The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge d...The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge distribution of the traditional M-N_(4)active site,the adsorption energy of the key oxygen intermediates in the process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is difficult to reach the optimal value,which seriously limits the catalytic efficiency.The core of solving this problem lies in the accurate modulation of the coordination environment of the M-N_(4)site,which can realize the breakthrough improvement of the catalytic performance by synergistically optimizing the geometric configuration and electronic structure.In this paper,we systematically analyze the ORR/OER reaction mechanism and then comprehensively review the four main strategies to optimize the coordination environment of M-N-C:metal site regulation,coordination number engineering,non-metal atom doping,and carbon support regulation.Through an in-depth analysis of the structure-activity relationship between the coordination configuration and catalytic performance,the core challenges faced by current research are pointed out,and future research directions are envisioned.This work aims to provide theoretical references for the directional construction of highly efficient M-N-C catalysts with optimized coordination environments.展开更多
Aqueous zinc-ion batteries are promising candidates as stationary storage systems for power-grid applications due to their high safety and low cost.The practical implementation of Zn-ion batteries currently still face...Aqueous zinc-ion batteries are promising candidates as stationary storage systems for power-grid applications due to their high safety and low cost.The practical implementation of Zn-ion batteries currently still faces formidable challenges because of Zn dendrite growth,hydrogen evolution,and inadequate environmental adaptability.Herein,to address these challenges,a strategy of regulation of water molecules coordination in electrolyte is proposed via developing a cross-linked hydrophilic hydrogel polymer electrolyte.Within this system,the continuous hydrogen bond among H_(2)O molecules is disrupted and the isolated H_(2)O molecules are strongly bound with a polymeric matrix comprised of polyacrylamide,carboxymethyl cellulose,and ethylene glycol,which can restrain the activity of H_(2)O molecules,thus effectively alleviating Zn dendrite growth and hydrogen evolution and enhancing the anti-freezing ability.With this electrolyte,the Zn||Cu cell presents a high coulombic efficiency of 99.4%over 900 cycles and Zn||Zn symmetric cell exhibits high cycling stability,maintaining plating/stripping for over 1,700 h.Moreover,the assembled Zn||PANI device also demonstrates outstanding electrochemical performance over a wide-temperature range,including a long cycling life over 14,120 cycles at room temperature and an ultralong cycling surpassing 30,000 cycles even at−40℃.This showcases the manipulation of water coordination chemistry for advanced,highly adaptable batteries.展开更多
Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important...Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important intermediate product in the reduction of nitrate to ammonia.Therefore,the mechanism of converting nitrite into ammonia warrants further investigation.Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions(NO_(2)^(−)RR).However,designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO_(2)^(−)RR and catalyst design.Herein,we develop a molecular platform of cobalt porphyrin with three coordination microenvironments(Co-N_(3)X_(1),X=N,O,S).Electrochemical experiments demonstrate that cobalt porphyrin with O coordination(CoOTPP)exhibits the lowest onset potential and the highest activity for NO_(2)^(−)RR in ammonia production.Under neutral,nonbuffered conditions over a wide potential range(−1.0 to−1.5 V versus AgCl/Ag),the Faradaic efficiency of nearly 90%for ammonia was achieved and reached 94.5%at−1.4 V versus AgCl/Ag,with an ammonia yield of 6,498μgh^(−1)and a turnover number of 22,869 at−1.5V versus AgCl/Ag.In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field.Therefore,this results in enhanced electrochemical activity for NO_(2)^(−)RR in ammonia production.This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity.展开更多
Carbonic anhydrase accounts for catalytic reaction of CO_(2)/HCO_(3)^(–) transformation, thus resulting in neutralization and acidification of the cellular environment, thereby favoring tumor development. Hence, it i...Carbonic anhydrase accounts for catalytic reaction of CO_(2)/HCO_(3)^(–) transformation, thus resulting in neutralization and acidification of the cellular environment, thereby favoring tumor development. Hence, it is a classical protein model of greatly biocatalytic significance as well as a highly expressed biomarker with renal tumor. We herein proposed a single-molecule measurement on carbonic anhydrase using MspA nanopore, in [BMIM+] and asymmetric K^(+)/Ca^(2+) cationic coordinated environment, instead of usual symmetric KCl/NaCl electrolyte. Significantly, our empirical analysis showed that asymmetric K^(+)/Ca^(2+) cationic environment contributes to distinguishable current modulations, thus yielding better resolution for carbonic anhydrase measurement, which is independent of applied voltage and more importantly, is stable enough at varied pH conditions and for very low concentration test in urine sample. Our results provide a classical model for nanopore protein analysis, and may also permit biocatalytic measurement at single-molecule level.展开更多
Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural un...Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural unstability and slow kinetics.It is difficult to achieve efficient potassium storage with unmodified carbonaceous anode.Herein,atomic bismuth(Bi)sites with different atom coordinations anchored on carbon nanosheets(CNSs)have been synthesized through a template method.The properties of prepared multi-doping carbon anodes Bi-N_(3)S_(1)/CNSs,Bi-N_(3)P_(1)/CNSs and Bi-N_(4)/CNSs were probed in PIBs.The configuration Bi-N_(3)S_(1) with stronger charge asymmetry exhibits superior potassium storage performance compared to Bi-N_(3)P_(1) and Bi-N_(4) configurations.The Bi-N_(3)S_(1)/CNSs display a rate capacity of 129.2 mAh g^(-1)even at 10 A g^(-1)and an impressive cyclability characterized by over 5000 cycles at 5 A g^(-1),on account of its optimal coordination environment with more active Bi centers and K^(+)adsorption sites.Notably,assembled potassium-ion full cell Mg-KVO//Bi-N_(3)S_(1)/CNSs also shows an outstanding cycling stability,enduring 3000 cycles at 2 A g^(-1).Therefore,it can be demonstrated that regulating the electronic structure of metallic centre M-N_(4) via changing the type of ligating atom is a feasible strategy for modifying carbon anodes,on the base of co-doping metal and non-metal.展开更多
Single-atom catalysis has revolutionized heterogeneous catalysis,which offers unparalleled atomic efficiency,well-defined active sites,and unique electronic properties.Unlike traditional nanoparticle catalysts,single-...Single-atom catalysis has revolutionized heterogeneous catalysis,which offers unparalleled atomic efficiency,well-defined active sites,and unique electronic properties.Unlike traditional nanoparticle catalysts,single-atom catalysts(SACs)maximize metal utilization and exhibit distinct catalytic behaviors due to their atomically dispersed nature.Over the past decade,SACs have demonstrated exceptional performance in various electrochemical and thermocatalytic reactions[1–3].However,despite these promising developments,several fundamental challenges hinder their practical implementation and large-scale commercialization.SACs face three major challenges:catalytic activity,stability,and scalable synthesis.Their isolated nature limits multi-electron transfer processes,making reaction kinetics highly sensitive to the coordination environment.To enhance catalytic activity,strategies such as secondary coordination effect,doping,and/or dual-atom configuration can be employed.Stability is another key issue,as single atoms tend to aggregate or undergo oxidation under reaction conditions,leading to performance decay.Strategies like strong metal-support interaction and ligand stabilization can be adopted to improve the durability of SACs.展开更多
Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)o...Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)on OH-and HMF are weak,which limits its further application.Metal defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of biomass.In this work,we prepare Co_(3)O_(4)with metal defects and load the precious metal platinum at the defect sites(PtVco).The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co element.The resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential(1.14 V)and 19 times higher current density than pure Co_(3)O_(4)at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.展开更多
Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development...Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.展开更多
Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic acti...Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic active center for the formation of catalytic products.However,in many cases,the pristine MOFs still exist during the catalytic process,the key role of these pristine MOFs is often ignored in revealing the catalytic mechanism.Here,we designed two Cu(imidazole)with different coordination environments,namely CuN_(2)and Cu_(2)N_(4)for CO_(2)RR.The structures of the two MOFs were still remained after the catalytic reaction.We discovered that the pristine MOFs served as activation catalysts for converting CO_(2)into CO.Sequentially,the Cu-based derivatives,in the two cases,Cu(111)converted the CO into C_(2+)products.The CuN_(2)with more exposed Cu-N centers showed a higher FE_(CO)and a higher final FEC_(2+)than Cu_(2)N_(4).This auto-tandem catalytic mechanism was supported by electrocatalytic performance,TPD-CO,HRTEM,SAED,XPS,in-situ XANES and XES and DFT computation.The auto-tandem catalytic mechanism provides a new route to design Cu-based MOF electrocatalysts for high product selectivity in CO_(2)RR.展开更多
The structural complexity of supported metal catalysts,playing significant role in a wide range of chemical technologies,have prevented us from deeply understanding their catalytic mechanisms at atomic level.A fundame...The structural complexity of supported metal catalysts,playing significant role in a wide range of chemical technologies,have prevented us from deeply understanding their catalytic mechanisms at atomic level.A fundamental understanding of the nature of active sites and structure–performance relationship of supported metal catalysts from a comprehensive view will open up numerous new opportunities for the development of advanced catalysts to address the global challenges in energy conversion and environmental protection.This review surveys the effects of multiple factors,including the metal size,shape,support,alloy and ligand modifier,on the coordinated environment of active center and further their influence on the catalytic reactions,aiming to provide guidance for the design of industrialized heterogeneous catalysts with extraordinary performance.Subsequently,the key structure characterization techniques in determining the coordination structure of active metal sites,especially the dynamic coordination structure change under the reaction condition,are well summarized.A brief summary is finally provided together with personal perspectives on the further development in the field of heterogeneous metal catalysts.展开更多
Rh single atom catalysts(SACs)have been insensitively investigated recently due to the maximum utilization efficiency of Rh,one of the most expensive precious metals.Although great efforts have been made in the develo...Rh single atom catalysts(SACs)have been insensitively investigated recently due to the maximum utilization efficiency of Rh,one of the most expensive precious metals.Although great efforts have been made in the development and application of Rh SACs,there are few reports on the precise control of the local coordination environment of Rh single sites on CeO_(2) and their catalytic performance for N_(2)O decomposition.Herein,Rh/CeO_(2) catalysts with different Rh-O coordination numbers(CNs)were successfully prepared using different CeO_(2) supports and a simple incipient wetness impregnation(IWI)method.It is observed that the Rh/CeO_(2) catalyst with slightly higher CN of Rh-O(Rh/CeO_(2)-H)prepared from CeO_(2) shows much higher N_(2)O decomposition activity than the catalyst with lower CN of Rh-O(Rh/CeO_(2)-L)obtained from Ce(OH)_(x).The Rh species within Rh/CeO_(2)-H are found to be more reactive than those within Rh/CeO_(2)-L,which can better facilitate the O_(2)desorption once formed during N_(2)O deco mposition.In additio n,more surface oxygen vacancies are present on Rh/CeO_(2)-H than on Rh/CeO_(2)-L,well explaining the superior N_(2)O adsorption and activation capability on the former catalyst.It is concluded that more abundant oxygen vacancies and reactive Rh single atom sites with slightly higher CN of Rh-O and significantly higher reducibility altogether contribute to the superior N_(2)O decomposition activity on the Rh/CeO_(2)-H catalyst.展开更多
In this work,DFT calculations were used firstly to simulate the nitrogen coordinated metal single-atom catalysts(M-N_(x)SACs,M=Hg,Cu,Au,and Ru) to predict their catalytic activities in acetylene hydrochlorination.The ...In this work,DFT calculations were used firstly to simulate the nitrogen coordinated metal single-atom catalysts(M-N_(x)SACs,M=Hg,Cu,Au,and Ru) to predict their catalytic activities in acetylene hydrochlorination.The DFT results showed that Ru-N_(x)SACs had the best catalytic performance among the four catalysts,and Ru-N_(x)SACs could effectively inhibit the reduction of ruthenium cation.To verify the DFT results,Ru-N_(x)SACs were fabricated by pyrolyzing MOFs in-situ spatially confined metal precursors.The N coordination environment could be controlled by changing the pyrolysis temperature.Catalytic performance tests indicated that low N coordination number(Ru-N_(2),Ru-N_(3))exhibited excellent catalytic activity and stability compared to RuCl_(3)catalyst.DFT calculations further revealed that Ru-N_(2)and Ru-N_(3)had a tendency to activate HCl at the first step of reaction,whereas Ru-N4tended to activate C_(2)H_(2).These findings will serve as a reference for the design and control of metal active sites.展开更多
Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activit...Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activity.However,the effect of the local coordination environment of Co sites on CO_(2) reduction reaction pathways is still unclear.In this study,we investigated the CO_(2) reduction reaction pathways on Co‐N_(4) sites supported on conjugated N_(4)‐macrocyclic ligands with 1,10‐phenanthroline subunits(Co‐N_(4)‐CPY)by density functional theory calculations.The local coordination environment of single‐atom Co sites with N substituted by O(Co‐N_(3)O‐CPY)and C(Co‐N_(3)C‐CPY)was studied for comparison.The calculation results revealed that both C and O coordination break the symmetry of the primary CoN_(4) ligand field and induce charge redistribution of the Co atom.For Co‐N_(4)‐CPY,CO was confirmed to be the main product of CO_(2)RR.HCOOH is the primary product of Co‐N_(3)O‐CPY because of the greatly increased energy barrier of CO_(2) to*COOH.Although the energy barrier of CO_(2) to*COOH is reduced on Co‐N_(3)C‐CPY,the desorption process of*CO becomes more difficult.CH3OH(or CH_(4))are obtained by further*CO hydrogenation reduction when using Co‐N_(3)C‐CPY.This work provides new insight into the effect of the local coordination environment of single‐atom sites on CO_(2) reduction reaction pathways.展开更多
Aqueous Zn-ion batteries(AZIBs)are the potential options for the next-generation energy storage scenarios due to the cost effectiveness and intrinsic safety.Nevertheless,the industrial application of AZIBs is still im...Aqueous Zn-ion batteries(AZIBs)are the potential options for the next-generation energy storage scenarios due to the cost effectiveness and intrinsic safety.Nevertheless,the industrial application of AZIBs is still impeded by a series of parasitic reactions and dendrites at zinc anodes.In this study,taurine(TAU)is used in electrolyte to simultaneously optimize the coordination condition of the ZnSO4electrolyte and interfacial chemistry at the anode.TAU can preferentially adsorb with the zinc metal and induce an in situ stable and protective interface on the anode,which would avoid the connection between H_(2)O and the zinc metal and promote the even deposition of Zn^(2+).The resulting Zn//Zn batteries achieve more than 3000 hours long cyclic lifespan under 1 mA cm^(-2)and an impressive cumulative capacity at 5 mA cm^(-2).Moreover,Zn//Cu batteries can realize a reversible plating/stripping process over 2,400cycles,with a desirable coulombic efficiency of 99.75%(1 mA cm^(-2)).Additionally,the additive endows Zn//NH_(4)V_(4)O_(10)batteries with more stable cyclic performance and ultrafast rate capability.These capabilities can promote the industrial application of AZIBs.展开更多
Development of high-performance and cost-effective catalysts for electrocatalytic hydrogen evolution reaction(HER)play crucial role in the growing hydrogen economy.Recently,the atomically dispersed metal catalysts hav...Development of high-performance and cost-effective catalysts for electrocatalytic hydrogen evolution reaction(HER)play crucial role in the growing hydrogen economy.Recently,the atomically dispersed metal catalysts have attracted increasing attention due to their ultimate atom utilization and great potential for highly cost-effective and high-efficiency HER electrocatalyst.Herein,we propose a hightemperature treatment strategy to furtherly improve the HER performance of atomically dispersed Ptbased catalyst.Interestingly,after appropriate high-temperature treatment on the atomically dispersed Pt0.8@CN,the Pt species on the designed N-doped porous carbon substrate with rich defect sites can be re-dispersed to single atom state with new coordination environment.The obtained Pt0.8@CN-1000 shows superior HER performance with overpotential of 13 m V at 10 m A cm^(-2)and mass activity of 11,284 m A/mgPtat-0.1 V,much higher than that of the pristine Pt0.8@CN and commercial Pt/C catalyst.The experimental and theoretical investigations indicate that the high-temperature treatment induces the restructuring of coordination environment and then the optimized Pt electronic state leads to the enhanced HER performances.This work affords new strategy and insights to develop the atomically dispersed high-efficiency catalysts.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
Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety o...Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic applications.The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements.Therefore,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic applications.The wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance relationship.In this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted.Finally,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.展开更多
Mn-doped ZnO nanocrystals are synthesized by a wet chemical route and treated in H2/Ar atmosphere with different H2/Ar ratios. It is found that hydrogen annealing could change the coordination environment of Mn in ZnO...Mn-doped ZnO nanocrystals are synthesized by a wet chemical route and treated in H2/Ar atmosphere with different H2/Ar ratios. It is found that hydrogen annealing could change the coordination environment of Mn in ZnO lattice and manipulate the magnetic properties of Mn-doped ZnO. Mn ions initially enter into interstitial sites and a Mn3＋ 06 octahedral coordination is produced in the prepared Mn-doped ZnO sample, in which the nearest neighbor Mn3＋ and 02 ions could form a Mn3＋-O2--Mn3＋ complex. After H2 annealing, interstitial Mn ions can substitute for Zn to generate the Mn2＋O4 tetrahedral coordination in the nanocrystals, in which neighboring Mn2＋ ions and H atoms could form a Mn2＋-O2--Mn2＋ complex and Mn-H-Mn bridge structure. The magnetic measurement of the as-prepared sample shows room temperature paramagnetic behavior due to the Mn3＋-O2--Mn3＋ complex, while the annealed samples exhibit their ferromagnetism, which originates from the Mn-H-Mn bridge structure and the Mn-Mn exchange interaction in the Mn2＋-O2--Mn2＋ complex.展开更多
Atomically dispersed catalysts exhibit significant influence on facilitating the sluggish oxygen reduction reaction(ORR)kinetics with high atom economy,owing to remarkable attributes including nearly 100%atomic utiliz...Atomically dispersed catalysts exhibit significant influence on facilitating the sluggish oxygen reduction reaction(ORR)kinetics with high atom economy,owing to remarkable attributes including nearly 100%atomic utilization and exceptional catalytic functionality.Furthermore,accurately controlling atomic physical properties including spin,charge,orbital,and lattice degrees of atomically dispersed catalysts can realize the optimized chemical properties including maximum atom utilization efficiency,homogenous active centers,and satisfactory catalytic performance,but remains elusive.Here,through physical and chemical insight,we review and systematically summarize the strategies to optimize atomically dispersed ORR catalysts including adjusting the atomic coordination environment,adjacent electronic orbital and site density,and the choice of dual-atom sites.Then the emphasis is on the fundamental understanding of the correlation between the physical property and the catalytic behavior for atomically dispersed catalysts.Finally,an overview of the existing challenges and prospects to illustrate the current obstacles and potential opportunities for the advancement of atomically dispersed catalysts in the realm of electrocatalytic reactions is offered.展开更多
One of the urgent and challenging topics in diversified sustainable energy conversion is the development of high-performance,low-cost,and well durable catalysts.Cu single-atom catalysts(SACs)have become promising cata...One of the urgent and challenging topics in diversified sustainable energy conversion is the development of high-performance,low-cost,and well durable catalysts.Cu single-atom catalysts(SACs)have become promising catalysts for diversified sustainable energy conversion due to their capability to maximize the utilization efficiency,acquire modulated electronic structure and optimized binding strength with intermediates.In this review,we have provided an interview of the recent progress achieved in the field of electrocatalysis,photocatalysis,and heterogeneous reaction based on Cu SACs.Started by this review,we have summarized some advanced synthetic strategies for the construction of Cu SACs.Subsequently,the performance-improving strategies are discussed in terms of the coordination environments of the reaction center,reaction mechanism and selectivity,based on free energy diagram and electron structure analysis.Finally,the remaining issues,challenges,and opportunities of Cu SACs are also provided,affording a perspective for future studies.This review not only offers us a deep understanding on the catalytic mechanism of Cu SACs for energy conversion,but also encourages more endeavors in prompting their practical application.展开更多
基金supported by the Natural Science Foundation of Hebei Province(no.E2024501010)the National Natural Science Foundation of China(no.52374301)+1 种基金the Shijiazhuang Basic Research Project(no.241790667A)the Performance Subsidy Fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(no.22567627H)。
文摘The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge distribution of the traditional M-N_(4)active site,the adsorption energy of the key oxygen intermediates in the process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is difficult to reach the optimal value,which seriously limits the catalytic efficiency.The core of solving this problem lies in the accurate modulation of the coordination environment of the M-N_(4)site,which can realize the breakthrough improvement of the catalytic performance by synergistically optimizing the geometric configuration and electronic structure.In this paper,we systematically analyze the ORR/OER reaction mechanism and then comprehensively review the four main strategies to optimize the coordination environment of M-N-C:metal site regulation,coordination number engineering,non-metal atom doping,and carbon support regulation.Through an in-depth analysis of the structure-activity relationship between the coordination configuration and catalytic performance,the core challenges faced by current research are pointed out,and future research directions are envisioned.This work aims to provide theoretical references for the directional construction of highly efficient M-N-C catalysts with optimized coordination environments.
基金the financial support from Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515012077)National Natural Science Foundation of China(No.52401296)+3 种基金the financial support by Guangdong Provincial Pearl River Talents Program(Grant No.2023CX10L019)Bureau of Science and Technology of Jiangmen Municipality(Grant No.2320002001062)And this work is also partly supported by Guangdong S&T Programme(No.2022B1212040001)Guangdong-Hong Kong-Macao joint Laboratory(No.2023B1212120003).
文摘Aqueous zinc-ion batteries are promising candidates as stationary storage systems for power-grid applications due to their high safety and low cost.The practical implementation of Zn-ion batteries currently still faces formidable challenges because of Zn dendrite growth,hydrogen evolution,and inadequate environmental adaptability.Herein,to address these challenges,a strategy of regulation of water molecules coordination in electrolyte is proposed via developing a cross-linked hydrophilic hydrogel polymer electrolyte.Within this system,the continuous hydrogen bond among H_(2)O molecules is disrupted and the isolated H_(2)O molecules are strongly bound with a polymeric matrix comprised of polyacrylamide,carboxymethyl cellulose,and ethylene glycol,which can restrain the activity of H_(2)O molecules,thus effectively alleviating Zn dendrite growth and hydrogen evolution and enhancing the anti-freezing ability.With this electrolyte,the Zn||Cu cell presents a high coulombic efficiency of 99.4%over 900 cycles and Zn||Zn symmetric cell exhibits high cycling stability,maintaining plating/stripping for over 1,700 h.Moreover,the assembled Zn||PANI device also demonstrates outstanding electrochemical performance over a wide-temperature range,including a long cycling life over 14,120 cycles at room temperature and an ultralong cycling surpassing 30,000 cycles even at−40℃.This showcases the manipulation of water coordination chemistry for advanced,highly adaptable batteries.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFC2105800National Natural Science Foundation of China,Grant/Award Numbers:21901084,21905106,22279041+2 种基金Higher Education Discipline Innovation Project,Grant/Award Number:B17020Specific Research Fund of the Innovation Platform for Academicians of Hainan Province,China,Grant/Award Number:YSPTZX202321Natural Science Foundation of Jilin Province,Grant/Award Number:SKL202302017.
文摘Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energyintensive Haber-Bosch process.Nitrite is an important intermediate product in the reduction of nitrate to ammonia.Therefore,the mechanism of converting nitrite into ammonia warrants further investigation.Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions(NO_(2)^(−)RR).However,designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO_(2)^(−)RR and catalyst design.Herein,we develop a molecular platform of cobalt porphyrin with three coordination microenvironments(Co-N_(3)X_(1),X=N,O,S).Electrochemical experiments demonstrate that cobalt porphyrin with O coordination(CoOTPP)exhibits the lowest onset potential and the highest activity for NO_(2)^(−)RR in ammonia production.Under neutral,nonbuffered conditions over a wide potential range(−1.0 to−1.5 V versus AgCl/Ag),the Faradaic efficiency of nearly 90%for ammonia was achieved and reached 94.5%at−1.4 V versus AgCl/Ag,with an ammonia yield of 6,498μgh^(−1)and a turnover number of 22,869 at−1.5V versus AgCl/Ag.In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field.Therefore,this results in enhanced electrochemical activity for NO_(2)^(−)RR in ammonia production.This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity.
基金National Key Research and Development Program of China(2022YFB3205600)Chongqing Talents:Exceptional Young Talents Project(cstc2021ycjh-bgzxm0016)+1 种基金Beibei Technology Talents and Independent Innovation Project(No.2022-34)the Natural Science Foundation of Chongqing,China(cstc2021jcyj-jqx0030).
文摘Carbonic anhydrase accounts for catalytic reaction of CO_(2)/HCO_(3)^(–) transformation, thus resulting in neutralization and acidification of the cellular environment, thereby favoring tumor development. Hence, it is a classical protein model of greatly biocatalytic significance as well as a highly expressed biomarker with renal tumor. We herein proposed a single-molecule measurement on carbonic anhydrase using MspA nanopore, in [BMIM+] and asymmetric K^(+)/Ca^(2+) cationic coordinated environment, instead of usual symmetric KCl/NaCl electrolyte. Significantly, our empirical analysis showed that asymmetric K^(+)/Ca^(2+) cationic environment contributes to distinguishable current modulations, thus yielding better resolution for carbonic anhydrase measurement, which is independent of applied voltage and more importantly, is stable enough at varied pH conditions and for very low concentration test in urine sample. Our results provide a classical model for nanopore protein analysis, and may also permit biocatalytic measurement at single-molecule level.
基金financially supported by the National Natural Science Foundation of China(22209057)the Guangzhou Basic and Applied Basic Research Foundation(2024A04J0839)。
文摘Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural unstability and slow kinetics.It is difficult to achieve efficient potassium storage with unmodified carbonaceous anode.Herein,atomic bismuth(Bi)sites with different atom coordinations anchored on carbon nanosheets(CNSs)have been synthesized through a template method.The properties of prepared multi-doping carbon anodes Bi-N_(3)S_(1)/CNSs,Bi-N_(3)P_(1)/CNSs and Bi-N_(4)/CNSs were probed in PIBs.The configuration Bi-N_(3)S_(1) with stronger charge asymmetry exhibits superior potassium storage performance compared to Bi-N_(3)P_(1) and Bi-N_(4) configurations.The Bi-N_(3)S_(1)/CNSs display a rate capacity of 129.2 mAh g^(-1)even at 10 A g^(-1)and an impressive cyclability characterized by over 5000 cycles at 5 A g^(-1),on account of its optimal coordination environment with more active Bi centers and K^(+)adsorption sites.Notably,assembled potassium-ion full cell Mg-KVO//Bi-N_(3)S_(1)/CNSs also shows an outstanding cycling stability,enduring 3000 cycles at 2 A g^(-1).Therefore,it can be demonstrated that regulating the electronic structure of metallic centre M-N_(4) via changing the type of ligating atom is a feasible strategy for modifying carbon anodes,on the base of co-doping metal and non-metal.
文摘Single-atom catalysis has revolutionized heterogeneous catalysis,which offers unparalleled atomic efficiency,well-defined active sites,and unique electronic properties.Unlike traditional nanoparticle catalysts,single-atom catalysts(SACs)maximize metal utilization and exhibit distinct catalytic behaviors due to their atomically dispersed nature.Over the past decade,SACs have demonstrated exceptional performance in various electrochemical and thermocatalytic reactions[1–3].However,despite these promising developments,several fundamental challenges hinder their practical implementation and large-scale commercialization.SACs face three major challenges:catalytic activity,stability,and scalable synthesis.Their isolated nature limits multi-electron transfer processes,making reaction kinetics highly sensitive to the coordination environment.To enhance catalytic activity,strategies such as secondary coordination effect,doping,and/or dual-atom configuration can be employed.Stability is another key issue,as single atoms tend to aggregate or undergo oxidation under reaction conditions,leading to performance decay.Strategies like strong metal-support interaction and ligand stabilization can be adopted to improve the durability of SACs.
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2023QB235,ZR202111240183,ZR2021QF120)the Postdoctoral Science Foundation of China(2022M711956)the Taishan Scholar Program of Shandong Province(tsqnz20231216).
文摘Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)on OH-and HMF are weak,which limits its further application.Metal defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of biomass.In this work,we prepare Co_(3)O_(4)with metal defects and load the precious metal platinum at the defect sites(PtVco).The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co element.The resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential(1.14 V)and 19 times higher current density than pure Co_(3)O_(4)at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.
基金supported by the National Natural Science Foundation(52302284,22002086,22204096)Shanghai Sailing Program(23YF1412200)the Fundamental Research Funds for the Central Universities(22120240314).
文摘Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.
基金supported by the National Natural Science Foundation of China(Nos.22174067 and 22204078)the Natural Science Foundation of Jiangsu Province of China(No.BK20220370)+2 种基金Jiangsu Provincial Department of Education(No.22KJB150009)State Key Laboratory of Analytical Chemistry for Life Science(No.SKLACLS2218)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic active center for the formation of catalytic products.However,in many cases,the pristine MOFs still exist during the catalytic process,the key role of these pristine MOFs is often ignored in revealing the catalytic mechanism.Here,we designed two Cu(imidazole)with different coordination environments,namely CuN_(2)and Cu_(2)N_(4)for CO_(2)RR.The structures of the two MOFs were still remained after the catalytic reaction.We discovered that the pristine MOFs served as activation catalysts for converting CO_(2)into CO.Sequentially,the Cu-based derivatives,in the two cases,Cu(111)converted the CO into C_(2+)products.The CuN_(2)with more exposed Cu-N centers showed a higher FE_(CO)and a higher final FEC_(2+)than Cu_(2)N_(4).This auto-tandem catalytic mechanism was supported by electrocatalytic performance,TPD-CO,HRTEM,SAED,XPS,in-situ XANES and XES and DFT computation.The auto-tandem catalytic mechanism provides a new route to design Cu-based MOF electrocatalysts for high product selectivity in CO_(2)RR.
文摘The structural complexity of supported metal catalysts,playing significant role in a wide range of chemical technologies,have prevented us from deeply understanding their catalytic mechanisms at atomic level.A fundamental understanding of the nature of active sites and structure–performance relationship of supported metal catalysts from a comprehensive view will open up numerous new opportunities for the development of advanced catalysts to address the global challenges in energy conversion and environmental protection.This review surveys the effects of multiple factors,including the metal size,shape,support,alloy and ligand modifier,on the coordinated environment of active center and further their influence on the catalytic reactions,aiming to provide guidance for the design of industrialized heterogeneous catalysts with extraordinary performance.Subsequently,the key structure characterization techniques in determining the coordination structure of active metal sites,especially the dynamic coordination structure change under the reaction condition,are well summarized.A brief summary is finally provided together with personal perspectives on the further development in the field of heterogeneous metal catalysts.
基金Project supported by the Startup Fund(F.L.)from the University of Central Florida(UCF)National Science Foundation grants(CHE-1955343,DMR-1920050).
文摘Rh single atom catalysts(SACs)have been insensitively investigated recently due to the maximum utilization efficiency of Rh,one of the most expensive precious metals.Although great efforts have been made in the development and application of Rh SACs,there are few reports on the precise control of the local coordination environment of Rh single sites on CeO_(2) and their catalytic performance for N_(2)O decomposition.Herein,Rh/CeO_(2) catalysts with different Rh-O coordination numbers(CNs)were successfully prepared using different CeO_(2) supports and a simple incipient wetness impregnation(IWI)method.It is observed that the Rh/CeO_(2) catalyst with slightly higher CN of Rh-O(Rh/CeO_(2)-H)prepared from CeO_(2) shows much higher N_(2)O decomposition activity than the catalyst with lower CN of Rh-O(Rh/CeO_(2)-L)obtained from Ce(OH)_(x).The Rh species within Rh/CeO_(2)-H are found to be more reactive than those within Rh/CeO_(2)-L,which can better facilitate the O_(2)desorption once formed during N_(2)O deco mposition.In additio n,more surface oxygen vacancies are present on Rh/CeO_(2)-H than on Rh/CeO_(2)-L,well explaining the superior N_(2)O adsorption and activation capability on the former catalyst.It is concluded that more abundant oxygen vacancies and reactive Rh single atom sites with slightly higher CN of Rh-O and significantly higher reducibility altogether contribute to the superior N_(2)O decomposition activity on the Rh/CeO_(2)-H catalyst.
基金supported by the National Natural Science Foundation of China (NSFC,22172082,21978137,22102074,and 21878162)Natural Science Foundation of Tianjin (20JCZDJC00770)+1 种基金Postdoctoral Research Foundation of China (2021M701776)NCC Fund (NCC2020FH05)。
文摘In this work,DFT calculations were used firstly to simulate the nitrogen coordinated metal single-atom catalysts(M-N_(x)SACs,M=Hg,Cu,Au,and Ru) to predict their catalytic activities in acetylene hydrochlorination.The DFT results showed that Ru-N_(x)SACs had the best catalytic performance among the four catalysts,and Ru-N_(x)SACs could effectively inhibit the reduction of ruthenium cation.To verify the DFT results,Ru-N_(x)SACs were fabricated by pyrolyzing MOFs in-situ spatially confined metal precursors.The N coordination environment could be controlled by changing the pyrolysis temperature.Catalytic performance tests indicated that low N coordination number(Ru-N_(2),Ru-N_(3))exhibited excellent catalytic activity and stability compared to RuCl_(3)catalyst.DFT calculations further revealed that Ru-N_(2)and Ru-N_(3)had a tendency to activate HCl at the first step of reaction,whereas Ru-N4tended to activate C_(2)H_(2).These findings will serve as a reference for the design and control of metal active sites.
文摘Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activity.However,the effect of the local coordination environment of Co sites on CO_(2) reduction reaction pathways is still unclear.In this study,we investigated the CO_(2) reduction reaction pathways on Co‐N_(4) sites supported on conjugated N_(4)‐macrocyclic ligands with 1,10‐phenanthroline subunits(Co‐N_(4)‐CPY)by density functional theory calculations.The local coordination environment of single‐atom Co sites with N substituted by O(Co‐N_(3)O‐CPY)and C(Co‐N_(3)C‐CPY)was studied for comparison.The calculation results revealed that both C and O coordination break the symmetry of the primary CoN_(4) ligand field and induce charge redistribution of the Co atom.For Co‐N_(4)‐CPY,CO was confirmed to be the main product of CO_(2)RR.HCOOH is the primary product of Co‐N_(3)O‐CPY because of the greatly increased energy barrier of CO_(2) to*COOH.Although the energy barrier of CO_(2) to*COOH is reduced on Co‐N_(3)C‐CPY,the desorption process of*CO becomes more difficult.CH3OH(or CH_(4))are obtained by further*CO hydrogenation reduction when using Co‐N_(3)C‐CPY.This work provides new insight into the effect of the local coordination environment of single‐atom sites on CO_(2) reduction reaction pathways.
基金supported by the State Key Laboratorys of Electrical Insulation and Power Equipment(EIPE23308)the Young Talent Recruiting Plans of Xi’an Jiaotong University(DQ6J012)+2 种基金the Fundamental Research Funds for the Central Universities(xtr042021008,xzy022022049)the Natural Science Basic Research Plan in Shaanxi Province of China(2023-JC-QN-0587)the“Young Talent Support Plan”of Xi’an Jiaotong University。
文摘Aqueous Zn-ion batteries(AZIBs)are the potential options for the next-generation energy storage scenarios due to the cost effectiveness and intrinsic safety.Nevertheless,the industrial application of AZIBs is still impeded by a series of parasitic reactions and dendrites at zinc anodes.In this study,taurine(TAU)is used in electrolyte to simultaneously optimize the coordination condition of the ZnSO4electrolyte and interfacial chemistry at the anode.TAU can preferentially adsorb with the zinc metal and induce an in situ stable and protective interface on the anode,which would avoid the connection between H_(2)O and the zinc metal and promote the even deposition of Zn^(2+).The resulting Zn//Zn batteries achieve more than 3000 hours long cyclic lifespan under 1 mA cm^(-2)and an impressive cumulative capacity at 5 mA cm^(-2).Moreover,Zn//Cu batteries can realize a reversible plating/stripping process over 2,400cycles,with a desirable coulombic efficiency of 99.75%(1 mA cm^(-2)).Additionally,the additive endows Zn//NH_(4)V_(4)O_(10)batteries with more stable cyclic performance and ultrafast rate capability.These capabilities can promote the industrial application of AZIBs.
基金financially supported by the National Science Foundation of China(21773112,21173119,and 21273109)the National Key Technology R&D Program of China(2017YFB0310704)the Fundamental Research Funds for the Central Universities and the Hubei Key Laboratory for Processing and Application of Catalytic Materials(CH201401)。
文摘Development of high-performance and cost-effective catalysts for electrocatalytic hydrogen evolution reaction(HER)play crucial role in the growing hydrogen economy.Recently,the atomically dispersed metal catalysts have attracted increasing attention due to their ultimate atom utilization and great potential for highly cost-effective and high-efficiency HER electrocatalyst.Herein,we propose a hightemperature treatment strategy to furtherly improve the HER performance of atomically dispersed Ptbased catalyst.Interestingly,after appropriate high-temperature treatment on the atomically dispersed Pt0.8@CN,the Pt species on the designed N-doped porous carbon substrate with rich defect sites can be re-dispersed to single atom state with new coordination environment.The obtained Pt0.8@CN-1000 shows superior HER performance with overpotential of 13 m V at 10 m A cm^(-2)and mass activity of 11,284 m A/mgPtat-0.1 V,much higher than that of the pristine Pt0.8@CN and commercial Pt/C catalyst.The experimental and theoretical investigations indicate that the high-temperature treatment induces the restructuring of coordination environment and then the optimized Pt electronic state leads to the enhanced HER performances.This work affords new strategy and insights to develop the atomically dispersed high-efficiency catalysts.
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the National Natural Science Foundation of China(Nos.21805191 and 21972094)the Guangdong Basic and Applied Basic Research Founda-tion(No.2020A1515010982)+1 种基金Shenzhen Pengcheng Scholar Program,Shenzhen Peacock Plan(No.KQTD2016053112042971)Shenzhen Science and Technology Program(Nos.KQJSCX20170727100802505 and RCJC20200714114434086).
文摘Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic applications.The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements.Therefore,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic applications.The wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance relationship.In this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted.Finally,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.
基金supported by the National Basic Research Program of China(Grant No.2013CB934001)the National Natural Science Foundation of China(Grant Nos.51072012 and 51272015)
文摘Mn-doped ZnO nanocrystals are synthesized by a wet chemical route and treated in H2/Ar atmosphere with different H2/Ar ratios. It is found that hydrogen annealing could change the coordination environment of Mn in ZnO lattice and manipulate the magnetic properties of Mn-doped ZnO. Mn ions initially enter into interstitial sites and a Mn3＋ 06 octahedral coordination is produced in the prepared Mn-doped ZnO sample, in which the nearest neighbor Mn3＋ and 02 ions could form a Mn3＋-O2--Mn3＋ complex. After H2 annealing, interstitial Mn ions can substitute for Zn to generate the Mn2＋O4 tetrahedral coordination in the nanocrystals, in which neighboring Mn2＋ ions and H atoms could form a Mn2＋-O2--Mn2＋ complex and Mn-H-Mn bridge structure. The magnetic measurement of the as-prepared sample shows room temperature paramagnetic behavior due to the Mn3＋-O2--Mn3＋ complex, while the annealed samples exhibit their ferromagnetism, which originates from the Mn-H-Mn bridge structure and the Mn-Mn exchange interaction in the Mn2＋-O2--Mn2＋ complex.
基金supported by the National Natural Science Foundation of China(22234005,21974070)the Natural Science Foundation of Jiangsu Province(BK20222015)。
文摘Atomically dispersed catalysts exhibit significant influence on facilitating the sluggish oxygen reduction reaction(ORR)kinetics with high atom economy,owing to remarkable attributes including nearly 100%atomic utilization and exceptional catalytic functionality.Furthermore,accurately controlling atomic physical properties including spin,charge,orbital,and lattice degrees of atomically dispersed catalysts can realize the optimized chemical properties including maximum atom utilization efficiency,homogenous active centers,and satisfactory catalytic performance,but remains elusive.Here,through physical and chemical insight,we review and systematically summarize the strategies to optimize atomically dispersed ORR catalysts including adjusting the atomic coordination environment,adjacent electronic orbital and site density,and the choice of dual-atom sites.Then the emphasis is on the fundamental understanding of the correlation between the physical property and the catalytic behavior for atomically dispersed catalysts.Finally,an overview of the existing challenges and prospects to illustrate the current obstacles and potential opportunities for the advancement of atomically dispersed catalysts in the realm of electrocatalytic reactions is offered.
基金financially supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_2795)the Basic Science(Natural Science)Research Project of Colleges and Universities of Jiangsu Province(No.21KJB540001)Changzhou Sci&Tech Program(Nos.CJ20220180,CJ20210042),China.
文摘One of the urgent and challenging topics in diversified sustainable energy conversion is the development of high-performance,low-cost,and well durable catalysts.Cu single-atom catalysts(SACs)have become promising catalysts for diversified sustainable energy conversion due to their capability to maximize the utilization efficiency,acquire modulated electronic structure and optimized binding strength with intermediates.In this review,we have provided an interview of the recent progress achieved in the field of electrocatalysis,photocatalysis,and heterogeneous reaction based on Cu SACs.Started by this review,we have summarized some advanced synthetic strategies for the construction of Cu SACs.Subsequently,the performance-improving strategies are discussed in terms of the coordination environments of the reaction center,reaction mechanism and selectivity,based on free energy diagram and electron structure analysis.Finally,the remaining issues,challenges,and opportunities of Cu SACs are also provided,affording a perspective for future studies.This review not only offers us a deep understanding on the catalytic mechanism of Cu SACs for energy conversion,but also encourages more endeavors in prompting their practical application.
