In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge eff...In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge efficiency and the overall longevity of the battery.Herein,a novel two-dimensional Ti_(3)C_(2) fragments enmeshed on iron-nitrogen-carbon(Fe-N-C)nanosheets(Ti_(3)C_(2)/Fe-NC)has been synthesized.This electrode features a matrix which has been shown to expedite SEI layer formation through the facilitation of selective anion adsorption,thus augmenting battery performance.Density functional theory calculation reveals that the SEI evolution energy of NaPF6 at the Ti_(3)C_(2)/Fe-N-C interface is 0.81 eV,significantly lower than the Ti_(3)C_(2)(1.23 eV).This process is driven by the electron transportation from Ti_(3)C_(2) to Fe-N-C substrate,facilitated by their work-function difference,leading to the formation of ferromagnetic Fe species,which possesses Fe 3d d_(xz)d_(z)2 orbitals and undergoes hybridization with theπandσorbitals of NaF,creating a key intermediate during charging.This process diminishes the antibonding energy and attenuates the orbital interaction with NaF,thus reducing the activation energy and improving the SEI formation reaction kinetics.Consequently,it leads to the creation of multi-interface SEI characterized by high-throughput ion transport and an efficient reaction network.展开更多
In Fenton-like reactions,high-valent cobalt-oxo(Co^(IV)=O)has attracted increasing interests due to high redox potential,long lifetime,and anti-interference properties,but its generation is hindered by the electron re...In Fenton-like reactions,high-valent cobalt-oxo(Co^(IV)=O)has attracted increasing interests due to high redox potential,long lifetime,and anti-interference properties,but its generation is hindered by the electron repulsion between the electron rich oxo-and cobalt centers.Here,we demonstrate Co^(IV)=O generation from peroxymonosulfate(PMS)activation over cobalt single-atom catalysts(Co-SACs)using in-situ Co K-edge X-ray absorption spectra,and discern that Co^(IV)=O generation is dependent on the support work-function(WF)due to the strong electronic metal-support interaction(EMSI).Supports with a high WF value like anatase-TiO_(2)facilitate the binding of PMS-terminal oxo-ligand to Co sites by extracting Cod electrons,thus decreasing the generation barrier for the critical intermediate(Co-OOSO_(3)^(2-)).The Co atoms anchored on anatase-TiO_(2)(Co-TiO_(2))exhibited enhanced Co^(IV)=O generation and superior activity for sulfamethoxazole(SMX)degradation during PMS activation.The normalized steady-state concentration of Co^(IV)=O in Co-TiO_(2)/PMS system was three orders of magnitude higher than that of free radicals,and 1.3-to 11-fold higher than that generated in other Co-SACs/PMS systems.Co-TiO_(2)/PMS sustained efficient removal of SMX with minimal Co^(2+)leaching under continuous flow operation,suggesting its attractive water purification potential.Overall,these results underscore the significance of support selection for enhanced generation of high-valent metal-oxo species and efficient PMS activation in supported metal SACs.展开更多
We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. ...We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. In this paper, the effective work function of EWF ranges from 4.22 to 4.56 eV with different thicknesses of TiN and TaN. The thinner TiN and/or thinner in situ TaN capping, the closer to conduction band of silicon the EWF is, which is appropriate for 2-D planar NMOS. Mid-gap work function behavior is observed with thicker TiN, thicker in situ TaN capping, indicating a strong potential candidate of metal gate material for replacement gate processed three-dimensional devices such as FIN shaped field effect transistors. The physical understandings of the sensitivity of EWF to TiN and TaN thickness are proposed. The thicker TiN prevents the A1 diffusion then induces the EWF to shift to mid-gap. However, the TaN plays a different role in effective work function tuning from TiN, due to the Ta-O dipoles formed at the interface between the metal gate and the high-k layer.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U22A20107,22162026,and 42050203)the Science and Technology Research and Develpoment Program Joint Fund Project of Henan Provincial(No.222301420001)+3 种基金the Distinguished Young Scholars Innovation Team of Zhengzhou University(No.32320275)Key Research Projects of University in Henan Province(No.24A150041)Henan Province Science and Technology Research Projects(No.242102240106)Postdoctoral Fellowship Program of CPSF(No.GZC20232382).
文摘In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge efficiency and the overall longevity of the battery.Herein,a novel two-dimensional Ti_(3)C_(2) fragments enmeshed on iron-nitrogen-carbon(Fe-N-C)nanosheets(Ti_(3)C_(2)/Fe-NC)has been synthesized.This electrode features a matrix which has been shown to expedite SEI layer formation through the facilitation of selective anion adsorption,thus augmenting battery performance.Density functional theory calculation reveals that the SEI evolution energy of NaPF6 at the Ti_(3)C_(2)/Fe-N-C interface is 0.81 eV,significantly lower than the Ti_(3)C_(2)(1.23 eV).This process is driven by the electron transportation from Ti_(3)C_(2) to Fe-N-C substrate,facilitated by their work-function difference,leading to the formation of ferromagnetic Fe species,which possesses Fe 3d d_(xz)d_(z)2 orbitals and undergoes hybridization with theπandσorbitals of NaF,creating a key intermediate during charging.This process diminishes the antibonding energy and attenuates the orbital interaction with NaF,thus reducing the activation energy and improving the SEI formation reaction kinetics.Consequently,it leads to the creation of multi-interface SEI characterized by high-throughput ion transport and an efficient reaction network.
基金supported by the National Natural Science Foundation of China(22376138 and 52070128)the National Key R&D Program of China(2023YFC3708005)National Science Foundation Engineering Research Centers on Nanotechnology-Enabled Water Treatment(EEC-1449500)。
文摘In Fenton-like reactions,high-valent cobalt-oxo(Co^(IV)=O)has attracted increasing interests due to high redox potential,long lifetime,and anti-interference properties,but its generation is hindered by the electron repulsion between the electron rich oxo-and cobalt centers.Here,we demonstrate Co^(IV)=O generation from peroxymonosulfate(PMS)activation over cobalt single-atom catalysts(Co-SACs)using in-situ Co K-edge X-ray absorption spectra,and discern that Co^(IV)=O generation is dependent on the support work-function(WF)due to the strong electronic metal-support interaction(EMSI).Supports with a high WF value like anatase-TiO_(2)facilitate the binding of PMS-terminal oxo-ligand to Co sites by extracting Cod electrons,thus decreasing the generation barrier for the critical intermediate(Co-OOSO_(3)^(2-)).The Co atoms anchored on anatase-TiO_(2)(Co-TiO_(2))exhibited enhanced Co^(IV)=O generation and superior activity for sulfamethoxazole(SMX)degradation during PMS activation.The normalized steady-state concentration of Co^(IV)=O in Co-TiO_(2)/PMS system was three orders of magnitude higher than that of free radicals,and 1.3-to 11-fold higher than that generated in other Co-SACs/PMS systems.Co-TiO_(2)/PMS sustained efficient removal of SMX with minimal Co^(2+)leaching under continuous flow operation,suggesting its attractive water purification potential.Overall,these results underscore the significance of support selection for enhanced generation of high-valent metal-oxo species and efficient PMS activation in supported metal SACs.
基金Project supported by the Important National Science & Technology Specific Projects(No.2009ZX02035)the National Natural Science Foundation of China(Nos.61176091,61306129)
文摘We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. In this paper, the effective work function of EWF ranges from 4.22 to 4.56 eV with different thicknesses of TiN and TaN. The thinner TiN and/or thinner in situ TaN capping, the closer to conduction band of silicon the EWF is, which is appropriate for 2-D planar NMOS. Mid-gap work function behavior is observed with thicker TiN, thicker in situ TaN capping, indicating a strong potential candidate of metal gate material for replacement gate processed three-dimensional devices such as FIN shaped field effect transistors. The physical understandings of the sensitivity of EWF to TiN and TaN thickness are proposed. The thicker TiN prevents the A1 diffusion then induces the EWF to shift to mid-gap. However, the TaN plays a different role in effective work function tuning from TiN, due to the Ta-O dipoles formed at the interface between the metal gate and the high-k layer.
