The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical perfo...The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical performance.Herein,metallic Cu_(2)Se encapsulated with N-doped carbon(Cu_(2)Se@NC)was prepared using Cu_(2)O nanocubes as templates through a combination of dopamine polymerization and hightemperature selenization.The unique nanocubic structure and uniform N-doped carbon coating could shorten the ion transport distance,accelerate electron/charge diffusion,and suppress volume variation,ultimately ensuring Cu_(2)Se@NC with excellent electrochemical performance in sodium ion batteries(SIBs)and potassium ion batteries(PIBs).The composite exhibited excellent rate performance(187.7 mA h g^(-1)at 50 A g^(-1)in SIBs and 179.4 mA h g^(-1)at 5 A g^(-1)in PIBs)and cyclic stability(246,8 mA h g^(-1)at 10 A g^(-1)in SIBs over 2500 cycles).The reaction mechanism of intercalation combined with conversion in both SIBs and PIBs was disclosed by in situ X-ray diffraction(XRD)and ex situ transmission electron microscope(TEM).In particular,the final products in PIBs of K_(2)Se and K_(2)Se_(3)species were determined after discharging,which is different from that in SIBs with the final species of Na_(2)Se.The density functional theory calculation showed that carbon induces strong coupling and charge interactions with Cu_(2)Se,leading to the introduction of built-in electric field on heterojunction to improve electron mobility.Significantly,the theoretical calculations discovered that the underlying cause for the relatively superior rate capability in SIBs to that in PIBs is the agile Na~+diffusion with low energy barrier and moderate adsorption energy.These findings offer theoretical support for in-depth understanding of the performance differences of Cu-based materials in different ion storage systems.展开更多
The nanoporous Cu_(2-x)Se with Cu(Se-5%)surface catalysts were prepared through in situ dynamic restructuring strategy during the electrochemical process,which achieves highly selective electrochemical CO_(2) reductio...The nanoporous Cu_(2-x)Se with Cu(Se-5%)surface catalysts were prepared through in situ dynamic restructuring strategy during the electrochemical process,which achieves highly selective electrochemical CO_(2) reduction to methanol.In situ and quasi-operando spectroscopic results provide a deep insight into the catalytic active centres of reconstructed heterogeneous catalysts for CO_(2) electroreduction.展开更多
Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize se...Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.展开更多
Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architectur...Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architecture with a facile strategy is still challenging.Here we report that a polycrystalline Cu_(2-x)Se film was epitaxial grown on(220)facets-exposed Cu by direct selenization of a nanoporous Cu skeleton,which is obtained by dealloying rolled Cu Mn@Cu alloy foil.Density functional theory calculation result shows strong adsorption energy for Se atoms on Cu(220)planes during selenization reaction,rendering a low energy consumption.By virtue of this core-shell 3D nanoporous architecture to offer abundant active sites and endow fast electron/ion transportation,the nanoporous Cu_(2-x)Se@Cu-0.15 composite electrode exhibits remarkable sodium-ion storage properties with high reversible capacity of 950.6μAh/cm^(2)at 50μA/cm^(2),suprior rate capability of 457.6μAh/cm^(2)at 500μA/cm^(2),as well as an ultra-long stability at a high current density.Mechanism investigation reveals that the electrochemical reaction is a typical conversion-type reaction with different intermediates.This novel electrode synthetic strategy provides useful instructions to design the high-performance anode material for sodium-ion batteries.展开更多
Laser mediated photothermal/chemodynamic co-therapy is widely applied for anti-cancer treatment due to its good therapeutic effect.However,the laser wavelength for effectively targeting deep tumor tissues can decide w...Laser mediated photothermal/chemodynamic co-therapy is widely applied for anti-cancer treatment due to its good therapeutic effect.However,the laser wavelength for effectively targeting deep tumor tissues can decide whether or not it is a key premise of irradiation treatment.In this study,a super-homogenous and highly dispersive spherical nanoparticle Cu_(2-x)Se was prepared,which displayed a strong surface plasmon resonance(SPR)peak in the near-infrared region(NIR)-Ⅱand high Fenton catalytic efficiency.The results of in vitro experiments showed that Cu_(2-x)Se nanoparticles exhibited high photothermal conversion efficiency under the excitation of NIR-Ⅱlaser irradiation,which significantly improved its ability to produce OH.In a tumor-bearing mouse model,the combination of Cu_(2-x)Se and photothermal/chemodynamic co-therapy guided by the real-time photoacoustic imaging in the NIR-Ⅱcould effectively inhibit tumor growth and exhibit good in vivo/in vitro biocompatibility.In summary,this Cu_(2-x)Se nanoparticle-based NIR-Ⅱlaser-mediated photothermal/chemodynamic co-therapy strategy is expected to provide a new option for the diagnosis and treatment of liver cancer.展开更多
Polycrystalline Cu_(2)Se bulk materials were synthesized by high-pressure and high-temperature(HPHT)technique.The effects of synthetic temperature and pressure on the thermoelectric properties of Cu_(2)Se materials we...Polycrystalline Cu_(2)Se bulk materials were synthesized by high-pressure and high-temperature(HPHT)technique.The effects of synthetic temperature and pressure on the thermoelectric properties of Cu_(2)Se materials were investigated.The results indicate that both synthetic temperature and pressure determine the microstructure and thermoelectric performance of Cu2Se compounds.The increase of synthetic temperature can effectively enhance the electrical conductivity and decrease the lattice thermal conductivity.A two-fold improvement in the power factor is obtained at synthetic temperature of 1000℃ compared to that obtained at room temperature.All b-Cu2Se samples exhibit low and temperatureindependent lattice thermal conductivity ranging from 0.3 to 0.5 Wm^(-1)K^(-1) due to the intrinsic superionic feature and the abundant lattice defects produced at high pressure.A maximum zT of 1.19 at 723 K was obtained for the sample synthesized at 3 GPa and 1000℃.These findings indicate that HPHT technology is an efficient approach to synthesize Cu_(2)Se-based bulk materials.展开更多
基金The Natural Science Foundation of Henan Province(222300420083)the Opening Foundation of State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resource of Xinjiang University(KFKT2021004)。
文摘The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical performance.Herein,metallic Cu_(2)Se encapsulated with N-doped carbon(Cu_(2)Se@NC)was prepared using Cu_(2)O nanocubes as templates through a combination of dopamine polymerization and hightemperature selenization.The unique nanocubic structure and uniform N-doped carbon coating could shorten the ion transport distance,accelerate electron/charge diffusion,and suppress volume variation,ultimately ensuring Cu_(2)Se@NC with excellent electrochemical performance in sodium ion batteries(SIBs)and potassium ion batteries(PIBs).The composite exhibited excellent rate performance(187.7 mA h g^(-1)at 50 A g^(-1)in SIBs and 179.4 mA h g^(-1)at 5 A g^(-1)in PIBs)and cyclic stability(246,8 mA h g^(-1)at 10 A g^(-1)in SIBs over 2500 cycles).The reaction mechanism of intercalation combined with conversion in both SIBs and PIBs was disclosed by in situ X-ray diffraction(XRD)and ex situ transmission electron microscope(TEM).In particular,the final products in PIBs of K_(2)Se and K_(2)Se_(3)species were determined after discharging,which is different from that in SIBs with the final species of Na_(2)Se.The density functional theory calculation showed that carbon induces strong coupling and charge interactions with Cu_(2)Se,leading to the introduction of built-in electric field on heterojunction to improve electron mobility.Significantly,the theoretical calculations discovered that the underlying cause for the relatively superior rate capability in SIBs to that in PIBs is the agile Na~+diffusion with low energy barrier and moderate adsorption energy.These findings offer theoretical support for in-depth understanding of the performance differences of Cu-based materials in different ion storage systems.
基金supported by the National Natural Science Foundation of China(51771072)the Outstanding Youth Scientist Foundation of Hunan Province(2020JJ2006)+2 种基金the Youth 1000 Talent Program of ChinaFundamental Research Funds for the Central UniversitiesHunan University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Independent Research Project(71860007)。
文摘The nanoporous Cu_(2-x)Se with Cu(Se-5%)surface catalysts were prepared through in situ dynamic restructuring strategy during the electrochemical process,which achieves highly selective electrochemical CO_(2) reduction to methanol.In situ and quasi-operando spectroscopic results provide a deep insight into the catalytic active centres of reconstructed heterogeneous catalysts for CO_(2) electroreduction.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772087,11904094,51972106,and 11804089)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)Natural Science Foundation of Hunan Province,China(Grant Nos.2019JJ50034 and 2019JJ50073).
文摘Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52271011,52102291,52101251)。
文摘Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architecture with a facile strategy is still challenging.Here we report that a polycrystalline Cu_(2-x)Se film was epitaxial grown on(220)facets-exposed Cu by direct selenization of a nanoporous Cu skeleton,which is obtained by dealloying rolled Cu Mn@Cu alloy foil.Density functional theory calculation result shows strong adsorption energy for Se atoms on Cu(220)planes during selenization reaction,rendering a low energy consumption.By virtue of this core-shell 3D nanoporous architecture to offer abundant active sites and endow fast electron/ion transportation,the nanoporous Cu_(2-x)Se@Cu-0.15 composite electrode exhibits remarkable sodium-ion storage properties with high reversible capacity of 950.6μAh/cm^(2)at 50μA/cm^(2),suprior rate capability of 457.6μAh/cm^(2)at 500μA/cm^(2),as well as an ultra-long stability at a high current density.Mechanism investigation reveals that the electrochemical reaction is a typical conversion-type reaction with different intermediates.This novel electrode synthetic strategy provides useful instructions to design the high-performance anode material for sodium-ion batteries.
基金supported by the project of"Ultra-small gold nanoparticles self-assembled by gadolinium ions and IR820 for liver cancer diagnosis and treatment"(No.2021YFSY0038).
文摘Laser mediated photothermal/chemodynamic co-therapy is widely applied for anti-cancer treatment due to its good therapeutic effect.However,the laser wavelength for effectively targeting deep tumor tissues can decide whether or not it is a key premise of irradiation treatment.In this study,a super-homogenous and highly dispersive spherical nanoparticle Cu_(2-x)Se was prepared,which displayed a strong surface plasmon resonance(SPR)peak in the near-infrared region(NIR)-Ⅱand high Fenton catalytic efficiency.The results of in vitro experiments showed that Cu_(2-x)Se nanoparticles exhibited high photothermal conversion efficiency under the excitation of NIR-Ⅱlaser irradiation,which significantly improved its ability to produce OH.In a tumor-bearing mouse model,the combination of Cu_(2-x)Se and photothermal/chemodynamic co-therapy guided by the real-time photoacoustic imaging in the NIR-Ⅱcould effectively inhibit tumor growth and exhibit good in vivo/in vitro biocompatibility.In summary,this Cu_(2-x)Se nanoparticle-based NIR-Ⅱlaser-mediated photothermal/chemodynamic co-therapy strategy is expected to provide a new option for the diagnosis and treatment of liver cancer.
基金the National Natural Science Foundation of China(No.11704340,11804305 and 51171070)the Project of Jilin Science and Technology Development Plan(Project No.20170101045JC)+1 种基金the China Postdoctoral Science Foundation(No.2017M620303 and 2017M622360)the Key Research Project of Higher Education Institution of Henan Province(No.19A140006).
文摘Polycrystalline Cu_(2)Se bulk materials were synthesized by high-pressure and high-temperature(HPHT)technique.The effects of synthetic temperature and pressure on the thermoelectric properties of Cu_(2)Se materials were investigated.The results indicate that both synthetic temperature and pressure determine the microstructure and thermoelectric performance of Cu2Se compounds.The increase of synthetic temperature can effectively enhance the electrical conductivity and decrease the lattice thermal conductivity.A two-fold improvement in the power factor is obtained at synthetic temperature of 1000℃ compared to that obtained at room temperature.All b-Cu2Se samples exhibit low and temperatureindependent lattice thermal conductivity ranging from 0.3 to 0.5 Wm^(-1)K^(-1) due to the intrinsic superionic feature and the abundant lattice defects produced at high pressure.A maximum zT of 1.19 at 723 K was obtained for the sample synthesized at 3 GPa and 1000℃.These findings indicate that HPHT technology is an efficient approach to synthesize Cu_(2)Se-based bulk materials.
