基于CoSE(cloud of secure elements)概念,提出一个NFC安全支付协议。根据CoSE架构部署一个可信云支付平台,使用虚拟SE替代硬件安全模块,所有交易项都由云支付平台完成;商户的POS终端充当消费者和云支付平台的通信桥梁,消费者的NFC设备...基于CoSE(cloud of secure elements)概念,提出一个NFC安全支付协议。根据CoSE架构部署一个可信云支付平台,使用虚拟SE替代硬件安全模块,所有交易项都由云支付平台完成;商户的POS终端充当消费者和云支付平台的通信桥梁,消费者的NFC设备和商户的POS终端通过射频场连接,消费者NFC设备不需要数据网络即可完成支付流程;交易过程中通过对交易双方身份信息与随机数进行hash运算,实现正常交易匿名性。通过安全性分析及实验验证了该协议的正确性和安全性。展开更多
One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios.In this work,one-dimensional CoSe@N-doped carbon na...One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios.In this work,one-dimensional CoSe@N-doped carbon nanofibers(CoSe@NCNFs)are successfully by combining the techniques of electrospinning and annealing.Selenium powder are directly dispersed in the polyacrylonitrile/N,N-Dimethylformamide(DMF)solution containing cobalt salt to form the product.The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures.The Co Se@NC nanofibers annealed at 550℃(CoSe@NC-550)and displayed excellent storage properties,affording a high capacity of 796 m Ah·g-1at a current density of 1 A·g^-1 for 100 cycles.Moreover,it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8%at the scan rate of 1 mV/s through the cyclic voltammetry analysis.展开更多
Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and ...Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved.Herein,dimensional gradient structure of sheet-tube-dots is constructed with CoSe2@CNTs-MXene.Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte.For half-cell,CoSe2@CNTs-MXene exhibits high initial coulomb efficiency(81.7%)and excellent cycling performance(400 mAh g^-1 cycling for 200 times in 2 Ag^−1).Phase transformation pathway from crystalline CoSe2-Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction.Density functional theory study discloses the CoSe2@CNTs-MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak interaction between electrolyte and electrode interface.For full cell,CoSe2@CNTs-MXene//Na3V2(PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g^−1 over 50 cycles.Concisely,profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs-MXene hold great application potential for stable sodium storage.展开更多
Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of th...Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe_2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand(EDTA)-assisted hydrothermal process. The flower-like CoSe_2 nanorods show the brilliant electrochemical HER performance with 100 mA cm^(-2) at overpotential of 273 m V, a small Tafel slope of 35 mV dec^(-1) and strong durability in acid solution. The sparkly HER catalytic activity of CoSe_2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.展开更多
Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/...Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/Mo_(2)CT_(x))to enhance the hydrogen evolution reaction(HER)and supercapacitor activities via an ionic liquid-mediated method.Se vacancy pairs and heteroatom doping enable the reallocation of local electron states and add active sites,improving the electrochemical activity of NBF-CoSe/Mo_(2)CT_(x) with high HER activities over a broad range of pH.At a current density of 10 mA cm^(-2),overvoltages of 70 and 81 mV are respectively produced in 0.5 M H_(2)SO_(4)and 1 M KOH.The optimal structure also exhibits outstanding electrochemical performance in an asymmetric supercapacitor with an energy density of 34.2 Wh kg^(-1)at a power density of 15989.6Wkg^(-1).This study opens new avenues for the introduction of Se vacancies and heteroatom doping to improve the application performance.展开更多
Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed...Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe_(2) nanocrystals on 3D Se/N co-doped carbon networks(CoSe_(2)@3DSNC).The phase transition from Co to CoSe_(2) and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration,in which the CoSe_(2) nanocrystals are anchored on interlayer expanded carbon networks.Such unique configuration endows electrode with lower Na+diffusion energy barrier,higher Na+storage capability and better structural durability.Reflected in SIBs,the optimized CoSe_(2)@3 DSNC delivers superior rate capability(310 m Ah g^(-1) at 10 A g^(-1))and excellent longterm cycling stability(409 m Ah g^(-1) after 1200 cycles at 5 A g^(-1)).Moreover,this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.展开更多
Hierarchical porous carbon co-doped with heterogeneous atoms has attracted much attention thanks to sizable internal void space accommodating electrolyte,high-density microporous structure physically con-fining polysu...Hierarchical porous carbon co-doped with heterogeneous atoms has attracted much attention thanks to sizable internal void space accommodating electrolyte,high-density microporous structure physically con-fining polysulfides(LPS),and heterogeneous atoms serving as active sites to capture LPS.However,solely relying on carbon material defects to capture LPS proves ineffective.Hence,metal compounds must be introduced to chemisorb LPS.Herein,cobalt ions are in-situ grown on the polydopamine layer coated on the surface of biomass-derived S,N,P co-doped hierarchical porous carbon(SNP-PC).Then a layer of nitrogen-doped porous carbon(MPC)dotted with CoSe nanoparticles is acquired by selenizing.Thus,a strong-polar/weak-polar composite material of SNP-PC studded with CoSe nanoparticles is obtained(SNP-PC@MPC@CoSe).Button cells assembled with SNP-PC@MPC@CoSe-modified separator enable superb long-cycle stability and satisfactory rate performance.An excellent rate capacity of 796 mAh g^(−1)at a high current rate of 4 C with an ultra-low capacity fading of 0.06%over 700 cycles can be acquired.More impressively,even in a harsh test condition of 5.65 mg cm^(−2)sulfur loading and 4μL mg^(−1)ratio of electrolyte to active materials,the battery can still display a specific capacity of 980 mAh g^(−1)(area capacity of∼5.54 mAh cm^(−2))at 0.1 C.This work provides a promising route toward high-performance Li-S batteries.展开更多
The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to dri...The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.展开更多
Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is succe...Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is successfully transformed into CoSe2 embedded in N-doped carb on nano cage(CoSe2/N-C)via a growth-carbonization-selenization process.The carb on cloth supported CoSe2/N-C,as photocathode of DSC,demonstrates a good long-term stability and high photovoltaic efficiency(8.40%),outperforming Pt.The good efficiency can be attributed to the high catalytic activity of CoSe2,fast mass tran sfer of porous three-dimensi on al(3D)structure,and good electr on transport derived from the intimate con tact between CoSe2 and highly conductive carb on cloth.The high stability would be ascribed to N-doped carbon coating that perfectly prevents CoSe2 from decomposition.This work will pave the way to develop highly efficient and stable Pt-free photocathode for DSC.展开更多
Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb fa...Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.展开更多
文摘基于CoSE(cloud of secure elements)概念,提出一个NFC安全支付协议。根据CoSE架构部署一个可信云支付平台,使用虚拟SE替代硬件安全模块,所有交易项都由云支付平台完成;商户的POS终端充当消费者和云支付平台的通信桥梁,消费者的NFC设备和商户的POS终端通过射频场连接,消费者NFC设备不需要数据网络即可完成支付流程;交易过程中通过对交易双方身份信息与随机数进行hash运算,实现正常交易匿名性。通过安全性分析及实验验证了该协议的正确性和安全性。
基金supported by the National Natural Science Foundation of China (Grant No. 51302079)the Natural Science Foundation of Hunan Province (Grant No. 2017JJ1008)
文摘One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios.In this work,one-dimensional CoSe@N-doped carbon nanofibers(CoSe@NCNFs)are successfully by combining the techniques of electrospinning and annealing.Selenium powder are directly dispersed in the polyacrylonitrile/N,N-Dimethylformamide(DMF)solution containing cobalt salt to form the product.The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures.The Co Se@NC nanofibers annealed at 550℃(CoSe@NC-550)and displayed excellent storage properties,affording a high capacity of 796 m Ah·g-1at a current density of 1 A·g^-1 for 100 cycles.Moreover,it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8%at the scan rate of 1 mV/s through the cyclic voltammetry analysis.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U1632151 and 21706048)the Key Research and Development Project of Anhui Province of China(Grant No.1704a0902023)the Open Project of Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices(No.JS1802)。
文摘Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved.Herein,dimensional gradient structure of sheet-tube-dots is constructed with CoSe2@CNTs-MXene.Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte.For half-cell,CoSe2@CNTs-MXene exhibits high initial coulomb efficiency(81.7%)and excellent cycling performance(400 mAh g^-1 cycling for 200 times in 2 Ag^−1).Phase transformation pathway from crystalline CoSe2-Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction.Density functional theory study discloses the CoSe2@CNTs-MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak interaction between electrolyte and electrode interface.For full cell,CoSe2@CNTs-MXene//Na3V2(PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g^−1 over 50 cycles.Concisely,profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs-MXene hold great application potential for stable sodium storage.
基金financially supported by the National Natural Science Foundation of China (No. 21675131, 21273174)the Municipal Science Foundation of Chongqing City (No. CSTC2015jcyjB50001)
文摘Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe_2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand(EDTA)-assisted hydrothermal process. The flower-like CoSe_2 nanorods show the brilliant electrochemical HER performance with 100 mA cm^(-2) at overpotential of 273 m V, a small Tafel slope of 35 mV dec^(-1) and strong durability in acid solution. The sparkly HER catalytic activity of CoSe_2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.
基金supported by the National Natural Science Foundation of China(21905069)the Shenzhen Science and Technology Innovation Committee(JCYJ20180507183907224 and KQTD20170809110344233)the Economic,Trade and Information Commission of Shenzhen Municipality through the Graphene Manufacture Innovation Center(201901161514)。
文摘Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/Mo_(2)CT_(x))to enhance the hydrogen evolution reaction(HER)and supercapacitor activities via an ionic liquid-mediated method.Se vacancy pairs and heteroatom doping enable the reallocation of local electron states and add active sites,improving the electrochemical activity of NBF-CoSe/Mo_(2)CT_(x) with high HER activities over a broad range of pH.At a current density of 10 mA cm^(-2),overvoltages of 70 and 81 mV are respectively produced in 0.5 M H_(2)SO_(4)and 1 M KOH.The optimal structure also exhibits outstanding electrochemical performance in an asymmetric supercapacitor with an energy density of 34.2 Wh kg^(-1)at a power density of 15989.6Wkg^(-1).This study opens new avenues for the introduction of Se vacancies and heteroatom doping to improve the application performance.
基金financially supported by the National Natural Science Foundation of China(21471040)。
文摘Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe_(2) nanocrystals on 3D Se/N co-doped carbon networks(CoSe_(2)@3DSNC).The phase transition from Co to CoSe_(2) and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration,in which the CoSe_(2) nanocrystals are anchored on interlayer expanded carbon networks.Such unique configuration endows electrode with lower Na+diffusion energy barrier,higher Na+storage capability and better structural durability.Reflected in SIBs,the optimized CoSe_(2)@3 DSNC delivers superior rate capability(310 m Ah g^(-1) at 10 A g^(-1))and excellent longterm cycling stability(409 m Ah g^(-1) after 1200 cycles at 5 A g^(-1)).Moreover,this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.
基金supported by the National Natural Science Foundation of China(No.52003110)the Natural Science Foundation of Jiangxi Province(Nos.20202ACB202002,20202ACB214002).
文摘Hierarchical porous carbon co-doped with heterogeneous atoms has attracted much attention thanks to sizable internal void space accommodating electrolyte,high-density microporous structure physically con-fining polysulfides(LPS),and heterogeneous atoms serving as active sites to capture LPS.However,solely relying on carbon material defects to capture LPS proves ineffective.Hence,metal compounds must be introduced to chemisorb LPS.Herein,cobalt ions are in-situ grown on the polydopamine layer coated on the surface of biomass-derived S,N,P co-doped hierarchical porous carbon(SNP-PC).Then a layer of nitrogen-doped porous carbon(MPC)dotted with CoSe nanoparticles is acquired by selenizing.Thus,a strong-polar/weak-polar composite material of SNP-PC studded with CoSe nanoparticles is obtained(SNP-PC@MPC@CoSe).Button cells assembled with SNP-PC@MPC@CoSe-modified separator enable superb long-cycle stability and satisfactory rate performance.An excellent rate capacity of 796 mAh g^(−1)at a high current rate of 4 C with an ultra-low capacity fading of 0.06%over 700 cycles can be acquired.More impressively,even in a harsh test condition of 5.65 mg cm^(−2)sulfur loading and 4μL mg^(−1)ratio of electrolyte to active materials,the battery can still display a specific capacity of 980 mAh g^(−1)(area capacity of∼5.54 mAh cm^(−2))at 0.1 C.This work provides a promising route toward high-performance Li-S batteries.
基金the financial support by the National Natural Science Foundation of China(No.21771137)the Key Project of Natural Science Foundation of Tianjin(No.18JCZDJC97200)+1 种基金the Training Project of Innovation Team of Colleges and Universities in Tianjin(No.TD13-5020)the start-up fund of Qilu University of Technology,Shandong Academy of Sciences。
文摘The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.
基金the National Natural Science Foundation of China(Nos.21725501,21771019,21475007 and 21675009)the Fundamental Research Funds for the Central Universities(Nos.buctrc201706,buctrc201815 and buctrc201812).
文摘Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is successfully transformed into CoSe2 embedded in N-doped carb on nano cage(CoSe2/N-C)via a growth-carbonization-selenization process.The carb on cloth supported CoSe2/N-C,as photocathode of DSC,demonstrates a good long-term stability and high photovoltaic efficiency(8.40%),outperforming Pt.The good efficiency can be attributed to the high catalytic activity of CoSe2,fast mass tran sfer of porous three-dimensi on al(3D)structure,and good electr on transport derived from the intimate con tact between CoSe2 and highly conductive carb on cloth.The high stability would be ascribed to N-doped carbon coating that perfectly prevents CoSe2 from decomposition.This work will pave the way to develop highly efficient and stable Pt-free photocathode for DSC.
基金This work is supported by the financial support of the Beijing Natural Science Foundation(No.2182013)classification development at Capital Normal University(No.2155091).
文摘Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.
