Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable ...Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable energy conversion.In this regard,meticulous design of active sites and probing their catalytic mechanism on both cathode and anode with different reaction environment at molecular-scale are vitally necessary.Herein,a coordination environment inheriting strategy is presented for designing low-coordination Ni^(2+)octahedra(L-Ni-8)atomic interface at a high concentration(4.6 at.%).Advanced spectroscopic techniques and theoretical calculations reveal that the self-matching electron delocalization and localization state at L-Ni-8 atomic interface enable an ideal reaction environment at both cathode and anode.To improve the efficiency of using the self-modification reaction environment at L-Ni-8,all of the structural features,including high atom economy,mass transfer,and electron transfer,are integrated together from atomic-scale to macro-scale.At high current density of 500 mA/cm2,the samples synthesized at gram-scale can deliver low hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of 262 and 348 mV,respectively.展开更多
Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte inte...Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte interface and on the resultant mass transport within the hydrodynamic boundary layer in the vicinity of the cathode.To resolve the complex local reaction environment of branching CO_(2)reduction pathways,we here present a dif-ferential electrochemical mass spectroscopic(DEMS)approach for Cu electrodes to investigate CO_(2)mass trans-port,the local concentration gradients of buffering anions,and the Cu surface topology effects on CO_(2)electrolysis selectivity at a temporal resolution of~400 ms.As a proof of concept,these tuning knobs were validated on an anion exchange membrane electrolyzer,which delivered a Faradaic efficiency of up to 40.4%and a partial current density of 121 mA cm^(-2)for CO_(2)-to-C_(2)H_(4)valorization.This methodology,which bridges the study of fundamental surface electrochemistry and the upgrading of practical electrolyzer performance,could be of general interest in helping to achieve a sustainable circular carbon economy.展开更多
Precisely designing atomic metal-nitrogen-carbon(M-N-C)catalysts with asymmetric diatomic configurations and studying their structure–activity relationships for oxygen reduction reaction(ORR)are important for zinc-ai...Precisely designing atomic metal-nitrogen-carbon(M-N-C)catalysts with asymmetric diatomic configurations and studying their structure–activity relationships for oxygen reduction reaction(ORR)are important for zinc-air batteries(ZABs).Herein,a dualatomic-site catalyst(DASC)with CoN_(3)S-MnN_(2)S_(2) configuration was prepared for the cathodes of ZABs.Compared with Co-N-C(Mn-free)and CoMn-N-C(S-free doping),CoMn-N/S-C exhibits excellent half-wave potential(0.883 V)and turnover frequency(1.54 e·s^(−1)·site^(−1)),surpassing most of the reported state-of-the-art Pt-free ORR catalysts.The CoMn-N/S-C-based ZABs achieve extremely high specific capacity(959 mAh·g^(−1))and good stability(350 h@5 mA·cm^(−2)).Density functional theory(DFT)calculation shows that the introduction of Mn and S can break the electron configuration symmetry of the original Co 3d orbital,lower the dband center of the Co site,and optimize the desorption behavior of*OH intermediate,thereby increasing the ORR activity.展开更多
Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so sm...Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so small(i.e.,τ→0)that it could be eliminated adiabatically.Nevertheless,whether the chimera states still exist in the opposite situation(i.e.,τ≫1)is unknown.Here,by coupling large populations of Stuart–Landau oscillators to a diffusive environment,we demonstrate that spiral wave chimeras do exist in this oscillator-environment coupling system even whenτis very large.Various transitions such as from spiral wave chimeras to spiral waves or unstable spiral wave chimeras as functions of the system parameters are explored.A physical picture for explaining the formation of spiral wave chimeras is also provided.The existence of spiral wave chimeras is further confirmed in ensembles of FitzHugh–Nagumo oscillators with the similar oscillator-environment coupling mechanism.Our results provide an affirmative answer to the observation of spiral wave chimeras in populations of oscillators mediated via a slowly changing environment and give important hints to generate chimera patterns in both laboratory and realistic chemical or biological systems.展开更多
Carbon-based N-coordinated Mn(Mn-N_(x)/C)single-atom electrocatalysts are considered as one of the most desirable non-precious oxygen reduction reaction(ORR)candidates due to their insignificant Fenton reactivity,high...Carbon-based N-coordinated Mn(Mn-N_(x)/C)single-atom electrocatalysts are considered as one of the most desirable non-precious oxygen reduction reaction(ORR)candidates due to their insignificant Fenton reactivity,high abundance,and intriguing electrocatalytic performance.However,current MnN_(x)/C single-atom electrocatalysts suffer from high overpotentials because of their low intrinsic activity and unsatisfactory chemical stability.Herein,through an in-situ polymerization-assisted pyrolysis,the Co as a second metal is introduced into the Mn-N_(x)/C system to construct Co,Mn-N_(x)dual-metallic sites,which atomically disperse in N-doped 1D carbon nanorods,denoted as Co,Mn-N/CNR and hereafter.Using electron microscopy and X-ray absorption spectroscopy(XAS)techniques,we verify the uniform dispersion of CoN4and MnN4atomic sites and confirm the effect of Co doping on the MnN_(4) electronic structure.Density functional theory(DFT)calculations further elucidate that the energy barrier of ratedetermining step(^(*)OH desorption)decreases over the 2 N-bridged MnCoN_(6) moieties related to the pure MnN_(4).This work provides an effective strategy to modulate the local coordination environment and electronic structure of MnN_(4) active sites for improving their ORR activity and stability.展开更多
Electroreduction of CO_(2) into value-added chemicals and fuels utilizing renewable electricity offers a sustainable way to meet the carbon-neutral goal and a viable solution for the storage of intermittent green ener...Electroreduction of CO_(2) into value-added chemicals and fuels utilizing renewable electricity offers a sustainable way to meet the carbon-neutral goal and a viable solution for the storage of intermittent green energy sources.At the core of this technology is the development of electrocatalysts to accelerate the redox kinetics of CO_(2) reduction reactions(CO_(2)RR)toward high targeted-product yield at minimal energy input.This perspective focuses on a unique category of CO_(2)RR electrocatalysts embodying both inorganic and organic components to synergistically promote the reaction activity,selectivity and stability.First,we summarize recent progress on the design and fabrication of organic/inorganic hybrids CO_(2)RR electrocatalysts,with special attention to the assembly protocols and structural configurations.We then carry out a comprehensive discussion on the mechanistic understanding of CO_(2)RR processes tackled jointly by the inorganic and organic phases,with respect to the regulation of mass and charge transport,modification of double-layer configuration,tailoring of intermediates adsorption,and establishment of tandem pathways.At the end,we outline future challenges in the rational design of organic/inorganic hybrids for CO_(2)RR and further extend the scope to the device level.We hope this work could incentivize more research interests to construct organic/inorganic hybrids for mobilizing electrocatalytic CO_(2)RR towards industrialization.展开更多
Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases,such as genetic diseases and cancers.Therefore,the rapid and specific monitoring of mitochondrial DNA damage is urge...Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases,such as genetic diseases and cancers.Therefore,the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition.Herein,we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN.The fluorophore was 2-styrene-1H-benzo[d]imidazole,and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA.In this design,MBI-CN conjugates to mitochondrial DNA without causing additional damages.Thus,MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage.Meanwhile,MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA.Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA,it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.展开更多
基金supported by the National Natural Science Foundation of China(No.21676300)the Shandong Provincial Natural Science Foundation(No.ZR2018MB035)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.19CX02008A and 16CX06007A)PetroChina Innovation Foundation(No.2019D-5007-0401)Taishan Scholars Program of Shandong Province(No.tsqn201909065)Tsinghua University Initiative Scientific Research Program.
文摘Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable energy conversion.In this regard,meticulous design of active sites and probing their catalytic mechanism on both cathode and anode with different reaction environment at molecular-scale are vitally necessary.Herein,a coordination environment inheriting strategy is presented for designing low-coordination Ni^(2+)octahedra(L-Ni-8)atomic interface at a high concentration(4.6 at.%).Advanced spectroscopic techniques and theoretical calculations reveal that the self-matching electron delocalization and localization state at L-Ni-8 atomic interface enable an ideal reaction environment at both cathode and anode.To improve the efficiency of using the self-modification reaction environment at L-Ni-8,all of the structural features,including high atom economy,mass transfer,and electron transfer,are integrated together from atomic-scale to macro-scale.At high current density of 500 mA/cm2,the samples synthesized at gram-scale can deliver low hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of 262 and 348 mV,respectively.
基金supported by the National Key R&D Program of China(2022YFB4102000,2022YFA1505100,2022YFA1503803)the NSFC(22002088)+1 种基金the Shanghai Sailing Program(20YF1420500)the Shanghai Science and Technology Innovation Action Plan(22dz1205500).
文摘Electrochemical CO_(2)reduction is a typical surface-mediated reaction,with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte interface and on the resultant mass transport within the hydrodynamic boundary layer in the vicinity of the cathode.To resolve the complex local reaction environment of branching CO_(2)reduction pathways,we here present a dif-ferential electrochemical mass spectroscopic(DEMS)approach for Cu electrodes to investigate CO_(2)mass trans-port,the local concentration gradients of buffering anions,and the Cu surface topology effects on CO_(2)electrolysis selectivity at a temporal resolution of~400 ms.As a proof of concept,these tuning knobs were validated on an anion exchange membrane electrolyzer,which delivered a Faradaic efficiency of up to 40.4%and a partial current density of 121 mA cm^(-2)for CO_(2)-to-C_(2)H_(4)valorization.This methodology,which bridges the study of fundamental surface electrochemistry and the upgrading of practical electrolyzer performance,could be of general interest in helping to achieve a sustainable circular carbon economy.
基金supported by the National Key Research and Development Program of China(No.2020YFB1506300)the National Natural Science Foundation of China(Nos.21922502,22075018,and 22375017)+2 种基金Young Elite Scientists Sponsorship Program by BAST(No.BYESS2023163)CNPC Innovation Found(No.2022DQ02-0606)Institute of High Energy Physics,Chinese Academy of Sciences for synchrotron radiation(BSRF)testing,Beijing Institute of Technology Research Fund Program,and Analysis and Testing Center of Beijing Institute of Technology.
文摘Precisely designing atomic metal-nitrogen-carbon(M-N-C)catalysts with asymmetric diatomic configurations and studying their structure–activity relationships for oxygen reduction reaction(ORR)are important for zinc-air batteries(ZABs).Herein,a dualatomic-site catalyst(DASC)with CoN_(3)S-MnN_(2)S_(2) configuration was prepared for the cathodes of ZABs.Compared with Co-N-C(Mn-free)and CoMn-N-C(S-free doping),CoMn-N/S-C exhibits excellent half-wave potential(0.883 V)and turnover frequency(1.54 e·s^(−1)·site^(−1)),surpassing most of the reported state-of-the-art Pt-free ORR catalysts.The CoMn-N/S-C-based ZABs achieve extremely high specific capacity(959 mAh·g^(−1))and good stability(350 h@5 mA·cm^(−2)).Density functional theory(DFT)calculation shows that the introduction of Mn and S can break the electron configuration symmetry of the original Co 3d orbital,lower the dband center of the Co site,and optimize the desorption behavior of*OH intermediate,thereby increasing the ORR activity.
基金the National Natural Science Foundation of China under Grant No.11875120the Natural Science Foundation of Zhejiang Province under Grant No.LY16A050003.
文摘Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so small(i.e.,τ→0)that it could be eliminated adiabatically.Nevertheless,whether the chimera states still exist in the opposite situation(i.e.,τ≫1)is unknown.Here,by coupling large populations of Stuart–Landau oscillators to a diffusive environment,we demonstrate that spiral wave chimeras do exist in this oscillator-environment coupling system even whenτis very large.Various transitions such as from spiral wave chimeras to spiral waves or unstable spiral wave chimeras as functions of the system parameters are explored.A physical picture for explaining the formation of spiral wave chimeras is also provided.The existence of spiral wave chimeras is further confirmed in ensembles of FitzHugh–Nagumo oscillators with the similar oscillator-environment coupling mechanism.Our results provide an affirmative answer to the observation of spiral wave chimeras in populations of oscillators mediated via a slowly changing environment and give important hints to generate chimera patterns in both laboratory and realistic chemical or biological systems.
基金the financial support from the Research Foundation for Talented Scholars of Hainan University(YEAZ22091)the financial supports from the Joint Funds of the National Natural Science Foundation of China(ZK20180055)+1 种基金the Programs for Foreign Talent(G2021106012L)the National Natural Science Foundation of China(22075290)。
文摘Carbon-based N-coordinated Mn(Mn-N_(x)/C)single-atom electrocatalysts are considered as one of the most desirable non-precious oxygen reduction reaction(ORR)candidates due to their insignificant Fenton reactivity,high abundance,and intriguing electrocatalytic performance.However,current MnN_(x)/C single-atom electrocatalysts suffer from high overpotentials because of their low intrinsic activity and unsatisfactory chemical stability.Herein,through an in-situ polymerization-assisted pyrolysis,the Co as a second metal is introduced into the Mn-N_(x)/C system to construct Co,Mn-N_(x)dual-metallic sites,which atomically disperse in N-doped 1D carbon nanorods,denoted as Co,Mn-N/CNR and hereafter.Using electron microscopy and X-ray absorption spectroscopy(XAS)techniques,we verify the uniform dispersion of CoN4and MnN4atomic sites and confirm the effect of Co doping on the MnN_(4) electronic structure.Density functional theory(DFT)calculations further elucidate that the energy barrier of ratedetermining step(^(*)OH desorption)decreases over the 2 N-bridged MnCoN_(6) moieties related to the pure MnN_(4).This work provides an effective strategy to modulate the local coordination environment and electronic structure of MnN_(4) active sites for improving their ORR activity and stability.
基金This work is supported by National Natural Science Foundation of China(No.22072101,22075193,22202020)Natural Science Foundation of Jiangsu Province(No.BK20220483,BK20211306,BK20220027)+2 种基金the Key Technology Initiative of Suzhou Municipal Science and Technology Bureau(SYG201934)Six Talent Peaks Project in Jiangsu Province(No.TD-XCL-006)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Electroreduction of CO_(2) into value-added chemicals and fuels utilizing renewable electricity offers a sustainable way to meet the carbon-neutral goal and a viable solution for the storage of intermittent green energy sources.At the core of this technology is the development of electrocatalysts to accelerate the redox kinetics of CO_(2) reduction reactions(CO_(2)RR)toward high targeted-product yield at minimal energy input.This perspective focuses on a unique category of CO_(2)RR electrocatalysts embodying both inorganic and organic components to synergistically promote the reaction activity,selectivity and stability.First,we summarize recent progress on the design and fabrication of organic/inorganic hybrids CO_(2)RR electrocatalysts,with special attention to the assembly protocols and structural configurations.We then carry out a comprehensive discussion on the mechanistic understanding of CO_(2)RR processes tackled jointly by the inorganic and organic phases,with respect to the regulation of mass and charge transport,modification of double-layer configuration,tailoring of intermediates adsorption,and establishment of tandem pathways.At the end,we outline future challenges in the rational design of organic/inorganic hybrids for CO_(2)RR and further extend the scope to the device level.We hope this work could incentivize more research interests to construct organic/inorganic hybrids for mobilizing electrocatalytic CO_(2)RR towards industrialization.
基金supported by the National Natural Science Foundation of China(Grant Nos.21722501 and 22004028)Henan Special Support for High-level Talents Central Plains Science and Technology Innovation Leading Talents(Grant No.204200510006)Key Project of Science and Technology of Henan Province(Grant No.202102310139)。
文摘Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases,such as genetic diseases and cancers.Therefore,the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition.Herein,we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN.The fluorophore was 2-styrene-1H-benzo[d]imidazole,and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA.In this design,MBI-CN conjugates to mitochondrial DNA without causing additional damages.Thus,MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage.Meanwhile,MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA.Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA,it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.
