The research and exploration of manganese-based aqueous zinc-ion batteries have been controversial of cycle stability and mechanism investigation,thus improving the stability and exploring storage mechanism are still ...The research and exploration of manganese-based aqueous zinc-ion batteries have been controversial of cycle stability and mechanism investigation,thus improving the stability and exploring storage mechanism are still the most main issue.Defect engineering has become an effective method to improve cycle stability.Herein,a nitrogen-doped ε-MnO_(2)(MnO_(2)@N)has been prepared using electrochemical deposition and heat treatment under nitrogen atmosphere.As the cathode for zinc-ion batteries,the capacity retention rate of MnO_(2)@N cathode is close to 100%after 500 cycles at 0.5 A g^(-1),while the capacity retention rate for the initial MnO_(2) cathode is 62%.At 5 A g^(-1),the capacity retention rate of MnO_(2)@N cathode is 83%after 1000 cycles,which is much higher than the 27%capacity retention rate for the original MnO_(2) cathode.And it can be found that the oxygen vacancies increase after nitrogen doping,which can improve the conductivity of the MnO_(2)@N cathode.Also,there is Mn-N bond in MnO_(2)@N,which can enhance the electrochemical stability of MnO_(2)@N cathode.In addition,the electrochemical mechanism of MnO_(2)@N cathode has been explored by the CV,GCD and GITT tests.It is found that nitrogen doping promotes the intercalation of H^(+) and the corresponding capacity contribution.Compared with the original MnO_(2) cathode,the diffusion coefficient of H^(+) and Zn^(2+) in MnO_(2)@N cathode increases.Also,the reactions during the charging and discharging process are explored through the ex-situ XRD test.And this work may provide some new ideas for improving the stability of manganese-based zinc-ion batteries.展开更多
The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li...The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li-S batteries.Herein,the multi-dimensional composite frame has been proposed as the modified separator(MCCoS/PP)of Li-S battery,which is composed of CoS_(2) nanoparticles on alkali-treated MXene nanosheets and carbon nanotubes.Both experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP separator.It can not only promote the liquid-solid conversion in the reduction process,but also accelerate the decomposition of insoluble Li_(2)S in the oxidation process.In addition,LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference numbers.Simultaneously,the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances,which is also beneficial to the rate performance and cycling stability.The Li-S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g^(−1) at 20C,and the capacity decay per cycle is only 0.033%in 1000 cycles at 7C.Also,high area capacity(6.34 mAh cm^(−2))with a high sulfur loading(7.7 mg cm^(−2))and a low electrolyte/sulfur ratio(7.5μL mg^(−1))is achieved.展开更多
Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction...Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction with the reaction kinetics processes regulated to rapidly synthesize Au-Ag hollow alloy nanoparticles with tunable cavity sizes.The position of the localized surface plasmon resonance(LSPR)peak could be effectively adjusted between 490 nm and 713 nm by decreasing the cavity size of the Au-Ag hollow nanoparticles from 35 nm to 20 nm.The plasmon-enhanced photocatalytic H2 evolution of alloy nanoparticles with different cavity sizes was investigated.Compared with pure P25(TiO2),intact and thin-shelled Au-Ag hollow nanoparticles(HNPs)-supported photocatalyst exhibited an increase in the photocatalytic H2 evolution rate from 0.48μmol h^−1 to 4μmol h^−1 under full-spectrum irradiation.This improved photocatalytic performance was likely due to the plasmon-induced electromagnetic field effect,which caused strong photogenerated charge separation,rather than the generation of hot electrons.展开更多
The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays as...The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.展开更多
Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a cha...Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a challenging task to reduce the amount of Pt as well as ensure good catalytic performance.Herein,anchoring of Pt single atoms(0.21 wt‰)with ultra-low content on g-C_(3)N_(4)nanosheets(Pt_(0.21)/CN)has been successfully achieved.The obtained Pt_(0.21)/CN catalyst shows excellent two-electron oxygen reduction(2e-ORR)capability for hydrogen peroxide(H_(2)O_(2)).Compared with CN,its H_(2)O_(2)selectivity increased from 80%to 98%in 0.1M KOH,surpassing those in most of the reported studies.Besides,the H_(2)O_(2)production rate of Pt_(0.21)/CN is 767 mmol gcat^(-1)h-1,which is 11.1 times that of CN.This work may pave the way toward the development of an effective method for the design of noblemetal electrocatalysts with low metal loading and high catalytic activity.展开更多
It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2...It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2)S_(4)/N,S co-doped reduced graphene oxide(NCS/NS-rGO)electrocatalyst for water splitting,in which NCS microspheres are composed of one-dimentional(1D)nanorods grown homogeneously on the surface of NS-rGOs).The synergetic effect,abundant active sites,and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in both alkaline and neutral conditions.Furthermore,NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm^(2) with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition.These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.展开更多
Since 2020,some new breakthroughs in the field of MXene synthesis scheme such as water-free etching,HCl-based hydrothermal etching,halogen etching,and other novel synthesis methods have been proposed.Not only that,the...Since 2020,some new breakthroughs in the field of MXene synthesis scheme such as water-free etching,HCl-based hydrothermal etching,halogen etching,and other novel synthesis methods have been proposed.Not only that,the application of MXene in zinc-ion storage devices has also made great progress in the past 2 years.The understanding of zinc-ion storage mechanism of MXene has undergone profound changes,and its applications have also become diversified,demonstrating the great potential of MXene for high performance zinc-ion storage devices.In this review,we have summarized the preparation and synthesis of MXene materials and systematically investigated the progress of MXene in aqueous zinc-ion storage devices.In particular,for the synthesis of MXene,we added recent reports of conventional synthesis schemes that have been widely reported to help understand their development and combined with recent novel synthesis schemes to provide a distinct partition framework.In addition,for the application of MXene,we discussed the cognitive change of zinc-ion storage mechanism of MXene and conducted an in-depth discussion about the design philosophy of MXene and their characteristics.Finally,a comprehensive perspective on the future development of MXene in the synthetic strategy and aqueous zinc-ion storage applications have been outlined.展开更多
Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are generally catalyzed by precious metals(Pt)and metal oxides(IrO_(2))which still have many shortages including expensive price,poor selectivity and und...Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are generally catalyzed by precious metals(Pt)and metal oxides(IrO_(2))which still have many shortages including expensive price,poor selectivity and undesirable stability.In this work,we report a Mn0-doped CoN_(x) on N-doped porous carbon(Mn-CoN_(x)/N-PC)composite from carbonizing metal-organic framework(MOF)derivative as the dual-functional catalyst to boost both the ORR and OER performances.Owing to the strong coordination effect between nitrogen and metal elements,the introduction of N can obviously improve the content of Co-N-C active sites for ORR.Meanwhile,the Mn-doping significantly regulates the electronic structure of the Co element and increases the content of Co^(0) which provide efficient OER active sites.Mn-CoN_(x)/N-PC catalyst delivers super dual-functional activity with a half-wave potential of 0.85 V,better than the 20%Pt/C catalyst(0.82 V).When used in Zn-air batteries for testing,Mn-CoN_(x)/N-PC electrocatalyst shows a high power density(145 mW·cm^(−2))and good cycle performance.展开更多
Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related...Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.展开更多
Light absorption plays an important role in improving the power conversion efficiency(PCE)of quantum dot-sensitized solar cells(QDSSCs).In this study,a multifunctional long-persistence phosphor(LPP)layer was introduce...Light absorption plays an important role in improving the power conversion efficiency(PCE)of quantum dot-sensitized solar cells(QDSSCs).In this study,a multifunctional long-persistence phosphor(LPP)layer was introduced into the CdS/CdSe QDSSCs via a simple doctor blade method.The LPP layer can simultaneously improve the light harvesting and photo charge transfer in CdS/CdSe QDSSCs.As a result,their short-circuit current and corresponding PCE are effectively enhanced.The PCE can reach up to 5.07%,which is about 24%larger than that of the conventional CdS/CdSe QDSSCs without LPP layer.The solar cells can work in dark for a while due to the long-lasting fluorescence of the LPP layer.This research provides an effective way to improve the PCE of QDSSCs,and finds the possibility for all-weather QDSSCs.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 61376011, 51402141, 61604086, 11975114)the Gansu Provincial Natural Science Foundation of China (No. 17JR5RA198)+1 种基金the Fundamental Research Funds for the Central Universities (No. lzujbky-2018-119, lzujbky-2018-ct08, lzujbky-2019-it23)the Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps (No. 2018AB004).
文摘The research and exploration of manganese-based aqueous zinc-ion batteries have been controversial of cycle stability and mechanism investigation,thus improving the stability and exploring storage mechanism are still the most main issue.Defect engineering has become an effective method to improve cycle stability.Herein,a nitrogen-doped ε-MnO_(2)(MnO_(2)@N)has been prepared using electrochemical deposition and heat treatment under nitrogen atmosphere.As the cathode for zinc-ion batteries,the capacity retention rate of MnO_(2)@N cathode is close to 100%after 500 cycles at 0.5 A g^(-1),while the capacity retention rate for the initial MnO_(2) cathode is 62%.At 5 A g^(-1),the capacity retention rate of MnO_(2)@N cathode is 83%after 1000 cycles,which is much higher than the 27%capacity retention rate for the original MnO_(2) cathode.And it can be found that the oxygen vacancies increase after nitrogen doping,which can improve the conductivity of the MnO_(2)@N cathode.Also,there is Mn-N bond in MnO_(2)@N,which can enhance the electrochemical stability of MnO_(2)@N cathode.In addition,the electrochemical mechanism of MnO_(2)@N cathode has been explored by the CV,GCD and GITT tests.It is found that nitrogen doping promotes the intercalation of H^(+) and the corresponding capacity contribution.Compared with the original MnO_(2) cathode,the diffusion coefficient of H^(+) and Zn^(2+) in MnO_(2)@N cathode increases.Also,the reactions during the charging and discharging process are explored through the ex-situ XRD test.And this work may provide some new ideas for improving the stability of manganese-based zinc-ion batteries.
基金This work was financially supported by the Gansu Provincial Natural Science Foundation of China(Nos.21JR7RA493,17JR5RA198,2020HZ-2,21JR7RA470)the Cooperation project of Gansu Academy of Sciences(2020HZ-2)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2018-119,lzujbky-2018-ct08,lzujbky-2019-it23)Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)Hubei University of Arts and Science(No.2020kypytd002)Xiangyang Science and Technology Research and Development(No.2020YL09).
文摘The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li-S batteries.Herein,the multi-dimensional composite frame has been proposed as the modified separator(MCCoS/PP)of Li-S battery,which is composed of CoS_(2) nanoparticles on alkali-treated MXene nanosheets and carbon nanotubes.Both experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP separator.It can not only promote the liquid-solid conversion in the reduction process,but also accelerate the decomposition of insoluble Li_(2)S in the oxidation process.In addition,LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference numbers.Simultaneously,the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances,which is also beneficial to the rate performance and cycling stability.The Li-S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g^(−1) at 20C,and the capacity decay per cycle is only 0.033%in 1000 cycles at 7C.Also,high area capacity(6.34 mAh cm^(−2))with a high sulfur loading(7.7 mg cm^(−2))and a low electrolyte/sulfur ratio(7.5μL mg^(−1))is achieved.
基金supported by the National Natural Science Foundation of China(No.61704114)the Key areas of Science and Technology Program of Xinjiang Production and Construction Corps,China(No.2018AB004)the National Science Foundation(CBET-1803256).
文摘Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction with the reaction kinetics processes regulated to rapidly synthesize Au-Ag hollow alloy nanoparticles with tunable cavity sizes.The position of the localized surface plasmon resonance(LSPR)peak could be effectively adjusted between 490 nm and 713 nm by decreasing the cavity size of the Au-Ag hollow nanoparticles from 35 nm to 20 nm.The plasmon-enhanced photocatalytic H2 evolution of alloy nanoparticles with different cavity sizes was investigated.Compared with pure P25(TiO2),intact and thin-shelled Au-Ag hollow nanoparticles(HNPs)-supported photocatalyst exhibited an increase in the photocatalytic H2 evolution rate from 0.48μmol h^−1 to 4μmol h^−1 under full-spectrum irradiation.This improved photocatalytic performance was likely due to the plasmon-induced electromagnetic field effect,which caused strong photogenerated charge separation,rather than the generation of hot electrons.
基金This work was supported by the Natural Science Foundation of China(51962032,61704114,and 51764049)the Youth Innovative Talents Cultivation Fund,Shihezi University(KX01480109)the Opening Project of The Research Center for Material Chemical Engineering Technology of Xinjiang Bingtuan(2017BTRC007).
文摘The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.
基金This work was financially supported by the Gansu Provincial Natural Science Foundation of China(Nos.21JR7RA493,17JR5RA198,2020HZ‐2,21JR7RA470)the Cooperation project of Gansu Academy of Sciences(2020HZ‐2)+6 种基金the Fundamental Research Funds for the Central Universities(Nos.lzujbky‐2018‐119,lzujbky‐2018‐ct08,lzujbky‐2019‐it23)Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)Hubei University of Arts and Science(No.2020kypytd002)Xiangyang Science and Technology Research and Development(No.2020YL09)the Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)All the DFT calculations were supported by the Supercomputing Center of Lanzhou UniversityAll SEM,TEM,and HAADFSTEM were supported by the Electron Microscopy Centre of Lanzhou University.
文摘Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a challenging task to reduce the amount of Pt as well as ensure good catalytic performance.Herein,anchoring of Pt single atoms(0.21 wt‰)with ultra-low content on g-C_(3)N_(4)nanosheets(Pt_(0.21)/CN)has been successfully achieved.The obtained Pt_(0.21)/CN catalyst shows excellent two-electron oxygen reduction(2e-ORR)capability for hydrogen peroxide(H_(2)O_(2)).Compared with CN,its H_(2)O_(2)selectivity increased from 80%to 98%in 0.1M KOH,surpassing those in most of the reported studies.Besides,the H_(2)O_(2)production rate of Pt_(0.21)/CN is 767 mmol gcat^(-1)h-1,which is 11.1 times that of CN.This work may pave the way toward the development of an effective method for the design of noblemetal electrocatalysts with low metal loading and high catalytic activity.
基金supported by the National Natural Science Foundation of China(Nos.51962032,61704114,and 51764049)the Youth Innovative Talents Cultivation Fund,Shihezi University(No.KX01480109)the Opening Project of The Research Center for Material Chemical Engineering Technology of Xinjiang Bingtuan(No.2017BTRC007).
文摘It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2)S_(4)/N,S co-doped reduced graphene oxide(NCS/NS-rGO)electrocatalyst for water splitting,in which NCS microspheres are composed of one-dimentional(1D)nanorods grown homogeneously on the surface of NS-rGOs).The synergetic effect,abundant active sites,and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in both alkaline and neutral conditions.Furthermore,NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm^(2) with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition.These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.
基金Gansu Provincial Natural Science Foundation of China,Grant/Award Numbers:17JR5RA198,2020HZ-2,21JR7RA470Cooperation project of Gansu Academy of Sciences,Grant/Award Number:2020HZ-2+3 种基金Fundamental Research Funds for the Central Universities,Grant/Award Numbers:lzujbky-2018-119,lzujbky-2018-ct08,lzujbky-2019-it23Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps,Grant/Award Number:2018AB004Hubei University of Arts and Science,Grant/Award Number:2020kypytd002Xiangyang Science and Technology Research and Development,Grant/Award Number:2020YL09。
文摘Since 2020,some new breakthroughs in the field of MXene synthesis scheme such as water-free etching,HCl-based hydrothermal etching,halogen etching,and other novel synthesis methods have been proposed.Not only that,the application of MXene in zinc-ion storage devices has also made great progress in the past 2 years.The understanding of zinc-ion storage mechanism of MXene has undergone profound changes,and its applications have also become diversified,demonstrating the great potential of MXene for high performance zinc-ion storage devices.In this review,we have summarized the preparation and synthesis of MXene materials and systematically investigated the progress of MXene in aqueous zinc-ion storage devices.In particular,for the synthesis of MXene,we added recent reports of conventional synthesis schemes that have been widely reported to help understand their development and combined with recent novel synthesis schemes to provide a distinct partition framework.In addition,for the application of MXene,we discussed the cognitive change of zinc-ion storage mechanism of MXene and conducted an in-depth discussion about the design philosophy of MXene and their characteristics.Finally,a comprehensive perspective on the future development of MXene in the synthetic strategy and aqueous zinc-ion storage applications have been outlined.
基金the Gansu Provincial Natural Science Foundation of China(No.17JR5RA198)the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2018-119,lzujbky-2018-ct08,and lzujbky-2019-it23)+4 种基金Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)the National Natural Science Foundation of China(No.11975114)Cooperation project of Gansu Academy of Sciences(No.2020HZ-2)the fund of State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals(No.SKLAB02019001)Cooperation project of Gansu Academy of Sciences(No.2020HZ-2).
文摘Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are generally catalyzed by precious metals(Pt)and metal oxides(IrO_(2))which still have many shortages including expensive price,poor selectivity and undesirable stability.In this work,we report a Mn0-doped CoN_(x) on N-doped porous carbon(Mn-CoN_(x)/N-PC)composite from carbonizing metal-organic framework(MOF)derivative as the dual-functional catalyst to boost both the ORR and OER performances.Owing to the strong coordination effect between nitrogen and metal elements,the introduction of N can obviously improve the content of Co-N-C active sites for ORR.Meanwhile,the Mn-doping significantly regulates the electronic structure of the Co element and increases the content of Co^(0) which provide efficient OER active sites.Mn-CoN_(x)/N-PC catalyst delivers super dual-functional activity with a half-wave potential of 0.85 V,better than the 20%Pt/C catalyst(0.82 V).When used in Zn-air batteries for testing,Mn-CoN_(x)/N-PC electrocatalyst shows a high power density(145 mW·cm^(−2))and good cycle performance.
基金supported by the National Natural Science Foundation of China(61376011 and 51402141)Gansu Provincial Natural Science Foundation(17JR5RA198)+1 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2018-119 and lzujbky-2018-ct08)Shenzhen Science and Technology Innovation Committee(JCYJ20170818155813437)。
文摘Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.
基金financially supported by the National Natural Science Foundation of China (61376011, 51402141 and 61604086)Gansu Provincial Natural Science Foundation (17JR5RA198)+2 种基金the Fundamental Research Funds for the Central Universities (LZUJBKY-2018-119 and LZUJBKY-2018-CT08)Shenzhen Science and Technology Innovation Committee (JCYJ20170818155813437)the Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps (2018AB004)
文摘Light absorption plays an important role in improving the power conversion efficiency(PCE)of quantum dot-sensitized solar cells(QDSSCs).In this study,a multifunctional long-persistence phosphor(LPP)layer was introduced into the CdS/CdSe QDSSCs via a simple doctor blade method.The LPP layer can simultaneously improve the light harvesting and photo charge transfer in CdS/CdSe QDSSCs.As a result,their short-circuit current and corresponding PCE are effectively enhanced.The PCE can reach up to 5.07%,which is about 24%larger than that of the conventional CdS/CdSe QDSSCs without LPP layer.The solar cells can work in dark for a while due to the long-lasting fluorescence of the LPP layer.This research provides an effective way to improve the PCE of QDSSCs,and finds the possibility for all-weather QDSSCs.
