Sodium(Na)O_(2)batteries have high energy density and low cost.However,high polarization,complex discharge products,and low Coulombic efficiency(CE)lead to poor cyclability.Here,we proposed an atomically dispersed Ru ...Sodium(Na)O_(2)batteries have high energy density and low cost.However,high polarization,complex discharge products,and low Coulombic efficiency(CE)lead to poor cyclability.Here,we proposed an atomically dispersed Ru catalyst on nitrogen-doped graphene for Na-O_(2)batteries.The catalysts enable the discharge to proceed via a surface-mediated route,which leads to uniform deposition of Na_(2-x)O_(2)and low polarization during recharge.The first-principle calculation revealed that Ru-N_(4)complex in the catalyst has strong chemical adsorption to intermediate superoxides,facilitating uniform deposition and enhancing rapid kinetics.In contrast,Ru nanoparticles,despite the catalytic activity,induce bulk deposition via a solution-mediated route because the exposed graphene surface shows weak interaction to superoxides,thereby lowering CEs and cyclability.In brief,the atomically-dispersed Ru catalyst endows Na-O_(2)batteries with excellent electrochemical properties via a surface-mediated discharge.展开更多
Huntington's disease(HD)is caused by the abnormal expansion of polyglutamine(poly Q)repeats encoded in exon 1 of the huntingtin(HTT)gene,with neurotoxicity typically emerging when the repeat length exceeds 36 glut...Huntington's disease(HD)is caused by the abnormal expansion of polyglutamine(poly Q)repeats encoded in exon 1 of the huntingtin(HTT)gene,with neurotoxicity typically emerging when the repeat length exceeds 36 glutamine residues.Increasing the poly Q length promotes hypercompact conformations;however,how such compact chains mechanically unfold under nanoconfinement remains insufficiently understood.In this study,all-atom molecular dynamics simulations were performed to investigate the nanopore transport and surface-induced unfolding of poly Q chains of different lengths(Q22,Q36,Q40,and Q46)through graphene nanopores under controlled pulling velocities.By quantitatively analyzing the transport dynamics,as characterized by the pulling force,radius of gyration,center-of-mass distance,interaction energies,number of transported residues,and pulling energy,we demonstrated that poly Q chains of all investigated lengths can successfully translocate through the nanopore and undergo progressive unfolding on the graphene surface over a wide range of pulling velocities.Longer poly Q chains exhibit a higher resistance to unfolding,characterized by enhanced force peaks and increased pulling energy,reflecting stronger intramolecular interactions.Moreover,slower pulling velocities reduce the force fluctuations and lower the overall pulling energy.These results provide molecular-level mechanistic insights into the length-dependent transport and surface-mediated unfolding of poly Q,offering a physical basis for understanding poly Q conformational regulation relevant to Huntington's disease.展开更多
High selectivity toward alkenes in oxidative dehydrogenation(ODH)of light alkanes makes boron-based materials promising Catalysts.However,many key mechanistic aspects are still debated due to the challenge of capturin...High selectivity toward alkenes in oxidative dehydrogenation(ODH)of light alkanes makes boron-based materials promising Catalysts.However,many key mechanistic aspects are still debated due to the challenge of capturing fleeting reaction intermediates.Kinetic analysis,including determining reaction orders and activation energy,could be informative for reactions involving radical intermediates but has not been extensively exploited.This Review summarizes the current understanding of the apparent alkane reaction order and the apparent activation energy in the boron-catalyzed ODH.Despite varying compositions and structures,a majority of boron-based catalysts share many common features,induding alkene selectivity,the evolution and the formation of active site,and the apparent kinetic properties.These common trends could be attributed to the shared gas-phase radical mediated reaction pathways and the formation of active hydroxylated boron oxide species on boron-containing materials under ODH conditions.Values of apparent alkane reaction orders and apparent activation energies are sensitive and reliable experimental measures of the contributions of the gas-phase radical-mediated and surface mediated pathways,suggesting the outline of a general mechanistic framework of the boron-catalyzed ODH.展开更多
基金the financial support of the National Natural Science Foundation of China(Nos.22075131,21776121)National Key R&D Program of China(No.2020YFA0406104)。
文摘Sodium(Na)O_(2)batteries have high energy density and low cost.However,high polarization,complex discharge products,and low Coulombic efficiency(CE)lead to poor cyclability.Here,we proposed an atomically dispersed Ru catalyst on nitrogen-doped graphene for Na-O_(2)batteries.The catalysts enable the discharge to proceed via a surface-mediated route,which leads to uniform deposition of Na_(2-x)O_(2)and low polarization during recharge.The first-principle calculation revealed that Ru-N_(4)complex in the catalyst has strong chemical adsorption to intermediate superoxides,facilitating uniform deposition and enhancing rapid kinetics.In contrast,Ru nanoparticles,despite the catalytic activity,induce bulk deposition via a solution-mediated route because the exposed graphene surface shows weak interaction to superoxides,thereby lowering CEs and cyclability.In brief,the atomically-dispersed Ru catalyst endows Na-O_(2)batteries with excellent electrochemical properties via a surface-mediated discharge.
基金supported by the National Natural Science Foundation of China(Nos.12302408,20904047 and62375245)the Natural Science Foundation of Zhejiang Province(Nos.LY17A040001 and LY19F03004)+1 种基金the ZUST Postgraduate Course Development Fund(No.2025yjskj05)the ZUST Postgraduate Research and Innovation Fund(No.2025yjskc20)。
文摘Huntington's disease(HD)is caused by the abnormal expansion of polyglutamine(poly Q)repeats encoded in exon 1 of the huntingtin(HTT)gene,with neurotoxicity typically emerging when the repeat length exceeds 36 glutamine residues.Increasing the poly Q length promotes hypercompact conformations;however,how such compact chains mechanically unfold under nanoconfinement remains insufficiently understood.In this study,all-atom molecular dynamics simulations were performed to investigate the nanopore transport and surface-induced unfolding of poly Q chains of different lengths(Q22,Q36,Q40,and Q46)through graphene nanopores under controlled pulling velocities.By quantitatively analyzing the transport dynamics,as characterized by the pulling force,radius of gyration,center-of-mass distance,interaction energies,number of transported residues,and pulling energy,we demonstrated that poly Q chains of all investigated lengths can successfully translocate through the nanopore and undergo progressive unfolding on the graphene surface over a wide range of pulling velocities.Longer poly Q chains exhibit a higher resistance to unfolding,characterized by enhanced force peaks and increased pulling energy,reflecting stronger intramolecular interactions.Moreover,slower pulling velocities reduce the force fluctuations and lower the overall pulling energy.These results provide molecular-level mechanistic insights into the length-dependent transport and surface-mediated unfolding of poly Q,offering a physical basis for understanding poly Q conformational regulation relevant to Huntington's disease.
基金National Natural Science Foundation of China(22172001 and 22108006)Beijing National Laboratory for Molecular Sciences.
文摘High selectivity toward alkenes in oxidative dehydrogenation(ODH)of light alkanes makes boron-based materials promising Catalysts.However,many key mechanistic aspects are still debated due to the challenge of capturing fleeting reaction intermediates.Kinetic analysis,including determining reaction orders and activation energy,could be informative for reactions involving radical intermediates but has not been extensively exploited.This Review summarizes the current understanding of the apparent alkane reaction order and the apparent activation energy in the boron-catalyzed ODH.Despite varying compositions and structures,a majority of boron-based catalysts share many common features,induding alkene selectivity,the evolution and the formation of active site,and the apparent kinetic properties.These common trends could be attributed to the shared gas-phase radical mediated reaction pathways and the formation of active hydroxylated boron oxide species on boron-containing materials under ODH conditions.Values of apparent alkane reaction orders and apparent activation energies are sensitive and reliable experimental measures of the contributions of the gas-phase radical-mediated and surface mediated pathways,suggesting the outline of a general mechanistic framework of the boron-catalyzed ODH.
