Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific c...Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific ca⁃pacity of MXene materials limit their further utilization.In this study,these issues are addressed using a heterostruc⁃ture strategy via a one-step selenization method to form Mo_(2)C@MoSe_(2).Synchrotron radiation X-ray spectroscopic and high-resolution transmission electron microscopy(HRTEM)characterizations revealed the heterostructure consisting of in-situ grown MoSe_(2)on Mo_(2)C MXene.Electrochemical tests proved the heterojunction electrode’s superior rate perfor⁃mance of 289.06 mAh·g^(-1)at a high current density of 5 A·g^(-1)and long cycling stability of 550 mAh·g^(-1)after 900 cycles at 1 A·g^(-1).This work highlights the useful X-ray spectroscopic analysis to directly elucidate the heterojunction structure,providing an effective reference method for probing heterostructures.展开更多
X-ray absorption fine structure (XAFS) has experienced a rapid development in the last three decades and has proven to be a powerful structural characterization technique nowadays. In this review, the XAFS basic princ...X-ray absorption fine structure (XAFS) has experienced a rapid development in the last three decades and has proven to be a powerful structural characterization technique nowadays. In this review, the XAFS basic principles including the theory, the data analysis, and the experiments have been introduced in detail. To show its strength as a local structure probe, the XAFS applications in semiconductors are summarized comprehensively, that is, thin films, quantum wells and dots, dilute magnetic semiconductors, and so on. In addition, certain new XAFS-related techniques, such as in-situ XAFS, micro-XAFS, and time-resolved XAFS are also shown.展开更多
Few-layer graphene(FLG)is successfully grown on sapphire substrates by directly depositing carbon atoms at the substrate temperature of 1300℃ in a molecular beam epitaxy chamber.The reflection high energy diffraction...Few-layer graphene(FLG)is successfully grown on sapphire substrates by directly depositing carbon atoms at the substrate temperature of 1300℃ in a molecular beam epitaxy chamber.The reflection high energy diffraction,Raman spectroscopy and near-edge x-ray absorption fine structure are used to characterize the sample,which confirm the formation of graphene layers.The mean domain size of FLG is around 29.2nm and the layer number is about 2–3.The results demonstrate that the grown FLG displays a turbostratic stacking structure similar to that of the FLG produced by annealing C-terminated𝛼α-SiC surface.展开更多
Local structures of the mechanically alloyed Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)soft magnetic materials have been in vestigated by x-ray absorption fine structure.The results show that mechanical alloying(MA)can dr...Local structures of the mechanically alloyed Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)soft magnetic materials have been in vestigated by x-ray absorption fine structure.The results show that mechanical alloying(MA)can drive theFe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)powder mixture to produce amorphous alloy when the atomic concentration of Fe ele ment is about and over 40%.On the contrary,the MA Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)is a solid solution with an fcc-like structure in the region of lower Fe atomic concentration(<22%),preserving a medium-range order around Ni and Fe atoms.Moreover,we have found that the local structure geometry of Fe atom is similar to that of Ni atom for all the MA Fer7-xNixCu1 Nb2P14B6 samples.It indicates that the local structures of Fe and Ni atoms in a Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)sample only depend on the x value of element Ni after ball milling.展开更多
基金National Key Research and Development Program of China(2020YFA0405800)National Natural Science Foundation of China(12322515,U23A20121,12225508)+2 种基金Youth Innovation Promotion Association of CAS(2022457)National Postdoctoral Program for Innovative Talents(BX20230346)China Postdoctoral Science Foundation(2023M743365)。
文摘Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific ca⁃pacity of MXene materials limit their further utilization.In this study,these issues are addressed using a heterostruc⁃ture strategy via a one-step selenization method to form Mo_(2)C@MoSe_(2).Synchrotron radiation X-ray spectroscopic and high-resolution transmission electron microscopy(HRTEM)characterizations revealed the heterostructure consisting of in-situ grown MoSe_(2)on Mo_(2)C MXene.Electrochemical tests proved the heterojunction electrode’s superior rate perfor⁃mance of 289.06 mAh·g^(-1)at a high current density of 5 A·g^(-1)and long cycling stability of 550 mAh·g^(-1)after 900 cycles at 1 A·g^(-1).This work highlights the useful X-ray spectroscopic analysis to directly elucidate the heterojunction structure,providing an effective reference method for probing heterostructures.
基金Supported by National Natural Science Foundation of China (Grant No. 10375059,10404023)the Cooperation Program between NSRL and BSRF+1 种基金the Innova-tion Program of Chinese Academy of Sciences Specialized Research Fund for the Doctoral Program of Higher Education.
文摘X-ray absorption fine structure (XAFS) has experienced a rapid development in the last three decades and has proven to be a powerful structural characterization technique nowadays. In this review, the XAFS basic principles including the theory, the data analysis, and the experiments have been introduced in detail. To show its strength as a local structure probe, the XAFS applications in semiconductors are summarized comprehensively, that is, thin films, quantum wells and dots, dilute magnetic semiconductors, and so on. In addition, certain new XAFS-related techniques, such as in-situ XAFS, micro-XAFS, and time-resolved XAFS are also shown.
基金by the National Natural Science Foundation of China under Grant No 50872128the Natural Science Foundation of Anhui Province(No 11040606M64)the Natural Science Foundation of Higher Education Institutions of Anhui Province(No KJ2010B189).
文摘Few-layer graphene(FLG)is successfully grown on sapphire substrates by directly depositing carbon atoms at the substrate temperature of 1300℃ in a molecular beam epitaxy chamber.The reflection high energy diffraction,Raman spectroscopy and near-edge x-ray absorption fine structure are used to characterize the sample,which confirm the formation of graphene layers.The mean domain size of FLG is around 29.2nm and the layer number is about 2–3.The results demonstrate that the grown FLG displays a turbostratic stacking structure similar to that of the FLG produced by annealing C-terminated𝛼α-SiC surface.
基金Supported by the"100 people plan"of Chinese Academy of Sciences,and the National Natural Science Foundation of China under Grant No.19604011.
文摘Local structures of the mechanically alloyed Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)soft magnetic materials have been in vestigated by x-ray absorption fine structure.The results show that mechanical alloying(MA)can drive theFe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)powder mixture to produce amorphous alloy when the atomic concentration of Fe ele ment is about and over 40%.On the contrary,the MA Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)is a solid solution with an fcc-like structure in the region of lower Fe atomic concentration(<22%),preserving a medium-range order around Ni and Fe atoms.Moreover,we have found that the local structure geometry of Fe atom is similar to that of Ni atom for all the MA Fer7-xNixCu1 Nb2P14B6 samples.It indicates that the local structures of Fe and Ni atoms in a Fe_(77-x)Ni_(x)Cu_(1)Nb_(2)P_(14)B_(6)sample only depend on the x value of element Ni after ball milling.
