Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=...Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=–O and–S)was designed.The CO_(2)RR catalytic performance was stud‐ied using well‐defined ab initio calculations.Our results show that the CO_(2) molecule can be more readily activated on TM@Ti_(2)CO_(2) than the TM@Ti_(2)CS_(2) surface.Bader charge analysis reveals that the Ti_(2)CO_(2) substrate is involved in the adsorption reaction,and enough electrons are injected into the 2π*u orbital of CO_(2),leading to a V‐shaped CO_(2) molecular configuration and partial negative charge distribution.The V‐shaped CO_(2) further reduces the difficulty of the first hydrogenation reac‐tion step.The calculatedΔG of the first hydrogenation reaction on TM@Ti_(2)CO_(2) was significantly lower than that of the TM@Ti_(2)CS_(2) counterpart.However,the subsequent CO_(2) reduction pathways show that the UL of the potential determining step on TM@Ti_(2)CS_(2) is smaller than that of TM@Ti_(2)CO_(2).Combining the advantages of both TM@Ti_(2)CS_(2) and TM@Ti_(2)CO_(2),we designed a mixed functional group surface with–O and–S to anchor TM atoms.The results show that Cr atoms an‐chored on the surface of mixed functional groups exhibit high catalytic activity for the selective production of CH4.This study opens an exciting new avenue for the rational design of highly selec‐tive MXene‐based single‐atom CO_(2)RR electrocatalysts.展开更多
We revisit the harmonic approximation (HA) for a large Josephson junction interacting with some charge qubits through the variational approach for the quantum dynamics of the junction-qubit coupling system. By making ...We revisit the harmonic approximation (HA) for a large Josephson junction interacting with some charge qubits through the variational approach for the quantum dynamics of the junction-qubit coupling system. By making use of numerical calculation and analytical treatment, the conditions under which HA works well can be precisely presented to control the parameters implementing the two-qubit quantum logical gate through the couplings to the large junction with harmonic oscillator Hamiltonian.展开更多
In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-...In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-pir orbitals that the ligand Mo3S44+ bonds to the M atom to form these class clusters. It is revealed that the charges transfer from the M atom to Mo atom of the ligand Mo3S44+ and its relationship with the MC (multiple center) d-pπ orbitals. Based on the charge transfer the electronic spectrum and the magnetic property of some cubane clusters have been discussed.展开更多
The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible re...The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible representations in momentum space.In this work,we define unconventional materials with a common feature of the mismatch between average electronic centers and atomic positions.They can be effectively diagnosed as whose occupied bands can be expressed as a sum of elementary BRs(eBRs),but not a sum of atomic-orbital-induced BRs(aBRs).The existence of an essential BR at an empty site is described by nonzero real-space invariants(RSIs).The"valence"states can be derived by the aBR decomposition,and unconventional materials are supposed to have an uncompensated total"valence"state.The high-throughput screening for unconventional materials has been performed through the first-principles calculations.We have discovered 423 unconventional compounds,including thermoelectronic materials,higher-order topological insulators,electrides,hydrogen storage materials,hydrogen evolution reaction electrocatalysts,electrodes,and superconductors.The diversity of these interesting properties and applications would be widely studied in the future.展开更多
文摘Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=–O and–S)was designed.The CO_(2)RR catalytic performance was stud‐ied using well‐defined ab initio calculations.Our results show that the CO_(2) molecule can be more readily activated on TM@Ti_(2)CO_(2) than the TM@Ti_(2)CS_(2) surface.Bader charge analysis reveals that the Ti_(2)CO_(2) substrate is involved in the adsorption reaction,and enough electrons are injected into the 2π*u orbital of CO_(2),leading to a V‐shaped CO_(2) molecular configuration and partial negative charge distribution.The V‐shaped CO_(2) further reduces the difficulty of the first hydrogenation reac‐tion step.The calculatedΔG of the first hydrogenation reaction on TM@Ti_(2)CO_(2) was significantly lower than that of the TM@Ti_(2)CS_(2) counterpart.However,the subsequent CO_(2) reduction pathways show that the UL of the potential determining step on TM@Ti_(2)CS_(2) is smaller than that of TM@Ti_(2)CO_(2).Combining the advantages of both TM@Ti_(2)CS_(2) and TM@Ti_(2)CO_(2),we designed a mixed functional group surface with–O and–S to anchor TM atoms.The results show that Cr atoms an‐chored on the surface of mixed functional groups exhibit high catalytic activity for the selective production of CH4.This study opens an exciting new avenue for the rational design of highly selec‐tive MXene‐based single‐atom CO_(2)RR electrocatalysts.
基金the Cooperation Foundation of Nankai University，Tianjin University for research of nanoscience，国家自然科学基金
文摘We revisit the harmonic approximation (HA) for a large Josephson junction interacting with some charge qubits through the variational approach for the quantum dynamics of the junction-qubit coupling system. By making use of numerical calculation and analytical treatment, the conditions under which HA works well can be precisely presented to control the parameters implementing the two-qubit quantum logical gate through the couplings to the large junction with harmonic oscillator Hamiltonian.
文摘In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-pir orbitals that the ligand Mo3S44+ bonds to the M atom to form these class clusters. It is revealed that the charges transfer from the M atom to Mo atom of the ligand Mo3S44+ and its relationship with the MC (multiple center) d-pπ orbitals. Based on the charge transfer the electronic spectrum and the magnetic property of some cubane clusters have been discussed.
基金supported by the National Natural Science Foundation of China(11974395 and 12188101)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB33000000)+6 种基金the Center for Materials Genomesupport from the Ministry of Science and Technology of China under Grant Nos.2016YFA0300600 and 2018YFA0305700the Chinese Academy of Sciences under Grant No.XDB28000000the Science Challenge Project(TZ2016004)the K.C.Wong Education Foundation(GJTD-2018-01)Beijing Municipal Science&Technology Commission(Z181100004218001)Beijing Natural Science Foundation(Z180008)。
文摘The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible representations in momentum space.In this work,we define unconventional materials with a common feature of the mismatch between average electronic centers and atomic positions.They can be effectively diagnosed as whose occupied bands can be expressed as a sum of elementary BRs(eBRs),but not a sum of atomic-orbital-induced BRs(aBRs).The existence of an essential BR at an empty site is described by nonzero real-space invariants(RSIs).The"valence"states can be derived by the aBR decomposition,and unconventional materials are supposed to have an uncompensated total"valence"state.The high-throughput screening for unconventional materials has been performed through the first-principles calculations.We have discovered 423 unconventional compounds,including thermoelectronic materials,higher-order topological insulators,electrides,hydrogen storage materials,hydrogen evolution reaction electrocatalysts,electrodes,and superconductors.The diversity of these interesting properties and applications would be widely studied in the future.
