Freestanding honeycomb borophene is unstable due to the electron-deficiency of boron atoms. B_2H_2 monolayer, a typical borophene hydride, has been predicted to be structurally stable and attracts great attention. Her...Freestanding honeycomb borophene is unstable due to the electron-deficiency of boron atoms. B_2H_2 monolayer, a typical borophene hydride, has been predicted to be structurally stable and attracts great attention. Here, we investigate the electronic structures of B_2H_2 nanoribbons. Based on first-principles calculations, we have found that all narrow armchair nanoribbons with and without mirror symmetry(ANR-s and ANR-as, respectively) are semiconducting. The energy gap has a relation with the width of the ribbon. When the ribbon is getting wider, the gap disappears. The zigzag ribbons without mirror symmetry(ZNR-as) have the same trend. But the zigzag ribbons with mirror symmetry(ZNR-s) are always metallic. We have also found that the metallic ANR-as and ZNR-s can be switched to semiconducting by applying a tensile strain along the nanoribbon. A gap of 1.10 eV is opened under 16% strain for the 11.0-■ ANR-as. Structural stability under such a large strain has also been confirmed. The flexible band tunability of B_2H_2 nanoribbon increases its possibility of potential applications in nanodevices.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted considerable attention because of their unique properties and great potential in nano-technology applications.Great efforts have been devoted to ...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted considerable attention because of their unique properties and great potential in nano-technology applications.Great efforts have been devoted to fabrication of novel structured TMD monolayers by modifying their pristine structures at the atomic level.Here we propose an intriguing structured 1T-PtTe2 monolayer as hydrogen evolution reaction(HER)catalyst,namely,Pt4Te7,using first-principles calculations.It is found that Pt4Te7 is a stable monolayer material verified by the calculation of formation energy,phonon dispersion,and ab initio molecular dynamics simulations.Remarkably,the novel structured void-containing monolayer exhibits superior catalytic activity toward HER compared with the pristine one,with a Gibbs free energy very close to zero(less than 0.07 eV).These features indicate that Pt4Te7 monolayer is a high-performance HER catalyst with a high platinum utilization.These findings open new perspectives for the functionalization of 2D TMD materials at an atomic level and its application in HER catalysis.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61888102,61390501,and 51872284)the CAS Pioneer Hundred Talents Program+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)the Beijing Nova Program,China(Grant No.Z181100006218023)the University of Chinese Academy of Sciences
文摘Freestanding honeycomb borophene is unstable due to the electron-deficiency of boron atoms. B_2H_2 monolayer, a typical borophene hydride, has been predicted to be structurally stable and attracts great attention. Here, we investigate the electronic structures of B_2H_2 nanoribbons. Based on first-principles calculations, we have found that all narrow armchair nanoribbons with and without mirror symmetry(ANR-s and ANR-as, respectively) are semiconducting. The energy gap has a relation with the width of the ribbon. When the ribbon is getting wider, the gap disappears. The zigzag ribbons without mirror symmetry(ZNR-as) have the same trend. But the zigzag ribbons with mirror symmetry(ZNR-s) are always metallic. We have also found that the metallic ANR-as and ZNR-s can be switched to semiconducting by applying a tensile strain along the nanoribbon. A gap of 1.10 eV is opened under 16% strain for the 11.0-■ ANR-as. Structural stability under such a large strain has also been confirmed. The flexible band tunability of B_2H_2 nanoribbon increases its possibility of potential applications in nanodevices.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFA0202300,2018YFA0305800,and 2019YFA0308500)the National Natural Science Foundation of China(Grant Nos.61888102,51872284,and 51922011)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted considerable attention because of their unique properties and great potential in nano-technology applications.Great efforts have been devoted to fabrication of novel structured TMD monolayers by modifying their pristine structures at the atomic level.Here we propose an intriguing structured 1T-PtTe2 monolayer as hydrogen evolution reaction(HER)catalyst,namely,Pt4Te7,using first-principles calculations.It is found that Pt4Te7 is a stable monolayer material verified by the calculation of formation energy,phonon dispersion,and ab initio molecular dynamics simulations.Remarkably,the novel structured void-containing monolayer exhibits superior catalytic activity toward HER compared with the pristine one,with a Gibbs free energy very close to zero(less than 0.07 eV).These features indicate that Pt4Te7 monolayer is a high-performance HER catalyst with a high platinum utilization.These findings open new perspectives for the functionalization of 2D TMD materials at an atomic level and its application in HER catalysis.
