Cobalt selenide(CoSe_(2))has become a promising anode material for sodium-ion batteries(SIBs)due to its stable chemical properties,environmental friendliness,and high theoretical capacity.However,the undesirable rate ...Cobalt selenide(CoSe_(2))has become a promising anode material for sodium-ion batteries(SIBs)due to its stable chemical properties,environmental friendliness,and high theoretical capacity.However,the undesirable rate capacity and cycle stability of the anode materials largely limit its applications for SIBs due to the relatively low electronic conductivity and huge volume change during the Na+insertion/extraction.In this study,electrostatic spinning combined with a wet chemical method is employed to synthesize coral-like composite material(CNF@c-CoSe_(2)/C),which is composed of CoSe_(2)/carbon nanosheet arrays(CoSe_(2)/C)and carbon nanofibers(CNFs).CoSe_(2)/C nanoflakes derived from metal-organic frameworks(MOFs)with high surface area and the porous structure can inhibit the pulverization and amorphization of CoSe_(2) during charge and discharge processes,thus significantly keeping the stability of the microstructure.CNF can limit the overgrowth of nanosheets and serve as a conductive skeleton.Compared to two-dimensional CoSe_(2)/C nanoflakes and pure CoSe_(2) nanoparticles,the composite can expose more active sites and effectively accelerate the diffusion of Na+,which displays enhanced rate capability(266.5 mAh·g^(-1) at 5.0 A·g^(-1))and cycling stability(268.3 mAh·g^(-1) after 100 cycles at 1.0 A·g^(-1)).Moreover,the rational preparation strategy for metal selenide-based heterostructure material presents a new way for high-performance SIB s.展开更多
Developing bifunctional electrocatalysts with both high catalytic activity and high stability is crucial for efficient water splitting in alkaline media.Herein,a Fe-incorporated dual-metal selenide on nickel foam(Co_(...Developing bifunctional electrocatalysts with both high catalytic activity and high stability is crucial for efficient water splitting in alkaline media.Herein,a Fe-incorporated dual-metal selenide on nickel foam(Co_(0.9)Fe_(0.1)-Se/NF) is synthesized via a facile one-step electrodeposition method.As-synthesized materials could serve as self-supported bifunctional electrocatalysts with excellent catalytic activity towards oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in alkaline media.Experimental results show that delivering a 10 mA cm^(-2) water splitting current density only requires a cell voltage of 1.55 V.In addition,a very stable performance could be kept for about 36 hours,indicating their excellent working stability.Moreover,by means of phase analysis,we have identified that the evolution of the synthesized Co_(0.9)Fe_(0.1)-Se/NF experiences two entirely different processes in HER and OER,which hydroxide and oxyhydroxide are regarded as the real active sites,respectively.This work may pave the way to further understanding the relationships between the reactivity and stability of chalcogenide-based electrocatalysts and facilitating the rational design of efficient electrocatalysts for future renewable energy system applications.展开更多
In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state reaction.The method is applied to synthesize ...In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state reaction.The method is applied to synthesize an ultrafine CoSe2 nanocrystal@N-doped carbon matrix confined within HMCSs(denoted as CoSe2@NC/HMCS)for use as advanced anodes in highperformance potassium-ion batteries(KIBs).The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework(ZIF-67)within the HMCS templates under vacuum conditions and the subsequent selenization.Thermal treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any solvents.During the subsequent selenization process,the“dual confinement system”,composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS,can effectively suppress the overgrowth of CoSe2 nanocrystals.Thus,the resulting uniquely structured composite exhibits a stable cycling performance(442 mAh g^−1 at 0.1 A g^−1 after 120 cycles)and excellent rate capability(263 mAh g^−1 at 2.0 A g^−1)as the anode material for KIBs.展开更多
Lithium-sulfur battery(Li-S)is considered as one of the new-generation rechargeable batteries with high performance because of its extremely high theoretical capacity,energy density,environmental harmony and low cost....Lithium-sulfur battery(Li-S)is considered as one of the new-generation rechargeable batteries with high performance because of its extremely high theoretical capacity,energy density,environmental harmony and low cost.However,low electrical and ionic conductivity of sulfur,safety concerns and parasitic reaction generated by the dissolved polysulfide species in electrolyte hinder the commercialization of Li-S battery.Herein,we report a polyhedral porous structure comprising of carbon coating metal selenide nanoparticles(CoSe2/C),which could not only host sulfur for Li-S battery owing to its porous and conductive structure,but also mitigate the shuttle phenomenon by polysulfides adsorption and catalytic acceleration of redox kinetics.As a result,a performance enhanced CoSe2/C-S electrode for Li-S battery is achieved.展开更多
Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microsphere...Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte system.The microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume stress.Consequently,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life stability.For instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.展开更多
Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the ...Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the electron-enriched Pt induced by CoSe_(2)has an efficient bi-functional catalytic ability for alcohol fuels electro-reforming of hydrogen in acid electrolytes.The theoretical calculation revealed the advantages of electron-enriched Pt surface for the adsorption of intermediate,which is well supported by spectroscopic analysis and CO-stripping techniques.Largely improved catalytic performances of activity,durability,and kinetics are demonstrated compared to the conventional alloy system and commercial Pt/C catalyst,due to the efficient synergism of Pt and CoSe_(2);the peak current density of Pt/CoSe_(2)for methanol(ethanol)oxidation is 87.61(48.27)m A cm^(-2),which is about 3.3(2.0)times higher than that of Pt/C catalyst and 2.0(1.5)times that of the traditional PtCo alloy catalysts.Impressively,about 80%of the initial current was found after 1000 cycles of stability test for alcohol fuel oxidation of Pt/CoSe_(2)catalyst,higher than that of Pt/C(ca.50%)and PtCo catalyst(65%).When Pt/CoSe_(2)catalyst serviced as bi-functional catalysts for electrolyzer,a low cell potential of 0.65(0.78)V for methanol(ethanol)electrolysis was required to reach 10 m A cm^(-2),which was about 1030(900)m V less than that of conventional water electrolysis using Pt/C as the catalyst.The current result is instructive for the design of novel bifunctional catalyst and the understanding of hydrogen generation via alcohol fuel electro-reforming.展开更多
Cobalt selenide(CoSe_(2))has garnered considerable attention as a prospective anode candidate for advanced lithium-ion storage,prompting comprehensive investigations.However,CoSe_(2)-based anodes usually suffer from s...Cobalt selenide(CoSe_(2))has garnered considerable attention as a prospective anode candidate for advanced lithium-ion storage,prompting comprehensive investigations.However,CoSe_(2)-based anodes usually suffer from significant volume variation upon lithiation leading to unsatisfactory cycling stability.Herein,a versatile synthesis route is proposed for the in-situ fabrication of CoSe2nanoparticles embedded in N-dope carbon skeleton(CoSe_(2)@NC)through annealing treatment and selenization of a metal–organic framework-derived(MOF)precursor.The N-doped carbon derived from the MOF serves not only as an excellent conductive substrate but also as a confined reactor,effectively inhibiting the structural instability and alleviating the inevitable volume change of CoSe_(2).Owing to their unique nanostructure,the as-prepared CoSe_(2)@NC exhibits a high capacity of 745.9mAh·g^(-1)at 0.1 A·g^(-1),while maintaining excellent rate capability and an impressive lifespan.Furthermore,the assembled lithium-ion capacitor(LIC)based on CoSe_(2)@NC demonstrates an energy density of 130Wh·kg^(-1),a power density of 24.6 kW·kg^(-1),and remarkable capacity retention of 90.8%after 8000 cycles.These results highlight the great potential of CoSe_(2)@NC for practical applications.展开更多
Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe_(...Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe_(2)@NC@NCNFs bifunctional catalyst was designed and fabricated by confining cubic CoSe_(2)nanoparticles to three-dimensional(3D)porous MOFs-derived nitrogen-doped carbon(NC)and one-dimensional(1D)N-doped carbon nanofibers(NCNFs)through a facile encapsulate strategy.The 1D/3D continuous network structure contributes to the improvement of specific surface area and electronic conductivity,while the strong synergistic effect between CoSe_(2)sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion resistance.The as-constructed CoSe_(2)@NC@NCNFs catalyst exhibits high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V(vs.RHE)in ORR and a low overpotential of 280 mV at 10 mA·cm^(−2)in OER.More encouragingly,the rechargeable ZABs with CoSe_(2)@NC@NCNFs cathode deliver high peak power densities(126.8 mW·cm^(−2)),large specific capacities(763.1 mA·h·g^(−1)),and robust charge-discharge cycling stability over 240 cycles.This study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.展开更多
The development of high-performance non-precious metal-based robust bifunctional electrocatalyst for both hydrogen evolution reaction(HER) and oxygen evolution reactions(OER) in alkaline media is essential for the ele...The development of high-performance non-precious metal-based robust bifunctional electrocatalyst for both hydrogen evolution reaction(HER) and oxygen evolution reactions(OER) in alkaline media is essential for the electrochemical overall water splitting technologies. Herein, we demonstrate that the HER/OER performance of Co Se_(2)can be significantly enhanced by tuning the 3d-orbital electron filling degree through Mo doping. Both density functional theory(DFT) calculations and experimental results imply that the doping of Mo with higher proportion of the unoccupied d-orbital(P_(un)) could not only serve as the active center for water adsorption to enhance the water molecule activation, but also modulate the electronic structures of Co metal center leading to the optimized adsorption strength of*H. As expected, the obtained Mo-Co Se_(2)exhibits a remarkable bifunctional performance with overpotential of only 85 m V for HER and 245 m V for OER to achieve the current density of 10 m A/cm^(2)in alkaline media.This work will provide a valuable insight to design highly efficient bifunctional electrocatalyst towards HER and OER.展开更多
The development of efficient, low-cost, for water splitting, particularly those stable, non-noble-metal electrocatalysts that can catalyze both the hydrogen evolution reaction (HER) at the cathode and oxygen evoluti...The development of efficient, low-cost, for water splitting, particularly those stable, non-noble-metal electrocatalysts that can catalyze both the hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode, is a challenge. We have developed a facile method for synthesizing CoSe2 nanoparticles uniformly anchored on carbon fiber paper (CoSe2/CF) via pyrolysis and selenization of in situ grown zeolitic imidazolate framework-67 (ZIF-67). CoSe2/CF shows high and stable catalytic activity in both the HER and OER in alkaline solution. At a low cell potential, i.e., 1.63 V, a water electrolyzer equipped with two CoSe2/CF electrodes gave a water-splitting current of 10 mA.cm-2. At a current of 20 mA-cm-2, it can operate without degradation for 30 h. This study not only offers a cost-effective solution for water splitting but also provides a new strategy for developing various catalytic nanostructures by changing the metal-organic framework precursors.展开更多
Although lithium-sulfur batteries are one of promising rechargeable energy storage devices,their wide applications are impeded by the lithium polysulfides shutle effect,low electronic conductivity of the cathode,and s...Although lithium-sulfur batteries are one of promising rechargeable energy storage devices,their wide applications are impeded by the lithium polysulfides shutle effect,low electronic conductivity of the cathode,and sluggish redox reaction kinetics of lithium polysulfides.In this work,reduced graphene oxide was decorated with CoSe2 hollow nanospheres to form an RGO-CoSe2 composite that was used as a host material to support S in the cathode.The RGO-CoSe2 composite has the following superiorities:(1)enhanced electronic conductity,(2)accommodation of the volumetric change of cathode materials,(3)effective confinement of numerous lithium polysulfides species due to chemisorption,(4)expedition of the redox kinetics of lithium polysulfides.As expected,the RGO-CoSez-based cathode exhibited the reversible specific capacity of 1,044.7 mAh/g at 0.2C and 695.7 mAh/g at 2C,together with ecellent cycling stability of 0.071% average capacity decay per cycle over 400 cycles at 1C.展开更多
Electrocatalytic oxygen reduction reaction(ORR)provides an attractive alternative to anthraquinone process for H_(2)O_(2) synthesis.Rational design of earth-abundant electrocatalysts for H_(2)O_(2) synthesis via a two...Electrocatalytic oxygen reduction reaction(ORR)provides an attractive alternative to anthraquinone process for H_(2)O_(2) synthesis.Rational design of earth-abundant electrocatalysts for H_(2)O_(2) synthesis via a two-electron ORR process in acids is attractive but still:very challenging.In this work,we report that nitrogen-doped carbon nanotubes as a multi-functional support for CoSe2 nanoparticles not only keep CoSe_(2) nanoparticles well dispersed but alter the crystal structure,which in turn improves the overall catalYtic behaviors and thereby renders high O_(2)-to-H_(2)O_(2) conversion efficiency.In 0.1 M HClO_(4),such CoSe_(2)@NCNTs hybrid delivers a high H_(2)O_(2) selectivity of 93.2% and a large H_(2)0_(2) yield rate of 172 ppm·h^(-1) with excellent durability up to 24 h.Moreover,CoSe_(2)@NCNTs performs effectively for organic dye degradation via electro-Fenton process.展开更多
CoSe2 nanoparticles were synthesized via a facile hydrothermal method, and characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The syn- ...CoSe2 nanoparticles were synthesized via a facile hydrothermal method, and characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The syn- thesized CoSe2 was composed of crystalline orthorhombic phase and displayed a morphology of short and thin nano- belts. The results of the catalyst experiment demonstrate that the CoSe2 nanocrystals show high catalytic activity and methanol tolerance in oxygen reduction reaction(OR_K) with an open circuit potential(OCP) of 0.80 V(vs. NHE) in 0.5 mol/L HzSO4 at 25 ℃. The transfer process of about 3.7 electrons per oxygen molecule was determined during the reduction process and the transfer coefficient and Tafel slope were 0.50 and 118 mV, respectively, in the potential region of 0.64-0.75 V(vs. NHE). The high catalytic activity might be related to the high crystallization of the CoSe2 powder and the modification of selenium on the cobalt element.展开更多
Co9Se8 nanosheets are synthesized via a solvothermal reaction.Thin films of Co9Se8 nanosheets are respectively fabricated through drop-cast and in situ growth for use as the electrocatalyst in dye-sensitized solar cel...Co9Se8 nanosheets are synthesized via a solvothermal reaction.Thin films of Co9Se8 nanosheets are respectively fabricated through drop-cast and in situ growth for use as the electrocatalyst in dye-sensitized solar cells (DSSCs).Comparative studies reveal that the in situ growth Co9Se8 nanosheets film exhibits higher electrocatalytic activity for the electrocatalytic reduction of triiodide to iodide and better electrochemical stability than the drop-casted film.When applied as the counter electrode in DSSCs,the in situ growth film yields higher power conversion efficiency (8.65%) than the drop-casted film (5.87%) and even outperforms the reference Pt electrode (8.16%) under comparable conditions.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51603092 and 21706103)the Natural Science Foundation of Jiangsu Province(Nos.BK20160537 and BK20170549)China Postdoctoral Science Foundation(No.2019T120393)。
文摘Cobalt selenide(CoSe_(2))has become a promising anode material for sodium-ion batteries(SIBs)due to its stable chemical properties,environmental friendliness,and high theoretical capacity.However,the undesirable rate capacity and cycle stability of the anode materials largely limit its applications for SIBs due to the relatively low electronic conductivity and huge volume change during the Na+insertion/extraction.In this study,electrostatic spinning combined with a wet chemical method is employed to synthesize coral-like composite material(CNF@c-CoSe_(2)/C),which is composed of CoSe_(2)/carbon nanosheet arrays(CoSe_(2)/C)and carbon nanofibers(CNFs).CoSe_(2)/C nanoflakes derived from metal-organic frameworks(MOFs)with high surface area and the porous structure can inhibit the pulverization and amorphization of CoSe_(2) during charge and discharge processes,thus significantly keeping the stability of the microstructure.CNF can limit the overgrowth of nanosheets and serve as a conductive skeleton.Compared to two-dimensional CoSe_(2)/C nanoflakes and pure CoSe_(2) nanoparticles,the composite can expose more active sites and effectively accelerate the diffusion of Na+,which displays enhanced rate capability(266.5 mAh·g^(-1) at 5.0 A·g^(-1))and cycling stability(268.3 mAh·g^(-1) after 100 cycles at 1.0 A·g^(-1)).Moreover,the rational preparation strategy for metal selenide-based heterostructure material presents a new way for high-performance SIB s.
基金financial support from the National Natural Science Foundation of China (Grant Nos. 51972191, 51722207)。
文摘Developing bifunctional electrocatalysts with both high catalytic activity and high stability is crucial for efficient water splitting in alkaline media.Herein,a Fe-incorporated dual-metal selenide on nickel foam(Co_(0.9)Fe_(0.1)-Se/NF) is synthesized via a facile one-step electrodeposition method.As-synthesized materials could serve as self-supported bifunctional electrocatalysts with excellent catalytic activity towards oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in alkaline media.Experimental results show that delivering a 10 mA cm^(-2) water splitting current density only requires a cell voltage of 1.55 V.In addition,a very stable performance could be kept for about 36 hours,indicating their excellent working stability.Moreover,by means of phase analysis,we have identified that the evolution of the synthesized Co_(0.9)Fe_(0.1)-Se/NF experiences two entirely different processes in HER and OER,which hydroxide and oxyhydroxide are regarded as the real active sites,respectively.This work may pave the way to further understanding the relationships between the reactivity and stability of chalcogenide-based electrocatalysts and facilitating the rational design of efficient electrocatalysts for future renewable energy system applications.
基金Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2019R1A2C2088047 and NRF-2020R1C1C1003375).
文摘In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state reaction.The method is applied to synthesize an ultrafine CoSe2 nanocrystal@N-doped carbon matrix confined within HMCSs(denoted as CoSe2@NC/HMCS)for use as advanced anodes in highperformance potassium-ion batteries(KIBs).The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework(ZIF-67)within the HMCS templates under vacuum conditions and the subsequent selenization.Thermal treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any solvents.During the subsequent selenization process,the“dual confinement system”,composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS,can effectively suppress the overgrowth of CoSe2 nanocrystals.Thus,the resulting uniquely structured composite exhibits a stable cycling performance(442 mAh g^−1 at 0.1 A g^−1 after 120 cycles)and excellent rate capability(263 mAh g^−1 at 2.0 A g^−1)as the anode material for KIBs.
基金supported by the National Natural Science Foundation of China(51702155,51902036)the National Science Foundation for Distinguished Young Scholars(21625401)+3 种基金the Jiangsu Provincial Founds for Natural Science Foundation(BK20170975)the Natural Science Fund for Colleges and Universities in Jiangsu Province(17KJB480007)the National Key R&D Program of China(Grant No.2017YFA0207202 and 2017YFA0207201)the Natural Science Foundation of Chongqing Science&Technology Commission(No.cstc2019jcyj-msxm X0144)。
文摘Lithium-sulfur battery(Li-S)is considered as one of the new-generation rechargeable batteries with high performance because of its extremely high theoretical capacity,energy density,environmental harmony and low cost.However,low electrical and ionic conductivity of sulfur,safety concerns and parasitic reaction generated by the dissolved polysulfide species in electrolyte hinder the commercialization of Li-S battery.Herein,we report a polyhedral porous structure comprising of carbon coating metal selenide nanoparticles(CoSe2/C),which could not only host sulfur for Li-S battery owing to its porous and conductive structure,but also mitigate the shuttle phenomenon by polysulfides adsorption and catalytic acceleration of redox kinetics.As a result,a performance enhanced CoSe2/C-S electrode for Li-S battery is achieved.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(NRF-2021R1A4A2001687,and NRF-2021R1I1A3057700)。
文摘Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte system.The microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume stress.Consequently,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life stability.For instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.
基金supported by the National Natural Science Foundation of China(21972124,22102105)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionthe support of the Six Talent Peaks Project of Jiangsu Province(XCL-070-2018)。
文摘Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the electron-enriched Pt induced by CoSe_(2)has an efficient bi-functional catalytic ability for alcohol fuels electro-reforming of hydrogen in acid electrolytes.The theoretical calculation revealed the advantages of electron-enriched Pt surface for the adsorption of intermediate,which is well supported by spectroscopic analysis and CO-stripping techniques.Largely improved catalytic performances of activity,durability,and kinetics are demonstrated compared to the conventional alloy system and commercial Pt/C catalyst,due to the efficient synergism of Pt and CoSe_(2);the peak current density of Pt/CoSe_(2)for methanol(ethanol)oxidation is 87.61(48.27)m A cm^(-2),which is about 3.3(2.0)times higher than that of Pt/C catalyst and 2.0(1.5)times that of the traditional PtCo alloy catalysts.Impressively,about 80%of the initial current was found after 1000 cycles of stability test for alcohol fuel oxidation of Pt/CoSe_(2)catalyst,higher than that of Pt/C(ca.50%)and PtCo catalyst(65%).When Pt/CoSe_(2)catalyst serviced as bi-functional catalysts for electrolyzer,a low cell potential of 0.65(0.78)V for methanol(ethanol)electrolysis was required to reach 10 m A cm^(-2),which was about 1030(900)m V less than that of conventional water electrolysis using Pt/C as the catalyst.The current result is instructive for the design of novel bifunctional catalyst and the understanding of hydrogen generation via alcohol fuel electro-reforming.
文摘Cobalt selenide(CoSe_(2))has garnered considerable attention as a prospective anode candidate for advanced lithium-ion storage,prompting comprehensive investigations.However,CoSe_(2)-based anodes usually suffer from significant volume variation upon lithiation leading to unsatisfactory cycling stability.Herein,a versatile synthesis route is proposed for the in-situ fabrication of CoSe2nanoparticles embedded in N-dope carbon skeleton(CoSe_(2)@NC)through annealing treatment and selenization of a metal–organic framework-derived(MOF)precursor.The N-doped carbon derived from the MOF serves not only as an excellent conductive substrate but also as a confined reactor,effectively inhibiting the structural instability and alleviating the inevitable volume change of CoSe_(2).Owing to their unique nanostructure,the as-prepared CoSe_(2)@NC exhibits a high capacity of 745.9mAh·g^(-1)at 0.1 A·g^(-1),while maintaining excellent rate capability and an impressive lifespan.Furthermore,the assembled lithium-ion capacitor(LIC)based on CoSe_(2)@NC demonstrates an energy density of 130Wh·kg^(-1),a power density of 24.6 kW·kg^(-1),and remarkable capacity retention of 90.8%after 8000 cycles.These results highlight the great potential of CoSe_(2)@NC for practical applications.
基金supported by the National Natural Science Foundation of China(Nos.52174286,22105190)Natural Science Foundation of Hunan Province in China(2023JJ10068)Innovation-Driven Project of Central South University(No.2020CX007).
文摘Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe_(2)@NC@NCNFs bifunctional catalyst was designed and fabricated by confining cubic CoSe_(2)nanoparticles to three-dimensional(3D)porous MOFs-derived nitrogen-doped carbon(NC)and one-dimensional(1D)N-doped carbon nanofibers(NCNFs)through a facile encapsulate strategy.The 1D/3D continuous network structure contributes to the improvement of specific surface area and electronic conductivity,while the strong synergistic effect between CoSe_(2)sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion resistance.The as-constructed CoSe_(2)@NC@NCNFs catalyst exhibits high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V(vs.RHE)in ORR and a low overpotential of 280 mV at 10 mA·cm^(−2)in OER.More encouragingly,the rechargeable ZABs with CoSe_(2)@NC@NCNFs cathode deliver high peak power densities(126.8 mW·cm^(−2)),large specific capacities(763.1 mA·h·g^(−1)),and robust charge-discharge cycling stability over 240 cycles.This study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.
基金financially supported by the National Natural Science Foundation of China (No. 21972107)Natural Science Foundation of Jiangsu Province (No. BK20191186)Natural Science Foundation of Hubei Province (No. 2020CFA095)。
文摘The development of high-performance non-precious metal-based robust bifunctional electrocatalyst for both hydrogen evolution reaction(HER) and oxygen evolution reactions(OER) in alkaline media is essential for the electrochemical overall water splitting technologies. Herein, we demonstrate that the HER/OER performance of Co Se_(2)can be significantly enhanced by tuning the 3d-orbital electron filling degree through Mo doping. Both density functional theory(DFT) calculations and experimental results imply that the doping of Mo with higher proportion of the unoccupied d-orbital(P_(un)) could not only serve as the active center for water adsorption to enhance the water molecule activation, but also modulate the electronic structures of Co metal center leading to the optimized adsorption strength of*H. As expected, the obtained Mo-Co Se_(2)exhibits a remarkable bifunctional performance with overpotential of only 85 m V for HER and 245 m V for OER to achieve the current density of 10 m A/cm^(2)in alkaline media.This work will provide a valuable insight to design highly efficient bifunctional electrocatalyst towards HER and OER.
基金The project is supported by the National Natural Science Foundation of China (Nos. 21275076 and 61328401), Jiangsu Provincial Founds for Distinguished Young Scholars (No. BK20130046), Key University Science Research Project of Jiangsu Province (No. 15KJA430006), Program for New Century Excellent Talents in University (No. NCET-13-0853), QingLan Project, Nantong Key Laboratory of New Materials Industrial Technology, SERC Grant (#102170 0142) from A'STAR Singapore, the scholarship from China Scholarships Council (No. 201508320304).
文摘The development of efficient, low-cost, for water splitting, particularly those stable, non-noble-metal electrocatalysts that can catalyze both the hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode, is a challenge. We have developed a facile method for synthesizing CoSe2 nanoparticles uniformly anchored on carbon fiber paper (CoSe2/CF) via pyrolysis and selenization of in situ grown zeolitic imidazolate framework-67 (ZIF-67). CoSe2/CF shows high and stable catalytic activity in both the HER and OER in alkaline solution. At a low cell potential, i.e., 1.63 V, a water electrolyzer equipped with two CoSe2/CF electrodes gave a water-splitting current of 10 mA.cm-2. At a current of 20 mA-cm-2, it can operate without degradation for 30 h. This study not only offers a cost-effective solution for water splitting but also provides a new strategy for developing various catalytic nanostructures by changing the metal-organic framework precursors.
基金the National Natural Science Foundation of China(No.51802029)Natural Science Foundation of Hunan Province,China(No.2017JJ3343)+2 种基金Scientific Research Fund of Hunan Provincial Education Department(No.17B028)Project of Changsha bureau of science and technology(No.k1705062)Scientific Research for The Introduction of Talents of Changsha University(No.SF1606).
文摘Although lithium-sulfur batteries are one of promising rechargeable energy storage devices,their wide applications are impeded by the lithium polysulfides shutle effect,low electronic conductivity of the cathode,and sluggish redox reaction kinetics of lithium polysulfides.In this work,reduced graphene oxide was decorated with CoSe2 hollow nanospheres to form an RGO-CoSe2 composite that was used as a host material to support S in the cathode.The RGO-CoSe2 composite has the following superiorities:(1)enhanced electronic conductity,(2)accommodation of the volumetric change of cathode materials,(3)effective confinement of numerous lithium polysulfides species due to chemisorption,(4)expedition of the redox kinetics of lithium polysulfides.As expected,the RGO-CoSez-based cathode exhibited the reversible specific capacity of 1,044.7 mAh/g at 0.2C and 695.7 mAh/g at 2C,together with ecellent cycling stability of 0.071% average capacity decay per cycle over 400 cycles at 1C.
基金supported by the National Natural Science Foundation of China(Nos.22072015,21878195 and U20A20145)the Scientific and technological achievement transformation project of Sichuan Science and Technology Department(No.21ZHSF0111Shanghai Scientific and Technological Innovation Project(No.18JC1410604).
文摘Electrocatalytic oxygen reduction reaction(ORR)provides an attractive alternative to anthraquinone process for H_(2)O_(2) synthesis.Rational design of earth-abundant electrocatalysts for H_(2)O_(2) synthesis via a two-electron ORR process in acids is attractive but still:very challenging.In this work,we report that nitrogen-doped carbon nanotubes as a multi-functional support for CoSe2 nanoparticles not only keep CoSe_(2) nanoparticles well dispersed but alter the crystal structure,which in turn improves the overall catalYtic behaviors and thereby renders high O_(2)-to-H_(2)O_(2) conversion efficiency.In 0.1 M HClO_(4),such CoSe_(2)@NCNTs hybrid delivers a high H_(2)O_(2) selectivity of 93.2% and a large H_(2)0_(2) yield rate of 172 ppm·h^(-1) with excellent durability up to 24 h.Moreover,CoSe_(2)@NCNTs performs effectively for organic dye degradation via electro-Fenton process.
基金the Natural Science Foundation of Heilongjiang Province of China(No.B201423), the Science and Technology Project of Suihua City of China(No.KJZD20130086), the Scientific Research Fund of Heilongjiang Provincial Education Department, China(No 12541938) and the Doctor Scientific Research Fund of Suihua University, China(No. SD 13001).
文摘CoSe2 nanoparticles were synthesized via a facile hydrothermal method, and characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The syn- thesized CoSe2 was composed of crystalline orthorhombic phase and displayed a morphology of short and thin nano- belts. The results of the catalyst experiment demonstrate that the CoSe2 nanocrystals show high catalytic activity and methanol tolerance in oxygen reduction reaction(OR_K) with an open circuit potential(OCP) of 0.80 V(vs. NHE) in 0.5 mol/L HzSO4 at 25 ℃. The transfer process of about 3.7 electrons per oxygen molecule was determined during the reduction process and the transfer coefficient and Tafel slope were 0.50 and 118 mV, respectively, in the potential region of 0.64-0.75 V(vs. NHE). The high catalytic activity might be related to the high crystallization of the CoSe2 powder and the modification of selenium on the cobalt element.
文摘Co9Se8 nanosheets are synthesized via a solvothermal reaction.Thin films of Co9Se8 nanosheets are respectively fabricated through drop-cast and in situ growth for use as the electrocatalyst in dye-sensitized solar cells (DSSCs).Comparative studies reveal that the in situ growth Co9Se8 nanosheets film exhibits higher electrocatalytic activity for the electrocatalytic reduction of triiodide to iodide and better electrochemical stability than the drop-casted film.When applied as the counter electrode in DSSCs,the in situ growth film yields higher power conversion efficiency (8.65%) than the drop-casted film (5.87%) and even outperforms the reference Pt electrode (8.16%) under comparable conditions.