As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of z...As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of zinc ions.The strength for uorescence of BVE-Zn^2+ complex is greatly enhanced and uorescence quantum yield can increase to5%.Herein,we studied ultrafast excited state dynamics of BVE-Zn^2+ complex in ethanol,npropanol,and DMSO solutions in order to reveal the mechanism of uorescence quantum yield enhancement.The results show that BVE can form a stable coordination complex with zinc with 1:1 stoichiometry in solution.BVE is structurally and energetically more stable in the complex.Using picosecond time-resolve uorescence and femtosecond transient absorption spectroscopy,we show that smaller non-radiative rate constant of BVE-Zn^2+ complex in DMSO is the key to increasing its uorescence quantum yield and the excited state decay mechanism is also revealed.These results provide valuable information about the uorescence property change after BVE binding to metal ions and may provide a guidance for the study of phytochromes or other uorescence proteins in which BV/BVE acts as chromophores.展开更多
Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries(AZIBs).In this work,we desi...Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries(AZIBs).In this work,we designed to grow zeolitic imidazolate framework-8(ZIF-8)uniformly on CuO nanosheets(NSs)and prepared carbon-coated CuZn alloy NSs(CuZn@C NSs)by calcination under H_(2)/Ar atmosphere.As reflected by extended X-ray absorption fine structure(EXAFS),density functional theory(DFT),in-situ Raman,the Cu–Zn and Zn–N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn dendrites.At the same time,CuZn@C NSs hinder the direct contact between zinc anode and electrolyte,preventing the occurrence of side reactions.More impressively,the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage hysteresis.In addition,low polarization,high capacity retention,long cycle life over 1000 cycles at 5 A∙g^(−1) were achieved when CuZn@C NSs were used as anodes for CuZn@C/V_(2)O_(5)full cells.展开更多
Constructing two-dimensional(2D)structures for transition-metal oxides(TMOs)can optimize their electronic structures and enable high specific surface areas,thereby offering routes to enhancing the performance of TMOs ...Constructing two-dimensional(2D)structures for transition-metal oxides(TMOs)can optimize their electronic structures and enable high specific surface areas,thereby offering routes to enhancing the performance of TMOs in energy storage and conversion.However,most 2D TMOs,e.g.,Fe_(2)O^(3),remain so far synthetically challenging due to their intrinsic non-layered structures.Herein,inspired by the mechanism of biomineralization,we report the synthesis of CuO/Fe_(2)O^(3)hybrid ultrathin nanosheets by using polyvinylpyrrolidone-decorated CuO nanosheets as growth modifiers to modulate the hydrolysis process of Fe^(2+).The formulated“absorption-and-crystallization”two-step formation processes of such 2D hybrid structures accorded well with the biomineralization scheme in nature.Combining the in-situ transmission electron microscopy(TEM)study,theoretical calculation,and control experiments,we validated that the large density of 2D/2D interfaces enabled by this bio-inspired synthesis process can overcome the self-stacking phenomenon during lithium-ion battery cycling,leading to their high operation stability.This work emphasizes the bio-inspired synthesis of 2D TMOs as a promising pathway toward material design and performance optimization.展开更多
Nowadays,Cu-based materials have attracted extensive attention as electrocatalysts,while the inherent reason of the filling of high anti-bonding state of Cu d band(3 d^(10)4 s^(1))makes it difficult to hybridize with ...Nowadays,Cu-based materials have attracted extensive attention as electrocatalysts,while the inherent reason of the filling of high anti-bonding state of Cu d band(3 d^(10)4 s^(1))makes it difficult to hybridize with O2 p band of oxygen intermediates during the adsorption process of oxygen evolution reaction(OER).To increase the efficiency of Cu-based electrocatalysts,efforts have been made to optimize the electronic structures and to create surface defects and hierarchical nanostructures with more exposed accessible active sites.Herein,we report a facile method for preparing CuO electrocatalysts with hierarchical nanostructures using the Cu-alanine complex as a precursor through room-temperature chemical precipitation and subsequent calcination in air.Investigations of products obtained at different calcination temperatures reveal the relationship between OER activities and the material characteristics such as specific surface areas,crystal growth orientations,and element components.The product obtained at 500℃exhibits the smallest overpotential of 290 mV in 1.0 mol/L KOH for electrocatalyzing OER.Combining with various characterizations of CuO electrocatalysts after OER activities,the possible catalytic mechanism and the influence factors of their OER performance are also discussed.展开更多
The increasing demand for the state-of-the-art transparent conductive electrodes has received great interest in synthesizing silver nanowires(AgNWs)with a uniform diameter that exhibit excellent conductance,transparen...The increasing demand for the state-of-the-art transparent conductive electrodes has received great interest in synthesizing silver nanowires(AgNWs)with a uniform diameter that exhibit excellent conductance,transparency,flexibility and mechanical ductility.Herein,we report the controllable synthesis of ultrathin AgNWs with high aspect ratio via a polyol-assisted process.The diameter of AgNWs can be continuously modulated from 20 to 80 nm by simply adjusting the aging time.The selfassembled films fabricated by using AgNWs with a diameter of 20 nm as building blocks enable an excellent performance and show a sheet resistance of^30Ω/sq and an optical transmittance of 94%.In addition,such nanowire-based conductive films can keep the excellent flexibility and resistance after bending 10,000 cycles.Similarly,the intelligent dimming films prepared by this AgNW films also have excellent flexibility and stability.展开更多
基金the National Nature Science Foundation of China(No.11674101,No.21873030 and No.91850202)。
文摘As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of zinc ions.The strength for uorescence of BVE-Zn^2+ complex is greatly enhanced and uorescence quantum yield can increase to5%.Herein,we studied ultrafast excited state dynamics of BVE-Zn^2+ complex in ethanol,npropanol,and DMSO solutions in order to reveal the mechanism of uorescence quantum yield enhancement.The results show that BVE can form a stable coordination complex with zinc with 1:1 stoichiometry in solution.BVE is structurally and energetically more stable in the complex.Using picosecond time-resolve uorescence and femtosecond transient absorption spectroscopy,we show that smaller non-radiative rate constant of BVE-Zn^2+ complex in DMSO is the key to increasing its uorescence quantum yield and the excited state decay mechanism is also revealed.These results provide valuable information about the uorescence property change after BVE binding to metal ions and may provide a guidance for the study of phytochromes or other uorescence proteins in which BV/BVE acts as chromophores.
基金the National Natural Science Foundation of China(Nos.NSFC-U1904215,21805192,and 12102422)the Natural Science Foundation of Jiangsu Province(No.BK20200044)+2 种基金the Top-notch Academic Programs Project(TAPP)of Jiangsu Higher Education Institutions,and the Program for Young Changjiang Scholars of the Ministry of Education,China(No.Q2018270)We also acknowledge the Priority Academic Program Development of Jiangsu Higher Education Institutions.Y.Y.L.acknowledges the Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110735)the Natural Science Research Project of Anhui Educational Committee for Excellent Young Scholars(No.2022AH030152).
文摘Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries(AZIBs).In this work,we designed to grow zeolitic imidazolate framework-8(ZIF-8)uniformly on CuO nanosheets(NSs)and prepared carbon-coated CuZn alloy NSs(CuZn@C NSs)by calcination under H_(2)/Ar atmosphere.As reflected by extended X-ray absorption fine structure(EXAFS),density functional theory(DFT),in-situ Raman,the Cu–Zn and Zn–N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn dendrites.At the same time,CuZn@C NSs hinder the direct contact between zinc anode and electrolyte,preventing the occurrence of side reactions.More impressively,the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage hysteresis.In addition,low polarization,high capacity retention,long cycle life over 1000 cycles at 5 A∙g^(−1) were achieved when CuZn@C NSs were used as anodes for CuZn@C/V_(2)O_(5)full cells.
基金Acknowledgements This work was handed by the National Natural Science Foundation of China （Nos. 21521001, 21431006, 21061160492, and J1030412）, the National Basic Research Program of China （Nos. 2014CB931800 and 2013CB933900）, the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS （Nos. 2015HSC-UE007 and 2015SRG-HSC038）, and the Chinese Academy of Sciences （No. KJZD-EW-M01-1）.
基金supported by the National Natural Science Foundation of China(Nos.U1932213,51732011,81788101,11227901,and 21805192)the National key Research and Development Program of China(No.2021YFA0715700)+7 种基金the National Basic Research Program of China(No.2021YFA0715700)the National Key Research and Development Program of China(No.2018YFE0202201)Science and Technology Major Project of Anhui Province(No.201903a05020003)the Fundamental Research Funds for the Central Universities(No.WK2060000031)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040502)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110735)China Postdoctoral Science Foundation(No.2020M671612)Jiangsu Postdoctoral Science Foundation(No.2020Z082)。
文摘Constructing two-dimensional(2D)structures for transition-metal oxides(TMOs)can optimize their electronic structures and enable high specific surface areas,thereby offering routes to enhancing the performance of TMOs in energy storage and conversion.However,most 2D TMOs,e.g.,Fe_(2)O^(3),remain so far synthetically challenging due to their intrinsic non-layered structures.Herein,inspired by the mechanism of biomineralization,we report the synthesis of CuO/Fe_(2)O^(3)hybrid ultrathin nanosheets by using polyvinylpyrrolidone-decorated CuO nanosheets as growth modifiers to modulate the hydrolysis process of Fe^(2+).The formulated“absorption-and-crystallization”two-step formation processes of such 2D hybrid structures accorded well with the biomineralization scheme in nature.Combining the in-situ transmission electron microscopy(TEM)study,theoretical calculation,and control experiments,we validated that the large density of 2D/2D interfaces enabled by this bio-inspired synthesis process can overcome the self-stacking phenomenon during lithium-ion battery cycling,leading to their high operation stability.This work emphasizes the bio-inspired synthesis of 2D TMOs as a promising pathway toward material design and performance optimization.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.U1904215,21671170,21673203,21805192 and 21875207)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)+5 种基金the Six Talent Plan(No.2015-XCL-030)the Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110735)China Postdoctoral Science Foundation(No.2020M671612)Jiangsu Province Postdoctoral Science Foundation(No.2020Z082)Excellent Doctoral Dissertation of Yangzhou University and Undergraduate Scientific Research Innovation Projects in Jiangsu Province(No.201911117036Z)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Nowadays,Cu-based materials have attracted extensive attention as electrocatalysts,while the inherent reason of the filling of high anti-bonding state of Cu d band(3 d^(10)4 s^(1))makes it difficult to hybridize with O2 p band of oxygen intermediates during the adsorption process of oxygen evolution reaction(OER).To increase the efficiency of Cu-based electrocatalysts,efforts have been made to optimize the electronic structures and to create surface defects and hierarchical nanostructures with more exposed accessible active sites.Herein,we report a facile method for preparing CuO electrocatalysts with hierarchical nanostructures using the Cu-alanine complex as a precursor through room-temperature chemical precipitation and subsequent calcination in air.Investigations of products obtained at different calcination temperatures reveal the relationship between OER activities and the material characteristics such as specific surface areas,crystal growth orientations,and element components.The product obtained at 500℃exhibits the smallest overpotential of 290 mV in 1.0 mol/L KOH for electrocatalyzing OER.Combining with various characterizations of CuO electrocatalysts after OER activities,the possible catalytic mechanism and the influence factors of their OER performance are also discussed.
基金supported by the National Natural Science Foundation of China(51572067,21501039,21701165,51732011,21761132008,51502281,21805192)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(21521001)+2 种基金Key Research Program of Frontier Sciences,CAS(QYZDJSSWSLH036)the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS(2015HSC-UE007)the Fundamental Research Funds for the Central Universities(JZ2018HGPA0269)。
文摘The increasing demand for the state-of-the-art transparent conductive electrodes has received great interest in synthesizing silver nanowires(AgNWs)with a uniform diameter that exhibit excellent conductance,transparency,flexibility and mechanical ductility.Herein,we report the controllable synthesis of ultrathin AgNWs with high aspect ratio via a polyol-assisted process.The diameter of AgNWs can be continuously modulated from 20 to 80 nm by simply adjusting the aging time.The selfassembled films fabricated by using AgNWs with a diameter of 20 nm as building blocks enable an excellent performance and show a sheet resistance of^30Ω/sq and an optical transmittance of 94%.In addition,such nanowire-based conductive films can keep the excellent flexibility and resistance after bending 10,000 cycles.Similarly,the intelligent dimming films prepared by this AgNW films also have excellent flexibility and stability.
