Single-atom catalysts(SACs)are gaining increasing recognition because of their superior catalytic properties for various reactions.However,the performance of SACs is often limited by the lack of neighboring metal cent...Single-atom catalysts(SACs)are gaining increasing recognition because of their superior catalytic properties for various reactions.However,the performance of SACs is often limited by the lack of neighboring metal centers to cooperate in catalysis.Herein,a synergetic interaction between neighboring Cu atoms of a few-atom catalyst(FAC)on graphdiyne(GDY)is found to greatly enhance the production of acetate in the CO electroreduction reaction relative to Cu SACs.In a 1.0 M KOH electrolyte,this Cu FAC exhibits an acetate Faradaic efficiency of 53.8±1.5%,an ultrahigh relative purity of up to 97 wt%for liquid products,and excellent stability over 23 h continuous electrolysis at–0.8 V versus reversible hydrogen electrode.Theoretical studies suggest that the intersite catalytic communication between two neighboring metal atoms confined in each pore of GDY facilitates the formation of acetic acid through either stepwise hydrogenation of CH_(2)CO^(*)or the direct reaction of H_(2)Owith CH_(2)CO^(*).Our study demonstrates the unprecedented synergetic catalysis of Cu FAC in promoting the selective CO electroreduction toward acetate production.展开更多
A new general formalism for determining the electric multipole polarizabilities of quantum (atomic and nuclear) bound systems based on the use of the transition matrix in momentum space has been developed. As distinct...A new general formalism for determining the electric multipole polarizabilities of quantum (atomic and nuclear) bound systems based on the use of the transition matrix in momentum space has been developed. As distinct from the conventional approach with the application of the spectral expansion of the total Green’s function, our approach does not require preliminary determination of the entire unperturbated spectrum;instead, it makes possible to calculate the polarizability of a few-body bound complex directly based on solving integral equations for the wave function of the ground bound state and the transition matrix at negative energy, both of them being real functions of momenta. A formula for the multipole polarizabilities of a two-body bound complex formed by a central interaction potential has been derived and studied. To test, the developed t-matrix formalism has been applied to the calculation of the dipole, quadrupole and octupole polarizabilities of the hydrogen atom.展开更多
基金supported by the National Natural Science Foundation of China(grant nos.21771098,21903016,and 21901110)Shenzhen R&D Fund(grant no.KQTD20180411143418361)+2 种基金Stable Support Plan Program of Shenzhen Natural Science Fund(grant no.20200925152742003)and Educational Commission of Guangdong Province(grant no.2020KTSCX121)S.T.and E.H.are supported by the Assistant Secretary for Energy Efficiency and Renewable Energy,Vehicle Technology Office of the US Department of Energy(DOE)through the Advanced Battery Materials Research(BMR)Program under contract no.DE-SC0012704.
文摘Single-atom catalysts(SACs)are gaining increasing recognition because of their superior catalytic properties for various reactions.However,the performance of SACs is often limited by the lack of neighboring metal centers to cooperate in catalysis.Herein,a synergetic interaction between neighboring Cu atoms of a few-atom catalyst(FAC)on graphdiyne(GDY)is found to greatly enhance the production of acetate in the CO electroreduction reaction relative to Cu SACs.In a 1.0 M KOH electrolyte,this Cu FAC exhibits an acetate Faradaic efficiency of 53.8±1.5%,an ultrahigh relative purity of up to 97 wt%for liquid products,and excellent stability over 23 h continuous electrolysis at–0.8 V versus reversible hydrogen electrode.Theoretical studies suggest that the intersite catalytic communication between two neighboring metal atoms confined in each pore of GDY facilitates the formation of acetic acid through either stepwise hydrogenation of CH_(2)CO^(*)or the direct reaction of H_(2)Owith CH_(2)CO^(*).Our study demonstrates the unprecedented synergetic catalysis of Cu FAC in promoting the selective CO electroreduction toward acetate production.
文摘A new general formalism for determining the electric multipole polarizabilities of quantum (atomic and nuclear) bound systems based on the use of the transition matrix in momentum space has been developed. As distinct from the conventional approach with the application of the spectral expansion of the total Green’s function, our approach does not require preliminary determination of the entire unperturbated spectrum;instead, it makes possible to calculate the polarizability of a few-body bound complex directly based on solving integral equations for the wave function of the ground bound state and the transition matrix at negative energy, both of them being real functions of momenta. A formula for the multipole polarizabilities of a two-body bound complex formed by a central interaction potential has been derived and studied. To test, the developed t-matrix formalism has been applied to the calculation of the dipole, quadrupole and octupole polarizabilities of the hydrogen atom.
文摘本文实验测量了少周期飞秒激光场下惰性气体Ne原子非顺序双电离引起的Ne^(2+)离子动量分布,发现该分布强烈依赖于激光场的载波-包络相位(Carrier-Envelope Phase,CEP),在某些CEP条件下呈现出明显不对称的双峰结构.半经典理论计算可以定性地重现实验结果.理论分析表明,二价离子的不对称动量分布来自于非顺序双电离过程中碰撞直接电离(Recollision-Impact-Ionization,RII)与碰撞-激发电离(Recollision-Excitation and Subsequent Ionization,RESI)两个通道的贡献,其中不对称双峰结构来自于RII通道,而RESI通道影响的是低动量部分,导致双峰结构变平.RII通道中产生的Ne^(2+)离子动量分布对CEP有较强的依赖性,而RESI通道中Ne^(2+)离子动量分布随CEP的变化不明显.进一步的计算表明,离子实库仑势在非顺序双电离过程中起到非常重要的作用,它将引起RESI通道产量增大.
