.Owing to its unique 2D/2D structure,CoSe_(2)@N-MXene can be processed to crumpled nanosheets by freeze-drying and flexible and freestanding films by vacuum filtration.These crumpled CoSe_(2)@NMXene nanosheets with abundant active sites and inner spaces can act as S hosts to accelerate polysulfide redox kinetics and suppress the shuttle effect of LiPSs owing to their strong adsorption ability and catalytic conversion effect with LiPSs.Meanwhile,the CoSe_(2)@N-MXene film(CoSe_(2)@NMF)can act as a current collector to promote uniform Li deposition because it contains lithiophilic CoSe_(2)and N sites.Under the systematic effect of CoSe_(2)@N-MXene on S cathode and Li metal anode,the electrochemical and safety performance of Li–S batteries are improved.CoSe_(2)@NMF also shows excellent storage performances in flexible energy storage devices.展开更多
As anode materials for high-performance sodium-ion batteries and potassium-ion batteries,bimetallic selenides have attracted great concern due to their relatively high electrical conductivity and electrochemical activ...As anode materials for high-performance sodium-ion batteries and potassium-ion batteries,bimetallic selenides have attracted great concern due to their relatively high electrical conductivity and electrochemical activity.However,the formidable challenge in the reaction process is the large volume change,leading to the structural collapse of material,and eventually the decline in electrochemical performance.Herein,a composite of hierarchical CoSe_(2)–MoSe_(2) tubes anchored on reduced graphene oxide nanosheets(CoSe_(2)–MoSe_(2)/rGO)is designed by an in situ hydrothermal selenization treatment.Benefiting from the synergistic effects between CoSe_(2) and MoSe_(2),unique hierarchical structure,and effective reduced graphene oxide coating,the CoSe_(2)–MoSe_(2)/rGO exhibited improved reaction kinetics and structural stability,and thus good electrochemical properties.A combination mechanism of intercalation and conversion of CoSe_(2)–MoSe_(2)/rGO by forming NaxCoSe_(2) and Mo_(15)Se_(19) as intermediate states is put forward on the basis of in situ and ex situ XRD analyses.展开更多
Porous α-Fe2O3 nanobelts have been prepared via a solvothermal route and subsequent calcination. The as-prepared nanostructure was characterized by XRD, FESEM, TEM, N2 adsorption-desorption isotherms, etc. The α-Fe2...Porous α-Fe2O3 nanobelts have been prepared via a solvothermal route and subsequent calcination. The as-prepared nanostructure was characterized by XRD, FESEM, TEM, N2 adsorption-desorption isotherms, etc. The α-Fe2O3 nanobelts presented obvious porous structures with the length of ca. 1~2μm, width of ca. 200~350 nm and thickness of ca. 30~60 nm. It was found that the assistance of inorganic additives played an important role in the shape control of α-Fe2O3 nanostructure. The gas-sensing performance of the fabricated sensor based on α-Fe2O3 nanobelts sample was also investigated, and the response towards 1000 ppm acetone can reach 24.4. In addition, the gas-sensing conductive mechanism of the sensor was also proposed.展开更多
Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifun...Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifunctional electrode fabricated by in situ growth of Mn-doped CoSe_(2)nanonetworks on carbon fiber cloth(Mn-CoSe_(2)/CFC),which shows attractive electrocatalytic properties toward glycerol oxidation reaction(GOR)in alkali and hydrogen evolution reaction(HER)in acid.A flow alkali/acid hybrid electrolytic cell(fA/A-hEC)was then developed by coupling anodic GOR with cathodic HER with the Mn-CoSe_(2)/CFC bifunctional electrode.Such fA/A-hEC enables a rather low voltage of 0.54 V to achieve 10 mA cm^(-2),and maintain long-term electrolysis stability over 300-h operation at 100 mA cm^(-2)with Faraday efficiencies of over 99%for H_(2)and 90%for formate production.The designed bifunctional electrode in such innovative fA/A-hEC device provides insightful guidance for coupling energy-efficient hydrogen production with biomass upgradation.展开更多
A facile preparation of ZnO nanobelts by chemical precipitation technique and its utility as catalyst in Knoevenagel condensation of 2,4-thiazolidinedione/rhodanine has been described. X-ray diffraction and transmissi...A facile preparation of ZnO nanobelts by chemical precipitation technique and its utility as catalyst in Knoevenagel condensation of 2,4-thiazolidinedione/rhodanine has been described. X-ray diffraction and transmission electron microscopy techniques revealed the formation ZnO nanobelts. Scanning electron microscopic observations indicate that the lengths of nanobelts are ranging from a few hundreds of micrometers to a few millimeters. Its use for the condensation of aldehydes and active methylene compounds under solvent free reaction condition at 90℃ afforded the corresponding products in excellent yields in minute time.展开更多
Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by...Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.展开更多
Vanadium oxide hydrate V3O7..H2O (H2V3O8) nanobelts have been synthesized by hydrothermal approach using V2O5 as vanadium source and phenolphthalein as structure-directing agent. Techniques X-ray powder diffraction (X...Vanadium oxide hydrate V3O7..H2O (H2V3O8) nanobelts have been synthesized by hydrothermal approach using V2O5 as vanadium source and phenolphthalein as structure-directing agent. Techniques X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy and nitrogen adsorption/desorption isotherms have been used to characterize the structure, morphology and composition of the nanobelts. The V3O7. H2O nanobelts are up to several hundreds of nanometers, the widths and thicknesses are 90 and 40 nm, respectively. The electroactivity of the nanobelts has been investigated. The as-synthesized material is promising for chemical and energy-related applications such as catalysts, electrochemical device and it may be applied in rechargeable lithium-ion batteries.展开更多
基金supported by Natural Science Basic Research Program in Shaanxi Province of China(No.2023-JCYB-574)National Natural Science Foundation of China(No.62204203).
文摘High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm,the dual-Schottky-junctions coupling device(DSCD)was fabricated.Due to the electrically floating Ga_(2)O_(3)nanobelt region coupling with the double Schottky-junctions,the current I_(S2)increases firstly and rapidly reaches into saturation as increase the voltage V_(S2).The saturation current is about 10 pA,which is two orders of magnitude lower than that of a single Schottky-junction.In the case of solar-blind ultraviolet(UV)light irradiation,the photogenerated electrons further aggravate the coupling physical mechanism in device.I_(S2)increases as the intensity of UV light increases.Under the UV light of 1820μW/cm^(2),I_(S2)quickly enters the saturation state.At V_(S2)=10 V,photo-to-dark current ratio(PDCR)of the device reaches more than 104,the external quantum efficiency(EQE)is 1.6×10^(3)%,and the detectivity(D*)is 7.5×10^(12)Jones.In addition,the device has a very short rise and decay times of 25−54 ms under different positive and negative bias.DSCD shows unique electrical and optical control characteristics,which will open a new way for the application of nanobelt-based devices.
基金supported by the National Natural Science Foundation of China(U21A2077 and 51972198)the Natural Science Foundation of Shandong Province(ZR2021ZD05,ZR2020JQ19,and ZR2023QB169)+3 种基金Taishan Scholars Program of Shandong Province(ts20190908 and tsqn201812002)the State Key Program of National Natural Science of China(62133007)Shenzhen Fundamental Research Program(JCYJ20190807093405503)China Postdoctoral Science Foundation(2022M721913).
文摘The practical application of lithium–sulfur(Li–S)batteries is inhibited by the shuttle effect of lithium polysulfides(LiPSs)and slow polysulfide redox kinetics on the S cathode as well as the uncontrollable growth of dendrites on the Li metal anode.Therefore,both cathode and anode sides must be considered when modifying LiS batteries.Herein,two-dimensional(2D)ultrathin CoSe_(2)nanobelts are in situ grown on 2D N-doped MXene nanosheets(CoSe_(2)@N-MXene)via one-step solvothermal process for the first time.Owing to its unique 2D/2D structure,CoSe_(2)@N-MXene can be processed to crumpled nanosheets by freeze-drying and flexible and freestanding films by vacuum filtration.These crumpled CoSe_(2)@NMXene nanosheets with abundant active sites and inner spaces can act as S hosts to accelerate polysulfide redox kinetics and suppress the shuttle effect of LiPSs owing to their strong adsorption ability and catalytic conversion effect with LiPSs.Meanwhile,the CoSe_(2)@N-MXene film(CoSe_(2)@NMF)can act as a current collector to promote uniform Li deposition because it contains lithiophilic CoSe_(2)and N sites.Under the systematic effect of CoSe_(2)@N-MXene on S cathode and Li metal anode,the electrochemical and safety performance of Li–S batteries are improved.CoSe_(2)@NMF also shows excellent storage performances in flexible energy storage devices.
基金supported by the National Natural Science Foundation of China(Grant No.21701144)。
文摘As anode materials for high-performance sodium-ion batteries and potassium-ion batteries,bimetallic selenides have attracted great concern due to their relatively high electrical conductivity and electrochemical activity.However,the formidable challenge in the reaction process is the large volume change,leading to the structural collapse of material,and eventually the decline in electrochemical performance.Herein,a composite of hierarchical CoSe_(2)–MoSe_(2) tubes anchored on reduced graphene oxide nanosheets(CoSe_(2)–MoSe_(2)/rGO)is designed by an in situ hydrothermal selenization treatment.Benefiting from the synergistic effects between CoSe_(2) and MoSe_(2),unique hierarchical structure,and effective reduced graphene oxide coating,the CoSe_(2)–MoSe_(2)/rGO exhibited improved reaction kinetics and structural stability,and thus good electrochemical properties.A combination mechanism of intercalation and conversion of CoSe_(2)–MoSe_(2)/rGO by forming NaxCoSe_(2) and Mo_(15)Se_(19) as intermediate states is put forward on the basis of in situ and ex situ XRD analyses.
基金supported by the Natural Science Foundation of Fujian Province(No.2017J05021)the National Natural Science Foundation of China(No.21201035)Fuzhou university undergraduate research training program in chemistry(HX2018-14)
文摘Porous α-Fe2O3 nanobelts have been prepared via a solvothermal route and subsequent calcination. The as-prepared nanostructure was characterized by XRD, FESEM, TEM, N2 adsorption-desorption isotherms, etc. The α-Fe2O3 nanobelts presented obvious porous structures with the length of ca. 1~2μm, width of ca. 200~350 nm and thickness of ca. 30~60 nm. It was found that the assistance of inorganic additives played an important role in the shape control of α-Fe2O3 nanostructure. The gas-sensing performance of the fabricated sensor based on α-Fe2O3 nanobelts sample was also investigated, and the response towards 1000 ppm acetone can reach 24.4. In addition, the gas-sensing conductive mechanism of the sensor was also proposed.
基金supported by the National Natural Science Foundation of China(Project No.21875253)the CAS Commonwealth Scientific and Industrial Research Organization(CSIRO)Joint Research Projects(121835KYSB20200039)+3 种基金the Scientific Research and Equipment Development Project of CAS(YJKYYQ20190007)Fujian Natural Science Foundation(2021J01210293)the Fujian Science and Technology Pilot Project(Project No.2020H0039)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Grant.YLUDNL Fund 2021011)。
文摘Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifunctional electrode fabricated by in situ growth of Mn-doped CoSe_(2)nanonetworks on carbon fiber cloth(Mn-CoSe_(2)/CFC),which shows attractive electrocatalytic properties toward glycerol oxidation reaction(GOR)in alkali and hydrogen evolution reaction(HER)in acid.A flow alkali/acid hybrid electrolytic cell(fA/A-hEC)was then developed by coupling anodic GOR with cathodic HER with the Mn-CoSe_(2)/CFC bifunctional electrode.Such fA/A-hEC enables a rather low voltage of 0.54 V to achieve 10 mA cm^(-2),and maintain long-term electrolysis stability over 300-h operation at 100 mA cm^(-2)with Faraday efficiencies of over 99%for H_(2)and 90%for formate production.The designed bifunctional electrode in such innovative fA/A-hEC device provides insightful guidance for coupling energy-efficient hydrogen production with biomass upgradation.
文摘A facile preparation of ZnO nanobelts by chemical precipitation technique and its utility as catalyst in Knoevenagel condensation of 2,4-thiazolidinedione/rhodanine has been described. X-ray diffraction and transmission electron microscopy techniques revealed the formation ZnO nanobelts. Scanning electron microscopic observations indicate that the lengths of nanobelts are ranging from a few hundreds of micrometers to a few millimeters. Its use for the condensation of aldehydes and active methylene compounds under solvent free reaction condition at 90℃ afforded the corresponding products in excellent yields in minute time.
基金supported by the National Natural Science Foundation of China(52072118,51772089)the Youth 1000 Talent Program of China+3 种基金the Research and Development Plan of Key Areas in Hunan Province(2019GK2235)the Key Research and Development Program of Ningxia(2020BDE03007)the China Postdoctoral Science Foundation(2019M653649)the Guangdong Basic and Applied Basic Research Fund(2019A1515110518,2019A1515111188,2020B0909030004)。
文摘Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.
文摘Vanadium oxide hydrate V3O7..H2O (H2V3O8) nanobelts have been synthesized by hydrothermal approach using V2O5 as vanadium source and phenolphthalein as structure-directing agent. Techniques X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy and nitrogen adsorption/desorption isotherms have been used to characterize the structure, morphology and composition of the nanobelts. The V3O7. H2O nanobelts are up to several hundreds of nanometers, the widths and thicknesses are 90 and 40 nm, respectively. The electroactivity of the nanobelts has been investigated. The as-synthesized material is promising for chemical and energy-related applications such as catalysts, electrochemical device and it may be applied in rechargeable lithium-ion batteries.
