This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and gr...This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and graphs which supersede those given in Ame2016.The first table presents the recommended atomic mass values and their uncertainties.It is followed by a table of the influences of data on primary nuclides,a table of various reaction and decay energies,and finally,a series of graphs of separation and decay energies.The last section of this paper provides all input data references that were used in the Ame2020 and the Nubase2020 evaluations.展开更多
An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in...An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in alkaline conditions.Herein,we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks(Fe-Zn-SA/NC),which works efficiently as ORR catalyst in the whole pH range.It achieves high half-wave potentials of 0.78,0.85 and 0.72 V in 0.1 M HClO4,0.1 M KOH and 0.1 M phosphate buffer saline(PBS)solutions,respectively,as well as respectable stability.The performances are even comparable to Pt/C.Furthermore,when assembled into a Zn-air battery,the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices.Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers.This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.展开更多
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
The demand for high-performance non-precious-metal electrocatalysts to replace the noble metal-based catalysts for oxygen reduction reaction(ORR)is intensively increasing.Herein,single-atomic copper sites supported on...The demand for high-performance non-precious-metal electrocatalysts to replace the noble metal-based catalysts for oxygen reduction reaction(ORR)is intensively increasing.Herein,single-atomic copper sites supported on N-doped three-dimensional hierarchically porous carbon catalyst(Cu_(1)/NC)was prepared by coordination pyrolysis strategy.Remarkably,the Cu_(1)/NC-900 catalyst not only exhibits excellent ORR performance with a half-wave potential of 0.894 V(vs.RHE)in alkaline media,outperforming those of commercial Pt/C(0.851 V)and Cu nanoparticles anchored on N-doped porous carbon(CuNPs/NC-900),but also demonstrates high stability and methanol tolerance.Moreover,the Cu_(1)/NC-900 based Zn-air battery exhibits higher power density,rechargeability and cyclic stability than the one based on Pt/C.Both experimental and theoretical investigations demonstrated that the excellent performance of the as-obtained Cu_(1)/NC-900 could be attributed to the synergistic effect between copper coordinated by three N atoms active sites and the neighbouring carbon defect,resulting in elevated Cu d-band centers of Cu atoms and facilitating intermediate desorption for ORR process.This study may lead towards the development of highly efficient non-noble metal catalysts for applications in electrochemical energy conversion.展开更多
A highly active interface can enhance the catalytic efficiency of catalysts toward the oxygen evolution reaction(OER).However,accurately tuning their atomic interface configurations of defects with sufficient activity...A highly active interface can enhance the catalytic efficiency of catalysts toward the oxygen evolution reaction(OER).However,accurately tuning their atomic interface configurations of defects with sufficient activity and stability remains a grand challenge.Herein,we report on breaking the activity and stability limits of CoO_(x) nanosheets in the OER process by constructing copious high-energy atomic steps and cavities,in which S or Ce atoms simultaneously replace O or Co atoms from CoO_(x),thus achieving high-energy atomic interface Ce,O-Co_(3)S_(4) nanosheets.By combining in situ characterization and density functional theory calculations,it is shown that the unique orbital coupling between Ce-4f,O(S)-2p,and Co-3d causes it to be closer to the Fermi level,leading to faster charge transfer capability.More importantly,the novel structure breaks the stability limit of cobalt sulfide with planar defects,which gives high catalytic activity and stability in 0.1 M KOH solutions,better than commercial RuO_(2) and IrO_(2) noble metal catalysts.As expected,Ce,O-Co_(3)S_(4) possesses much better turnover frequency activity(0.064 s^(-1))at an overpotential of 300 mV,which is ~7 times larger than that of Ce-CoO_(x)(0.009 s^(-1)).Our work presents a new perspective of designing catalysts with atomically dispersed orbital electronic coupling defects toward efficient OER electrocatalysis.展开更多
Controllable design and synthesis of catalysts with the target active sites are extremely important for their applications such as for the oxygen reduction reaction(ORR)in fuel cells.However,the controllably synthesiz...Controllable design and synthesis of catalysts with the target active sites are extremely important for their applications such as for the oxygen reduction reaction(ORR)in fuel cells.However,the controllably synthesizing electrocatalysts with a single type of active site still remains a grand challenge.In this study,we developed a facile and scalable method for fabricating highly efficient ORR electrocatalysts with sole atomic Fe-N4 species as the active site.Herein,the use of cost-effective highly porous carbon as the support not only could avoid the aggregation of the atomic Fe species but also a feasible approach to reduce the catalyst cost.The obtained atomic Fe-N4 in activated carbon(aFe@AC)shows excellent ORR activity.Its half-wave potential is 59 mV more negative but 47 mV more positive than that of the commercial Pt/C in acidic and alkaline electrolytes,respectively.The full cell performance test results show that the aFe@AC sample is a promising candidate for direct methanol fuel cells.This study provides a general method to prepare catalysts with a certain type of active site and definite numbers.展开更多
Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very...Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very important to reasonably control the atomic structure and determine the structure-activity relationship between the atomic configurations and the hydrogen evolution reaction(HER)performance.Although numerous studies have indicated that doping can yield diverse atomic structure configurations,there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance.Here,diverse atomic structure configurations of adsorptive doping,substitutional doping,and TMDs alloys are summarized.The structure-activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory(DFT)calculations.These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER.Finally,we have summarized the current challenges and future opportunities,offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts.展开更多
The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated o...The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated on porous Ni（OH）2 nanowires （NWs） via a facile room-temperature synthesis strategy. The as-obtained Ptc/Ni（OH）2 catalyst exhibits highly efficient hydrogen evolution reaction （HER） performance under basic conditions. In 0.1moll-1 KOH, the Ptc/Ni（OH）2 has an onset overpotential of -0 mV vs. RHE, and a significantly low overpotential of 32 mV at a current density of 10mAcm-2, lower than that of the com- mercial 20% Pt/C （58 mV）. The mass current density data illustrated that the PL/Ni（OH）2 reached a high current den- sity of 6.34Amg^-1i at an overpotential of 50 mV, which was approximately 28 times higher than that of the commercial Pt/C （0.223Amg^-1i） at the same overpotential, proving the high-efficiency electrocatalytic activity of the as-obtained Ptc/Ni（OH）2 for HER under alkaline conditions.展开更多
Iron-nitrogen-carbon single-atom catalysts(Fe-N-C SACs)are widely acknowledged for their effective oxygen reduction activity,however,their activity requires further enhancement.Meanwhile,additional structural optimiza...Iron-nitrogen-carbon single-atom catalysts(Fe-N-C SACs)are widely acknowledged for their effective oxygen reduction activity,however,their activity requires further enhancement.Meanwhile,additional structural optimization is necessary to enhance mass transport and achieve higher power density in practical applications.Herein,using ZIF-8 as a template,we synthesized yolk-shell catalysts featuring complex sites of Fe single atoms and Cu nanoclusters(y-FeCu/NC)via partial etching and liquid-phase loading.The synthesized y-FeCu/NC catalyst exhibits high specific surface area and mesoporous volume.Combined with the advantages of highly active sites and yolk-shell structure,the y-FeCu/NC catalyst demonstrated outstanding catalytic performance in the oxygen reduction reaction,achieving a half-wave potential(E_(1/2))of 0.97 V in 0.1 M KOH.As a practical energy device,Zn-air battery(ZAB)assembled with y-FeCu/NC catalyst achieved a remarkable power density of 356.3 mW·cm^(-2),representing an improvement of approximately 28.5%compared to its solid FeCu/NC counterpart.Furthermore,it showcased impressive stability,surpassing all control samples.展开更多
Ammonia(NH_(3))is an important raw material for modern agriculture and industry,being widely demanded to sustain the sustainable development of modern society.Currently,the industrial production methods of NH_(3),such...Ammonia(NH_(3))is an important raw material for modern agriculture and industry,being widely demanded to sustain the sustainable development of modern society.Currently,the industrial production methods of NH_(3),such as the traditional Haber-Bosch process,have drawbacks including high energy consumption and significant carbon dioxide emissions.In recent years,the electrocatalytic nitrate reduction reaction(NO_(3)RR)powered by intermittent renewable energy sources has gradually become a multidisciplinary research hotspot,as it allows for the efficient synthesis of NH_(3)under mild conditions.In this review,we focus on the research of electrocatalysts with atomic-level site,which have attracted attention due to their extremely high atomic utilization efficiency and unique structural characteristics in the field of NO_(3)RR.Firstly,we introduce the mechanism of nitrate reduction for ammonia synthesis and discuss the in-situ characterization techniques related to the mechanism study.Secondly,we review the progress of the electrocatalysts with atomic-level site for nitrate reduction and explore the structure-activity relationship to guide the rational design of efficient catalysts.Lastly,the conclusions of this review and the challenges and prospective of this promising field are presented.展开更多
Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to d...Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to deposit highly uniform conformal pinhole-free thin films with angstrom-level thickness control,particularly on 3D topologies.Over the years,the ALD technology has enabled not only the successful downscaling of the microelectronic devices but also numerous novel 3D device structures.As ALD is essentially a variant of chemical vapor deposition,a comprehensive understanding of the involved chemistry is of crucial importance to further develop and utilize this technology.To this end,we,in this review,focus on the surface chemistry and precursor chemistry aspects of ALD.We first review the surface chemistry of the gas–solid ALD reactions and elaborately discuss the associated mechanisms for the film growth;then,we review the ALD precursor chemistry by comparatively discussing the precursors that have been commonly used in the ALD processes;and finally,we selectively present a few newly-emerged applications of ALD in microelectronics,followed by our perspective on the future of the ALD technology.展开更多
The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggis...The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggish oxygen reduction reaction(ORR)at the cathode.Herein,we report a facile and scalable strategy for the large-scale preparation of a free-standing and flexible porous atomically dispersed Fe-N-doped carbon microtube(FeSAC/PCMT)sponge.Benefiting from its unique structure that greatly facilitates the catalytic kinetics,mass transport,and electron transfer,our FeSAC/PCMT electrode exhibits excellent performance with an ORR potential of 0.942 V at^(-3) mA cm^(-2).When the FeSAC/PCMT sponge was directly used as an oxygen electrode for liquid-state and flexible solid-state zinc-air batteries,high peak power densities of 183.1 and 58.0 mW cm^(-2) were respectively achieved,better than its powdery counterpart and commercial Pt/C catalyst.Experimental and theoretical investigation results demonstrate that such ultrahigh ORR performance can be attributed to atomically dispersed Fe-N_(5) species in FeSAC/PCMT.This study presents a cost-effective and scalable strategy for the fabrication of highly efficient and flexible oxygen electrodes,provides a significant new insight into the catalytic mechanisms,and helps to realize significant advances in energy devices.展开更多
Mass production of highly efficient,durable,and inexpensive single atomic catalysts is currently the major challenge associated with the oxygen reduction reaction(ORR)for fuel cells.In this study,we develop a general ...Mass production of highly efficient,durable,and inexpensive single atomic catalysts is currently the major challenge associated with the oxygen reduction reaction(ORR)for fuel cells.In this study,we develop a general strategy that uses a simple ultrasonic atomization coupling with pyrolysis and calcination process to synthesize single atomic FeNC catalysts(FeNC SACs)at large scale.The microstructure characterizations confirm that the active centers root in the single atomic Fe sites chelating to the four-fold pyridinic N atoms.The identified specific Fe active sites with the variable valence states facilitate the transfer of electrons,endowing the FeNC SACs with excellent electrochemical ORR activity.The FeNC SACs were used as cathode catalysts in a homemade Zn-air battery,giving an open-circuit voltage(OCV)of 1.43 V,which is substantially higher than that of commercial Pt/C catalysts.This study provides a simple approach to the synthesis of single atomic catalysts at large scale.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is considered an efficient way to convert CO_(2)into high-value-added chemicals,and thus is of significant social and economic value.Metal single-atomic site catalyst...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is considered an efficient way to convert CO_(2)into high-value-added chemicals,and thus is of significant social and economic value.Metal single-atomic site catalysts(SASCs)generally have excellent selectivity because of their 100%atomic utilization and uniform structure of active sites,and thus promise a broad range of applications.However,SASCs still face challenges such as low intrinsic activity and low density of active sites.Precise regulation of the microstructures of SASCs is an effective method to improve their CO_(2)RR performance and to obtain deep reduction products.In this article,we systematically summarize the current research status of SASCs developed for highly efficient catalysis of CO_(2)RR,discuss the various structural regulation methods for enhanced activity and selectivity of SASCs for CO_(2)RR,and review the application of in-situ characterization technologies in the SASC-catalyzed CO_(2)RR.We then discuss the problems yet to be solved in this area,and propose the future directions of the research on the design and application of SASCs for CO_(2)RR.展开更多
Fine regulation of geometric structures has great promise to acquire specific electronic structures and improve the catalytic performance of single-atom catalysts,yet it remains a challenge.Herein,a novel seed encapsu...Fine regulation of geometric structures has great promise to acquire specific electronic structures and improve the catalytic performance of single-atom catalysts,yet it remains a challenge.Herein,a novel seed encapsulation–decomposition strategy is proposed for the geometric distortion engineering and thermal atomization of a series of Cu-N_(x)/S moieties anchored on carbon supports.During pyrolysis,seeds(Cu^(2+),CuO,or Cu_(7)S_(4) nanoparticles)confined in metal organic framework can accommodate single Cu atoms with Cu–N or Cu–S coordination bonds and simultaneously induce C–S or C–N bond cleavage in the second coordination shell of Cu centers,which are identified to manipulate the distortion degree of Cu-N_(x)/S moieties.The severely distorted Cu-N3S molecular structure endows the resultant catalyst with excellent oxygen reduction reaction activity(E_(1/2)=0.885 V)and zinc-air battery performance(peak power density of 210 mW·cm^(−2)),outperforming the asymmetrical and symmetrical Cu-N4 structures.A combined experimental and theoretical study reveals that the geometric distortion of Cu-N_(x)/S moieties creates uneven charge distribution by a unique topological correlation effect,which increases the metal charge and shifts the d-band center toward the Fermi level,thereby optimizing the inter-mediate adsorption energy.展开更多
Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,fro...Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,from the atomic-scale engineering we develop a high intrinsic activity ORR catalyst in terms of incorporating atomically dispersed dual Fe centers(single Fe atoms and ultra-small Fe atomic clusters)into bamboo-like N-doped carbon nanotubes.Benefiting from atomically dispersed dual-Fe centers on the atomic interface of Fe-Nx/carbon nanotubes,the fabricated dual Fe centers catalyst exhibits an extremely high ORR activity(E_(onset)=1.006 V;E_(1/2)=0.90 V),beyond state-of-the-art Pt/C.Remarkably,this catalyst also shows a superior kinetic current density of 19.690 mA·cm^(−2),which is 7 times that of state-of-the-art Pt/C.Additionally,based on the excellent catalyst,the primary Zn-air battery reveals a high power density up to 137 mW·cm^(−2) and sufficient potential cycling stability(at least 25 h).Undoubtedly,given the unique structure–activity relationship of dual-Fe active species and metal-nitrogen-carbon substrates,the catalyst will show great prospects in highly efficient electrochemical energy conversion devices.展开更多
A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making curren...A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making current-based Si devices.Thus,the microstructure control of silicide formation on the basis of kinetics of nucleation and growth has relevant applications in microelectronic technology.Repeating events of homogeneous nucleation of epitaxial silicides of Ni and Co on Si in atomic layer reaction is presented.The chemical effort on intrinsic diffusivities in diffusion-controlled layer-typed intermetallic compound growth of Ni2Si is analyzed.展开更多
For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based cataly...For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based catalysts, such as Pt-based catalysts, atomically dispersed metal–nitrogen–carbon(M–N–C) catalysts are popularity and show great potential in maximizing active site density, high atom utilization and high activity,making them the first choice to replace Pt-based catalysts. In the preparation of atomically dispersed metal–nitrogen–carbon catalyst, it is difficult to ensure that all active sites are uniformly dispersed, and the structure system of the active sites is not optimal. Based on this, we focus on various approaches for preparing M–N–C catalysts that are conducive to atomic dispersion, and the influence of the chemical environmental regulation of atoms on the catalytic sites in different catalysts. Therefore, we discuss the chemical environmental regulation of the catalytic sites by bimetals, atom clusters, and heteroatoms(B, S, and P). The active sites of M–N–C catalysts are explored in depth from the synthesis and characterization, reaction mechanisms, and density functional theory(DFT)calculations. Finally, the existing problems and development prospects of the current atomic dispersion M–N–C catalyst are proposed in detail.展开更多
基金This work is supported in part by the Strategic Priority Research Program of Chinese Academy of Sciences(CAS,Grant No.XDB34000000)the National Key Research and Development Program of China(Grant No.2016YFA0400504)the U.S.Department of Energy,Of-fice of Science,Office of Nuclear Physics,under Contract No.DE-AC02-06CH11357.
文摘This is the second part of the new evaluation of atomic masses,Ame2020.Using least-squares adjustments to all evaluated and accepted experimental data,described in Part I,we derived tables with numerical values and graphs which supersede those given in Ame2016.The first table presents the recommended atomic mass values and their uncertainties.It is followed by a table of the influences of data on primary nuclides,a table of various reaction and decay energies,and finally,a series of graphs of separation and decay energies.The last section of this paper provides all input data references that were used in the Ame2020 and the Nubase2020 evaluations.
基金This work was financially supported by National Key R&D Program of China(No.2017YFA0700104)the National Natural Science Foundation of China(Nos.22075211,21601136,51971157,51761165012,and 62005173)+2 种基金Project funded by China Postdoctoral Science Foundation(No.2020TQ0201)Tianjin Science Fund for Distinguished Young Scholars(No.19JCJQJC61800)The authors also acknowledge National Supercomputing Center in Shenzhen for providing the computational resources and materials studio(version 7.0,DMol3).
文摘An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in alkaline conditions.Herein,we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks(Fe-Zn-SA/NC),which works efficiently as ORR catalyst in the whole pH range.It achieves high half-wave potentials of 0.78,0.85 and 0.72 V in 0.1 M HClO4,0.1 M KOH and 0.1 M phosphate buffer saline(PBS)solutions,respectively,as well as respectable stability.The performances are even comparable to Pt/C.Furthermore,when assembled into a Zn-air battery,the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices.Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers.This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.
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the National Natural Science Foundation of China(Nos.21804319,21971002)the Natural Science Foundation of Anhui province(Nos.1908085QB45 and 2008085QB81)the Education Departm ent of Anhui Province Foundation(No.KJ2019A0503).We thank the BL14W1 station in Shanghai Synchrotron Radiation Facility(SSRF)and 1W1B station for XAFS measurement in Beijing Synchrotron Radiation Facility(BSRF).The calculations in this paper have been done on the supercomputing system of the National Supercomputing Center in Changsha.
文摘The demand for high-performance non-precious-metal electrocatalysts to replace the noble metal-based catalysts for oxygen reduction reaction(ORR)is intensively increasing.Herein,single-atomic copper sites supported on N-doped three-dimensional hierarchically porous carbon catalyst(Cu_(1)/NC)was prepared by coordination pyrolysis strategy.Remarkably,the Cu_(1)/NC-900 catalyst not only exhibits excellent ORR performance with a half-wave potential of 0.894 V(vs.RHE)in alkaline media,outperforming those of commercial Pt/C(0.851 V)and Cu nanoparticles anchored on N-doped porous carbon(CuNPs/NC-900),but also demonstrates high stability and methanol tolerance.Moreover,the Cu_(1)/NC-900 based Zn-air battery exhibits higher power density,rechargeability and cyclic stability than the one based on Pt/C.Both experimental and theoretical investigations demonstrated that the excellent performance of the as-obtained Cu_(1)/NC-900 could be attributed to the synergistic effect between copper coordinated by three N atoms active sites and the neighbouring carbon defect,resulting in elevated Cu d-band centers of Cu atoms and facilitating intermediate desorption for ORR process.This study may lead towards the development of highly efficient non-noble metal catalysts for applications in electrochemical energy conversion.
基金supported by the National Natural Science Foundation of China(NSFC)(grant no.22075223)the Natural Science Foundation of Jiangsu(grant no.BK20201120)+2 种基金the Innovation Project of Jiangsu Province,Excellent Scientific and Technological Innovation Team of Colleges and Universities of Jiangsu Province(grant no.SUJIAOKE 2021 No.1)the Key Subject of Ecology of Jiangsu Province(grant no.SUJIAOYANHAN 2022 No.2)Scientific and Technological Innovation Team of Nanjing(grant no.NINGJIAOGAOSHI 2021 No.16).
文摘A highly active interface can enhance the catalytic efficiency of catalysts toward the oxygen evolution reaction(OER).However,accurately tuning their atomic interface configurations of defects with sufficient activity and stability remains a grand challenge.Herein,we report on breaking the activity and stability limits of CoO_(x) nanosheets in the OER process by constructing copious high-energy atomic steps and cavities,in which S or Ce atoms simultaneously replace O or Co atoms from CoO_(x),thus achieving high-energy atomic interface Ce,O-Co_(3)S_(4) nanosheets.By combining in situ characterization and density functional theory calculations,it is shown that the unique orbital coupling between Ce-4f,O(S)-2p,and Co-3d causes it to be closer to the Fermi level,leading to faster charge transfer capability.More importantly,the novel structure breaks the stability limit of cobalt sulfide with planar defects,which gives high catalytic activity and stability in 0.1 M KOH solutions,better than commercial RuO_(2) and IrO_(2) noble metal catalysts.As expected,Ce,O-Co_(3)S_(4) possesses much better turnover frequency activity(0.064 s^(-1))at an overpotential of 300 mV,which is ~7 times larger than that of Ce-CoO_(x)(0.009 s^(-1)).Our work presents a new perspective of designing catalysts with atomically dispersed orbital electronic coupling defects toward efficient OER electrocatalysis.
基金The authors would like to thank the Australian Research Council(ARC DP170103317,DP200103043)for financial support during the course of this study.Prof Jun Chen would like to thank the Australian National Fabrication Facility and EMC at the University of Wollongong for facilities/equipment access.
文摘Controllable design and synthesis of catalysts with the target active sites are extremely important for their applications such as for the oxygen reduction reaction(ORR)in fuel cells.However,the controllably synthesizing electrocatalysts with a single type of active site still remains a grand challenge.In this study,we developed a facile and scalable method for fabricating highly efficient ORR electrocatalysts with sole atomic Fe-N4 species as the active site.Herein,the use of cost-effective highly porous carbon as the support not only could avoid the aggregation of the atomic Fe species but also a feasible approach to reduce the catalyst cost.The obtained atomic Fe-N4 in activated carbon(aFe@AC)shows excellent ORR activity.Its half-wave potential is 59 mV more negative but 47 mV more positive than that of the commercial Pt/C in acidic and alkaline electrolytes,respectively.The full cell performance test results show that the aFe@AC sample is a promising candidate for direct methanol fuel cells.This study provides a general method to prepare catalysts with a certain type of active site and definite numbers.
基金supported by the Natural Science Foundation of China(No.51902101)the Natural Science Foundation of Jiangsu Province(No.BK20201381)+1 种基金the Science Foundation of Nanjing University of Posts and Telecommunications(Nos.NY219144,NY221046)the National College Student Innovation and Entrepreneurship Training Program(No.202210293171K).
文摘Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very important to reasonably control the atomic structure and determine the structure-activity relationship between the atomic configurations and the hydrogen evolution reaction(HER)performance.Although numerous studies have indicated that doping can yield diverse atomic structure configurations,there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance.Here,diverse atomic structure configurations of adsorptive doping,substitutional doping,and TMDs alloys are summarized.The structure-activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory(DFT)calculations.These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER.Finally,we have summarized the current challenges and future opportunities,offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts.
基金financial support from the National Natural Science Foundation of China(21425103,21673280 and 11374039)
文摘The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated on porous Ni（OH）2 nanowires （NWs） via a facile room-temperature synthesis strategy. The as-obtained Ptc/Ni（OH）2 catalyst exhibits highly efficient hydrogen evolution reaction （HER） performance under basic conditions. In 0.1moll-1 KOH, the Ptc/Ni（OH）2 has an onset overpotential of -0 mV vs. RHE, and a significantly low overpotential of 32 mV at a current density of 10mAcm-2, lower than that of the com- mercial 20% Pt/C （58 mV）. The mass current density data illustrated that the PL/Ni（OH）2 reached a high current den- sity of 6.34Amg^-1i at an overpotential of 50 mV, which was approximately 28 times higher than that of the commercial Pt/C （0.223Amg^-1i） at the same overpotential, proving the high-efficiency electrocatalytic activity of the as-obtained Ptc/Ni（OH）2 for HER under alkaline conditions.
基金supported by the National Key Research and Development Program of China(No.2022YFC2105900).
文摘Iron-nitrogen-carbon single-atom catalysts(Fe-N-C SACs)are widely acknowledged for their effective oxygen reduction activity,however,their activity requires further enhancement.Meanwhile,additional structural optimization is necessary to enhance mass transport and achieve higher power density in practical applications.Herein,using ZIF-8 as a template,we synthesized yolk-shell catalysts featuring complex sites of Fe single atoms and Cu nanoclusters(y-FeCu/NC)via partial etching and liquid-phase loading.The synthesized y-FeCu/NC catalyst exhibits high specific surface area and mesoporous volume.Combined with the advantages of highly active sites and yolk-shell structure,the y-FeCu/NC catalyst demonstrated outstanding catalytic performance in the oxygen reduction reaction,achieving a half-wave potential(E_(1/2))of 0.97 V in 0.1 M KOH.As a practical energy device,Zn-air battery(ZAB)assembled with y-FeCu/NC catalyst achieved a remarkable power density of 356.3 mW·cm^(-2),representing an improvement of approximately 28.5%compared to its solid FeCu/NC counterpart.Furthermore,it showcased impressive stability,surpassing all control samples.
基金financial support from the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX24_0690)financial support from the National Natural Science Foundation of China (Project No. 22275088, 52101260)+4 种基金the Project of Shuangchuang Scholar of Jiangsu Province (Project No. JSSCBS20210212)the Fundamental Research Funds for the Central Universities (Project No. 30921011203)the Start-Up Grant (Project No. AE89991/340) from Nanjing University of Science and Technologyfinancial support from the Foundation of Jiangsu Educational Committee (22KJB310008)the Senior Talent Program of Jiangsu University (20JDG073)
文摘Ammonia(NH_(3))is an important raw material for modern agriculture and industry,being widely demanded to sustain the sustainable development of modern society.Currently,the industrial production methods of NH_(3),such as the traditional Haber-Bosch process,have drawbacks including high energy consumption and significant carbon dioxide emissions.In recent years,the electrocatalytic nitrate reduction reaction(NO_(3)RR)powered by intermittent renewable energy sources has gradually become a multidisciplinary research hotspot,as it allows for the efficient synthesis of NH_(3)under mild conditions.In this review,we focus on the research of electrocatalysts with atomic-level site,which have attracted attention due to their extremely high atomic utilization efficiency and unique structural characteristics in the field of NO_(3)RR.Firstly,we introduce the mechanism of nitrate reduction for ammonia synthesis and discuss the in-situ characterization techniques related to the mechanism study.Secondly,we review the progress of the electrocatalysts with atomic-level site for nitrate reduction and explore the structure-activity relationship to guide the rational design of efficient catalysts.Lastly,the conclusions of this review and the challenges and prospective of this promising field are presented.
基金supported by NSFC(22175005)Guangdong Basic and Applied Basic Research Foundation(2020B1515120039)+1 种基金Shenzhen Fundamental Research Program(JCYJ20200109110628172,GXWD20201231165807007-20200802205241003)Guangdong Technology Center for Oxide Semiconductor Devices and ICs。
文摘Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to deposit highly uniform conformal pinhole-free thin films with angstrom-level thickness control,particularly on 3D topologies.Over the years,the ALD technology has enabled not only the successful downscaling of the microelectronic devices but also numerous novel 3D device structures.As ALD is essentially a variant of chemical vapor deposition,a comprehensive understanding of the involved chemistry is of crucial importance to further develop and utilize this technology.To this end,we,in this review,focus on the surface chemistry and precursor chemistry aspects of ALD.We first review the surface chemistry of the gas–solid ALD reactions and elaborately discuss the associated mechanisms for the film growth;then,we review the ALD precursor chemistry by comparatively discussing the precursors that have been commonly used in the ALD processes;and finally,we selectively present a few newly-emerged applications of ALD in microelectronics,followed by our perspective on the future of the ALD technology.
基金supported by the start-up fund from Kunming University of Science and Technology,the National Natural Science Foundation of China (Grants 52102046,51872293,52130209,52072375)Liaoning Revitalization Talents Program (XLYC2002037)Basic Research Project of Natural Science Foundation of Shandong Province,China (ZR2019ZD49).
文摘The keen interest in fuel cells and metal-air batteries stimulates a great deal of research on the development of a cost-efficient and high-performance catalyst as an alternative to traditional Pt to boost the sluggish oxygen reduction reaction(ORR)at the cathode.Herein,we report a facile and scalable strategy for the large-scale preparation of a free-standing and flexible porous atomically dispersed Fe-N-doped carbon microtube(FeSAC/PCMT)sponge.Benefiting from its unique structure that greatly facilitates the catalytic kinetics,mass transport,and electron transfer,our FeSAC/PCMT electrode exhibits excellent performance with an ORR potential of 0.942 V at^(-3) mA cm^(-2).When the FeSAC/PCMT sponge was directly used as an oxygen electrode for liquid-state and flexible solid-state zinc-air batteries,high peak power densities of 183.1 and 58.0 mW cm^(-2) were respectively achieved,better than its powdery counterpart and commercial Pt/C catalyst.Experimental and theoretical investigation results demonstrate that such ultrahigh ORR performance can be attributed to atomically dispersed Fe-N_(5) species in FeSAC/PCMT.This study presents a cost-effective and scalable strategy for the fabrication of highly efficient and flexible oxygen electrodes,provides a significant new insight into the catalytic mechanisms,and helps to realize significant advances in energy devices.
基金the National Natural Science Foundation of China(NSFC,51971029)the NSFC-BRICS STI Framework Program(51861145309)+4 种基金the National S&T Major Project(2018ZX10301201)the Joint Research Project of University of Science and Technology Beijing&Taipei University of Technology(TW2018007)the“1125”Zhihui Zhengzhou Talent Project of Henan Province(39080070)the Fundamental Research Funds for the Central Universities(FRF-BR-15-027A)the fund supports from the“100 talent plan”fund of Fujian province(Contract No:2017-802)。
文摘Mass production of highly efficient,durable,and inexpensive single atomic catalysts is currently the major challenge associated with the oxygen reduction reaction(ORR)for fuel cells.In this study,we develop a general strategy that uses a simple ultrasonic atomization coupling with pyrolysis and calcination process to synthesize single atomic FeNC catalysts(FeNC SACs)at large scale.The microstructure characterizations confirm that the active centers root in the single atomic Fe sites chelating to the four-fold pyridinic N atoms.The identified specific Fe active sites with the variable valence states facilitate the transfer of electrons,endowing the FeNC SACs with excellent electrochemical ORR activity.The FeNC SACs were used as cathode catalysts in a homemade Zn-air battery,giving an open-circuit voltage(OCV)of 1.43 V,which is substantially higher than that of commercial Pt/C catalysts.This study provides a simple approach to the synthesis of single atomic catalysts at large scale.
基金supported by Taishan Scholars Program of Shandong Province(No.tsqn201909065)Shandong Provincial Natural Science Foundation(Nos.ZR2021YQ15 and ZR2020QB174)+1 种基金the National Natural Science Foundation of China(No.22108306)Postgraduate Innovation Fund of China University of Petroleum(East China)(No.YCX2021064)。
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is considered an efficient way to convert CO_(2)into high-value-added chemicals,and thus is of significant social and economic value.Metal single-atomic site catalysts(SASCs)generally have excellent selectivity because of their 100%atomic utilization and uniform structure of active sites,and thus promise a broad range of applications.However,SASCs still face challenges such as low intrinsic activity and low density of active sites.Precise regulation of the microstructures of SASCs is an effective method to improve their CO_(2)RR performance and to obtain deep reduction products.In this article,we systematically summarize the current research status of SASCs developed for highly efficient catalysis of CO_(2)RR,discuss the various structural regulation methods for enhanced activity and selectivity of SASCs for CO_(2)RR,and review the application of in-situ characterization technologies in the SASC-catalyzed CO_(2)RR.We then discuss the problems yet to be solved in this area,and propose the future directions of the research on the design and application of SASCs for CO_(2)RR.
基金supported by the National Natural Science Foundation of China(Nos.21701005 and 21903001)the Fundamental Research Funds for the Central Universities(No.XK2020-02)China Petroleum&Chemical Corporation(SINOPEC)(No.421028)。
文摘Fine regulation of geometric structures has great promise to acquire specific electronic structures and improve the catalytic performance of single-atom catalysts,yet it remains a challenge.Herein,a novel seed encapsulation–decomposition strategy is proposed for the geometric distortion engineering and thermal atomization of a series of Cu-N_(x)/S moieties anchored on carbon supports.During pyrolysis,seeds(Cu^(2+),CuO,or Cu_(7)S_(4) nanoparticles)confined in metal organic framework can accommodate single Cu atoms with Cu–N or Cu–S coordination bonds and simultaneously induce C–S or C–N bond cleavage in the second coordination shell of Cu centers,which are identified to manipulate the distortion degree of Cu-N_(x)/S moieties.The severely distorted Cu-N3S molecular structure endows the resultant catalyst with excellent oxygen reduction reaction activity(E_(1/2)=0.885 V)and zinc-air battery performance(peak power density of 210 mW·cm^(−2)),outperforming the asymmetrical and symmetrical Cu-N4 structures.A combined experimental and theoretical study reveals that the geometric distortion of Cu-N_(x)/S moieties creates uneven charge distribution by a unique topological correlation effect,which increases the metal charge and shifts the d-band center toward the Fermi level,thereby optimizing the inter-mediate adsorption energy.
基金the National Natural Science Foundation of China(NSFC)(Nos.21501096 and 22075223)Natural Science Foundation of Jiangsu(Nos.BK20150086 and BK20201120)+2 种基金Foundation of the Jiangsu Education Committee(No.15KJB150020)the Six Talent Peaks Project in Jiangsu Province(No.JY-087)Innovation Project of Jiangsu Province.
文摘Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,from the atomic-scale engineering we develop a high intrinsic activity ORR catalyst in terms of incorporating atomically dispersed dual Fe centers(single Fe atoms and ultra-small Fe atomic clusters)into bamboo-like N-doped carbon nanotubes.Benefiting from atomically dispersed dual-Fe centers on the atomic interface of Fe-Nx/carbon nanotubes,the fabricated dual Fe centers catalyst exhibits an extremely high ORR activity(E_(onset)=1.006 V;E_(1/2)=0.90 V),beyond state-of-the-art Pt/C.Remarkably,this catalyst also shows a superior kinetic current density of 19.690 mA·cm^(−2),which is 7 times that of state-of-the-art Pt/C.Additionally,based on the excellent catalyst,the primary Zn-air battery reveals a high power density up to 137 mW·cm^(−2) and sufficient potential cycling stability(at least 25 h).Undoubtedly,given the unique structure–activity relationship of dual-Fe active species and metal-nitrogen-carbon substrates,the catalyst will show great prospects in highly efficient electrochemical energy conversion devices.
文摘A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making current-based Si devices.Thus,the microstructure control of silicide formation on the basis of kinetics of nucleation and growth has relevant applications in microelectronic technology.Repeating events of homogeneous nucleation of epitaxial silicides of Ni and Co on Si in atomic layer reaction is presented.The chemical effort on intrinsic diffusivities in diffusion-controlled layer-typed intermetallic compound growth of Ni2Si is analyzed.
基金financial support from the National Natural Science Foundation of China (Nos. 21875221, 21571157, U1604123, and 21773016)the Youth Talent Support Program of HighLevel Talents Special Support Plan in Henan Province (ZYQR201810148)+1 种基金Creative talents in the Education Department of Henan Province (19HASTIT039)the project supported by State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology) (2019-KF-13)
文摘For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based catalysts, such as Pt-based catalysts, atomically dispersed metal–nitrogen–carbon(M–N–C) catalysts are popularity and show great potential in maximizing active site density, high atom utilization and high activity,making them the first choice to replace Pt-based catalysts. In the preparation of atomically dispersed metal–nitrogen–carbon catalyst, it is difficult to ensure that all active sites are uniformly dispersed, and the structure system of the active sites is not optimal. Based on this, we focus on various approaches for preparing M–N–C catalysts that are conducive to atomic dispersion, and the influence of the chemical environmental regulation of atoms on the catalytic sites in different catalysts. Therefore, we discuss the chemical environmental regulation of the catalytic sites by bimetals, atom clusters, and heteroatoms(B, S, and P). The active sites of M–N–C catalysts are explored in depth from the synthesis and characterization, reaction mechanisms, and density functional theory(DFT)calculations. Finally, the existing problems and development prospects of the current atomic dispersion M–N–C catalyst are proposed in detail.
