Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etchin...Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etching of MoAlB has not been very successful.It has been proposed that the 2D MoB MBene may be fabricated by chemical etching of a Mo_(2)AlB_(2) precursor,but further investigations were not performed possibly due to the difficult preparation of the metastable Mo_(2)AlB_(2) compound at high temperatures by solid-state reactions.Here,we report on the successful synthesis of the Mo_(2)AlB_(2) compound and 2D MoB nanosheets by the deintercalation of Al from MoAlB through a ZnCl_(2) molten salt etching approach at relatively low temperatures.The influence of etching temperature,etching time,and starting mixtures on the formation of desirable phases have been investigated.A pure Mo_(2)AlB_(2) compound was synthesized at temperatures below 600℃,while the 2D MoB MBene nanosheets were obtained at 700℃through the molten salt etching of MoAlB.In addition,the present work further confirms that the MoB MBene can be prepared by etching the as-synthesized Mo_(2)AlB_(2) precursor in LiF–HCl solution.Our work demonstrates that the molten salt etching is an effective method to prepare 2D MoB MBene.展开更多
Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect...Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect their physical properties.In this study,a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed.The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)C.On the basis of this mechanism,the room-temperature ferromagnetism of two-dimensional few-layered Cr_(2)CT_(x)MXenes,which has a specific saturation magnetization of~0.26 emu/g and a Curie temperature of>353 K,is experimentally verified.The calculated electronic band structure implies that the semimetal Cr_(2)CT_(x)MXene has a band gap of 0.75 eV.This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2022YJS088)the National Natural Science Foundation of China(Grant No.52275171).
文摘Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etching of MoAlB has not been very successful.It has been proposed that the 2D MoB MBene may be fabricated by chemical etching of a Mo_(2)AlB_(2) precursor,but further investigations were not performed possibly due to the difficult preparation of the metastable Mo_(2)AlB_(2) compound at high temperatures by solid-state reactions.Here,we report on the successful synthesis of the Mo_(2)AlB_(2) compound and 2D MoB nanosheets by the deintercalation of Al from MoAlB through a ZnCl_(2) molten salt etching approach at relatively low temperatures.The influence of etching temperature,etching time,and starting mixtures on the formation of desirable phases have been investigated.A pure Mo_(2)AlB_(2) compound was synthesized at temperatures below 600℃,while the 2D MoB MBene nanosheets were obtained at 700℃through the molten salt etching of MoAlB.In addition,the present work further confirms that the MoB MBene can be prepared by etching the as-synthesized Mo_(2)AlB_(2) precursor in LiF–HCl solution.Our work demonstrates that the molten salt etching is an effective method to prepare 2D MoB MBene.
基金supported financially by the Beijing Natural Science Foundation(Nos.2212046,2234093,and L211001)the National Natural Science Foundation of China(Nos.51871011 and 51572017)+1 种基金the Research Fund for Commercialization of Major Scientific and Technological Achievements of Hebei Province(No.22281006Z)the Beijing Government Funds for the Constructive Project of Central Universities.
文摘Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their stability.However,MXenes fabricated via acid etching contain defects,which affect their physical properties.In this study,a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed.The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)C.On the basis of this mechanism,the room-temperature ferromagnetism of two-dimensional few-layered Cr_(2)CT_(x)MXenes,which has a specific saturation magnetization of~0.26 emu/g and a Curie temperature of>353 K,is experimentally verified.The calculated electronic band structure implies that the semimetal Cr_(2)CT_(x)MXene has a band gap of 0.75 eV.This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.
