A new non-isothermal method of kinetic analysis was employed to investigate the thermal decomposition kinetic modeling of the basic carbonate cobalt nanosheets（n-BCoC） synthesized from spent lithium-ion batteries（L...A new non-isothermal method of kinetic analysis was employed to investigate the thermal decomposition kinetic modeling of the basic carbonate cobalt nanosheets（n-BCoC） synthesized from spent lithium-ion batteries（LIBs）. Fraser–Suzuki function was applied to deconvoluting overlapping complex processes from the overall differential thermal curves obtained under the linear heating rate conditions, followed by the kinetic analysis of the discrete processes using a new kinetic analysis method. Results showed that the decomposition of n-BCo C in air occurred through two consecutive reactions in the 136-270 ℃ temperature intervals. Decomposition started by hydroxide component（Co（OH）2） decomposition until to 65% and simultaneously carbonate phase decarbonation began. The process was continued by CO2 evolution and finally carbonate cobalt nanosheets have been produced. The reaction mechanism of the whole process can be kinetically characterized by two successive reactions： a phase boundary contracting reaction followed by an Avrami-Erofeev equation. Mechanistic information obtained by the kinetic study was in good agreement with FT-IR（Fourier transform infrared spectroscopy） and SEM（scanning electron microscopy） results.展开更多
The controllable and safe hydrogen storage technologies are widely recognized as the main bottleneck for the accomplishment of sustainable hydrogen energy.Ammonia borane(AB)has regarded as a competitive candidate for ...The controllable and safe hydrogen storage technologies are widely recognized as the main bottleneck for the accomplishment of sustainable hydrogen energy.Ammonia borane(AB)has regarded as a competitive candidate for chemical hydrogen storage.However,developing efficient yet high-performance catalysts towards hydrogen evolution from AB hydrolysis remains an enormous challenge.Herein,cobalt phosphide nanosheets are synthesized by a facile salt-assisted along with low-temperature phosphidation strategy for simultaneously modulating its morphology and electronic structure,and function as hydrogen evolution photocatalysts.Impressively,the Co_(2)P nanosheets display extraordinary performance with a record high turnover frequency of 44.9 min^(-1),outperforming most of the noble-metal-free catalysts reported to date.This remarkable performance is attributed to its desired nanosheets structure,featuring with high specific surface area,abundant exposed active sites,and short charge diffusion paths.Our findings provide a novel strategy for regulating metal phosphides with desired phase structure and morphology for energy-related applications and beyond.展开更多
Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air...Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.展开更多
Theranostic nanoagents that integrate the diagnoses and therapies within a single nanomaterial are compelling in their use for highly precise and efficient antitumor treatments. Herein, polyethylene glycol （PEG）-mod...Theranostic nanoagents that integrate the diagnoses and therapies within a single nanomaterial are compelling in their use for highly precise and efficient antitumor treatments. Herein, polyethylene glycol （PEG）-modified cobalt sulfide nanosheets （CoS-PEG NSs） are synthesized and unitized as a powerful theranostic nanoagent for efficient photothermal conversion and multimodal imaging for the first time. We demonstrate that the obtained CoS-PEG NSs show excellent compatibility and stability in water and various physiological solutions, and can be effectively inter- nalized by cells, but exhibit a low cytotoxicity. The CoS-PEG NSs exhibit an efficient photothermal conversion capacity, benefited from the strong near-infrared （NIR） absorption, high photothermal conversion efficiency （~ 33.0%）, and excellent photo- thermal stability. Irnportant136 the highly effective photothermal killing effect on cancer ceils after exposure to CoS-PEG NSs plus laser irradiation has been con- firmed by both the standard Cell Counting Kit-8 and live-dead cell staining assays, revealing a concentration-dependent photothermal therapeutic effect. Moreover, utilizing the strong NIR absorbance together with the T2-MR contrast ability of the CoS-PEG NSs, a high-contrast triple-modal imaging, i.e., photoacoustic （PA）, infrared thermal （IRT）, and magnetic resonance （MR） imaging, can be achieved, suggesting a great potential for multimodal imaging to provide comprehensive cancer diagnosis. Our work introduces the first bioapplication of the CoS-PEG nanomaterial as a potential theranostic nanoplatform and may promote further rational design of CoS-based nanostructures for precise/effident cancer diagnosis and therapy.展开更多
Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exh...Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exhibited a high capacity, fast kinetics, and a long cycle life. This CoP/CNS composite contained small CoP particles （approximately 11.3 nm） and P-C bonds. When its electrochemical properties were evaluated by testing CoP/Na coin cells, the composite delivered a Na-storage capacity of 598 mAh·g-1 at 0.1 A·g-1 according to the total mass of the composite, which means that the capacity of pure CoP reached 831 mAh·g-1 The composite also exhibited a high rate capability and long-term cyclability （174 mAh·g-1 at 20 A·g-1 and 98.5% capacity retention after 900 cycles at 1 A·g-1）, which are commonly attributed to robust P-C bonding and highly conductive CNSs. When the reaction mechanism of the CoP/CNS composite was investigated, a conversion reaction expressed as CoP ＋ 3Na＋ ＋ 3e＋＋ Co ＋ Na3P was observed. The outstanding Na-storage properties of the CoP/CNS composite may suggest a new strategy for developing high-performance anode materials for Na-ion batteries.展开更多
In this work,cobalt glycerate(CoG@F127)nanosheets grown on the surface of graphene oxide(GO),i.e.CoG@F127/GO,have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method.Aft...In this work,cobalt glycerate(CoG@F127)nanosheets grown on the surface of graphene oxide(GO),i.e.CoG@F127/GO,have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method.After calcination,CoG@F127/GO is transformed into one derivative,Co nanoparticles coated with a trace amount of carbon(Co-C)on GO(Co-C/GO).The Co nanoparticles consist of an atypical core-shell structure,in which the core and the shell are both Co.Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction(HER)to significantly improve the catalyst activity of HER.CoG@F127/GO is phosphatized to form the other derivate,cobalt pyrophosphate coated with a small amount of carbon(Co_(2)P_(2)O_(7)-C)on GO(Co_(2)P_(2)O_(7)-C/GO).Co_(2)P_(2)O_(7)-C/GO composite owns a large electrochemical active surface area(ECSA)and fast rate towards oxygen evolution reaction(OER).Furthermore,the two derivatives of CoG@F127/GO,i.e.Co-C/GO and Co_(2)P_(2)O_(7)-C/GO as twin flowers,are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm^(-2).展开更多
Novel zinc-nickel-cobalt ternary oxide nanosheets were successfully synthesized via an easy solvothermal method followed by calcination and were tailored to have different numbers of wrinkles by controlling the vohtrn...Novel zinc-nickel-cobalt ternary oxide nanosheets were successfully synthesized via an easy solvothermal method followed by calcination and were tailored to have different numbers of wrinkles by controlling the vohtrne ratio of the components in the mixed solvent. Nanosheets with more wrinkles yielded a large specific surface area（111.61 m2/g）, which improved their electrochemical properties. The resulting products were characterized using a three-electrode system in 6 mol/L KOH electrolyte solution. With unique structures, the nanosheets with more wrinkles displayed a good capacitive behavior and an excellent specific capacitance retention of 97.18% after 2000 continuous charge-discharge cycles. Considering their high electrochemical performance and simple fabrication, we proposed that these unique zinc-nickel-cobalt oxide nanosheets are promising supercapacitor electrodes for energy storage applications.展开更多
基金supported by the Iranian National Science Foundation (INSF)
文摘A new non-isothermal method of kinetic analysis was employed to investigate the thermal decomposition kinetic modeling of the basic carbonate cobalt nanosheets（n-BCoC） synthesized from spent lithium-ion batteries（LIBs）. Fraser–Suzuki function was applied to deconvoluting overlapping complex processes from the overall differential thermal curves obtained under the linear heating rate conditions, followed by the kinetic analysis of the discrete processes using a new kinetic analysis method. Results showed that the decomposition of n-BCo C in air occurred through two consecutive reactions in the 136-270 ℃ temperature intervals. Decomposition started by hydroxide component（Co（OH）2） decomposition until to 65% and simultaneously carbonate phase decarbonation began. The process was continued by CO2 evolution and finally carbonate cobalt nanosheets have been produced. The reaction mechanism of the whole process can be kinetically characterized by two successive reactions： a phase boundary contracting reaction followed by an Avrami-Erofeev equation. Mechanistic information obtained by the kinetic study was in good agreement with FT-IR（Fourier transform infrared spectroscopy） and SEM（scanning electron microscopy） results.
基金supported by the National Natural Science Foundation of China(22108238,21878259)the Zhejiang Provincial Natural Science Foundation of China(LR18B060001)+5 种基金Anhui Provincial Natural Science Founda-tion(1908085QB68)the Natural Science Foundation of the Anhui Higher Education Institutions of China(KJ2020A0275)Major Science and Technology Project of Anhui Province(201903a05020055)Foundation of Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology(ZJKL-ACEMT-1802)China Postdoctoral Science Foundation(2019M662060,2020T130580)Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology(BM2012110).
文摘The controllable and safe hydrogen storage technologies are widely recognized as the main bottleneck for the accomplishment of sustainable hydrogen energy.Ammonia borane(AB)has regarded as a competitive candidate for chemical hydrogen storage.However,developing efficient yet high-performance catalysts towards hydrogen evolution from AB hydrolysis remains an enormous challenge.Herein,cobalt phosphide nanosheets are synthesized by a facile salt-assisted along with low-temperature phosphidation strategy for simultaneously modulating its morphology and electronic structure,and function as hydrogen evolution photocatalysts.Impressively,the Co_(2)P nanosheets display extraordinary performance with a record high turnover frequency of 44.9 min^(-1),outperforming most of the noble-metal-free catalysts reported to date.This remarkable performance is attributed to its desired nanosheets structure,featuring with high specific surface area,abundant exposed active sites,and short charge diffusion paths.Our findings provide a novel strategy for regulating metal phosphides with desired phase structure and morphology for energy-related applications and beyond.
基金financially supported by the National Natural Science Foundation of China (Nos. 21506081, 21705058, 21676126)the Provincial Natural Science Foundation of Jiangsu (Nos. BK20170524, BK20160492)+2 种基金China Postdoctoral Science Foundation (No. 2018T110450)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsThe financial support from an ARC Discovery Project (No. DP180102003)
文摘Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.
基金This work was financially supported by the National Natural Science Foundation of China （NSFC） （Nos. 21473045 and 51401066）, the Fundamental Research Funds from the Central University （PIRSOF HIT A201503）, and the State Key Laboratory of Urban Water Resource and Environment, the Harbin Institute of Technology （No. 2018DX04）.
文摘Theranostic nanoagents that integrate the diagnoses and therapies within a single nanomaterial are compelling in their use for highly precise and efficient antitumor treatments. Herein, polyethylene glycol （PEG）-modified cobalt sulfide nanosheets （CoS-PEG NSs） are synthesized and unitized as a powerful theranostic nanoagent for efficient photothermal conversion and multimodal imaging for the first time. We demonstrate that the obtained CoS-PEG NSs show excellent compatibility and stability in water and various physiological solutions, and can be effectively inter- nalized by cells, but exhibit a low cytotoxicity. The CoS-PEG NSs exhibit an efficient photothermal conversion capacity, benefited from the strong near-infrared （NIR） absorption, high photothermal conversion efficiency （~ 33.0%）, and excellent photo- thermal stability. Irnportant136 the highly effective photothermal killing effect on cancer ceils after exposure to CoS-PEG NSs plus laser irradiation has been con- firmed by both the standard Cell Counting Kit-8 and live-dead cell staining assays, revealing a concentration-dependent photothermal therapeutic effect. Moreover, utilizing the strong NIR absorbance together with the T2-MR contrast ability of the CoS-PEG NSs, a high-contrast triple-modal imaging, i.e., photoacoustic （PA）, infrared thermal （IRT）, and magnetic resonance （MR） imaging, can be achieved, suggesting a great potential for multimodal imaging to provide comprehensive cancer diagnosis. Our work introduces the first bioapplication of the CoS-PEG nanomaterial as a potential theranostic nanoplatform and may promote further rational design of CoS-based nanostructures for precise/effident cancer diagnosis and therapy.
文摘Cobalt phosphide （COP） nanoparticles which were uniformly embedded in N-doped C nanosheets （CNSs） were fabricated via the simple one-step calcination of a Co-based metal-organic framework （MOF） and red P and exhibited a high capacity, fast kinetics, and a long cycle life. This CoP/CNS composite contained small CoP particles （approximately 11.3 nm） and P-C bonds. When its electrochemical properties were evaluated by testing CoP/Na coin cells, the composite delivered a Na-storage capacity of 598 mAh·g-1 at 0.1 A·g-1 according to the total mass of the composite, which means that the capacity of pure CoP reached 831 mAh·g-1 The composite also exhibited a high rate capability and long-term cyclability （174 mAh·g-1 at 20 A·g-1 and 98.5% capacity retention after 900 cycles at 1 A·g-1）, which are commonly attributed to robust P-C bonding and highly conductive CNSs. When the reaction mechanism of the CoP/CNS composite was investigated, a conversion reaction expressed as CoP ＋ 3Na＋ ＋ 3e＋＋ Co ＋ Na3P was observed. The outstanding Na-storage properties of the CoP/CNS composite may suggest a new strategy for developing high-performance anode materials for Na-ion batteries.
基金The funding support from the National Natural Science Foundation of China(Grant No.21773203)the“Qinglan project”of Jiangsu Province(2018-12)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions is acknowledged。
文摘In this work,cobalt glycerate(CoG@F127)nanosheets grown on the surface of graphene oxide(GO),i.e.CoG@F127/GO,have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method.After calcination,CoG@F127/GO is transformed into one derivative,Co nanoparticles coated with a trace amount of carbon(Co-C)on GO(Co-C/GO).The Co nanoparticles consist of an atypical core-shell structure,in which the core and the shell are both Co.Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction(HER)to significantly improve the catalyst activity of HER.CoG@F127/GO is phosphatized to form the other derivate,cobalt pyrophosphate coated with a small amount of carbon(Co_(2)P_(2)O_(7)-C)on GO(Co_(2)P_(2)O_(7)-C/GO).Co_(2)P_(2)O_(7)-C/GO composite owns a large electrochemical active surface area(ECSA)and fast rate towards oxygen evolution reaction(OER).Furthermore,the two derivatives of CoG@F127/GO,i.e.Co-C/GO and Co_(2)P_(2)O_(7)-C/GO as twin flowers,are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm^(-2).
基金Supported by the National Natural Science Foundation of China（Nos.51372124, 51572134）.
文摘Novel zinc-nickel-cobalt ternary oxide nanosheets were successfully synthesized via an easy solvothermal method followed by calcination and were tailored to have different numbers of wrinkles by controlling the vohtrne ratio of the components in the mixed solvent. Nanosheets with more wrinkles yielded a large specific surface area（111.61 m2/g）, which improved their electrochemical properties. The resulting products were characterized using a three-electrode system in 6 mol/L KOH electrolyte solution. With unique structures, the nanosheets with more wrinkles displayed a good capacitive behavior and an excellent specific capacitance retention of 97.18% after 2000 continuous charge-discharge cycles. Considering their high electrochemical performance and simple fabrication, we proposed that these unique zinc-nickel-cobalt oxide nanosheets are promising supercapacitor electrodes for energy storage applications.
