Dual-metal single-atom catalysts(DACs),featuring high atomic utilization efficiency,excellent selectivity,and stability originating from the atomically dispersed nature,have emerged as a new frontier in heterogeneous ...Dual-metal single-atom catalysts(DACs),featuring high atomic utilization efficiency,excellent selectivity,and stability originating from the atomically dispersed nature,have emerged as a new frontier in heterogeneous electrocatalysis due to the synergistic effect between diversified metal active sites in promoting their catalytic activity.In this review,the recent progress and development on the syntheses,characterizations,theoretical uniqueness,and applications for various catalytic reactions and devices(oxygen reduction reaction,oxygen evolution reaction,hydrogen evolution reaction,CO_(2) reduction reaction,N2 reduction reaction,proton exchange membrane fuel cells)are summarized and reviewed.Specifically,the synergistic effect between the two metal centers and electronic structures of catalysts is systematically discussed.Moreover,the future challenges and prospects in developing practical DACs are proposed as a possible direction for further investigation.展开更多
The synergy effect between different components has attracted widespread attentions because of improved activity, selectivity and stability than single component. In this paper, we fabricated mesoporous hybrid dual-me...The synergy effect between different components has attracted widespread attentions because of improved activity, selectivity and stability than single component. In this paper, we fabricated mesoporous hybrid dual-metal Co and Fe containing metallic organic framework（Co/Fe-MOF）, Fe-MOF,and Co-MOF in the ionic liquid（IL）/supercritical CO2（SC）/surfactant emulsion system, and then studied the electrochemical properties of the three MOFs systematically. Experiment results indicate that, by taking advantages of coexistence of double metal, hybrid bi-metal Co/Fe-MOF exhibits the highest specific capacitance and the best cycling stability, with specific capacitance to 319.5 F/g at 1 A/g, 1.4 and 4 times for single Co-MOF and Fe-MOF, respectively.展开更多
Carbon-based dual-metal sites catalysts(DMSCs)have emerged as a new frontier in the field of sustainable energy due to their unique coordination environments,electronic structure,the maximized atom utilization.The rea...Carbon-based dual-metal sites catalysts(DMSCs)have emerged as a new frontier in the field of sustainable energy due to their unique coordination environments,electronic structure,the maximized atom utilization.The reasonable utilization of carbonbased DMSCs provides new possibilities to achieve the outstanding catalytic performance,remarkable selectivity,recyclability in energy-related catalysis.Based on this,this review intends to summarize the recent breakthroughs in carbonbased DMSCs for the energy catalysis.Firstly,the definition and classifications of DMSCs are proposed,mainly dividing into three types(isolated dual-metal site pairs,binuclear homologous dual-metal sites pairs,binuclear heterologous dual-metal sites pairs).Subsequently,we discuss the potential of DMSCs targeting on energy conversion reactions,such as electrocatalytic hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),CO_(2)reduction reaction(CO_(2)RR),N_(2) reduction reaction(NRR).Finally,we predict the remaining challenges and possible opportunities on the unique carbon-based DMSCs for energy applications in the future.展开更多
Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surfa...Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.展开更多
After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordinati...After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.展开更多
The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hyd...The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ORRs.Herein,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in ORR.Electrochemical tests confirm that the introduction of Cu NPs improves the ORR performance greatly.The obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V vs.reversible hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/C.Moreover,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)O.This work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.展开更多
Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications.State of the art in the field is currently a two-st...Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications.State of the art in the field is currently a two-step process:a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition(CVD)followed by delicate layer transfer onto device-relevant substrates.Here,we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area,high quality,and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer process.Carbon(C)ion implantation was performed on Cu-Ni film deposited on a variety of device-relevant substrates.A well-controlled number of layers of graphene,primarily monolayer and bilayer,is precisely controlled by the equivalent fluence of the implanted C-atoms(1 monolayer~4×10^(15)C-atoms/cm^(2)).Upon thermal annealing to promote Cu-Ni alloying,the pre-implanted C-atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C-solubility in Cu.As a result,the expelled C-atoms precipitate into a graphene structure at the interface facilitated by the Cu-like alloy catalysis.After removing the alloyed Cu-like surface layer,the layer-tunable graphene on the desired substrate is directly realized.The layer-selectivity,high quality,and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene films.Molecular dynamics(MD)simulations using the reactive force field(ReaxFF)were performed to elucidate the graphene formation mechanisms in this novel synthesis approach.With the wide use of ion implantation technology in the microelectronics展开更多
Constructing atomically dispersed active sites with densely exposed and dispersed double metal-Sx catalytic sites for favorable OER catalytic activity remains rare and challenging.Herein,we design and construct a Fe_(...Constructing atomically dispersed active sites with densely exposed and dispersed double metal-Sx catalytic sites for favorable OER catalytic activity remains rare and challenging.Herein,we design and construct a Fe_(1)S_(x)@Co_(3)S_(4) electrocatalyst with Fe single atoms epitaxially confined in Co_(3)S_(4) nanosheets for catalyzing the sluggish alkaline oxygen evolution reaction(OER).Consequently,in ultralow concentration alkaline solutions(0.1 mol/L KOH),such a catalyst is highly active and robust for OER with low overpotentials of 300 and 333 mV at current densities of 10 and 30 mA/cm^(2),respectively,accompanying long-term stability without significant degradation even for 350 h.In addition,Fe_(1)S_(x)@Co_(3)S_(4) shows a turnover frequency(TOF)value of 0.18 s−1,nearly three times that of Co_(3)S_(4)(0.07 s−1),suggesting the higher atomic utilization of Fe single atoms.Mössbauer and in-situ Raman spectra confirm that the OER activity of Fe_(1)S_(x)@Co_(3)S_(4) origins from a thin catalytic layer of Co(Fe)OOH that interacts with trace-level Fe species in the electrolyte,creating dynamically stable active sites.Combined with experimental characterizations,it suggests that the most active S-coordinated dual-metal site configurations are 2S-bridged(Fe-Co)S4,in which Co-S and Fe-S moieties are shared with two S atoms,which can strongly regulate the adsorption energy of reaction intermediates,accelerating the OER reaction kinetics.展开更多
Replacement of enzymes with nanomaterials such as atomically dispersed metal catalysts is one of the most crucial steps in addressing the challenges in biocataiysis.Despite the breakthroughs of single-atom catalysts i...Replacement of enzymes with nanomaterials such as atomically dispersed metal catalysts is one of the most crucial steps in addressing the challenges in biocataiysis.Despite the breakthroughs of single-atom catalysts in enzyme-mimicking,a fundamental investigation on the development of an instructional strategy is still required for mimicking biatomic/multiatomic active sites in natural enzymes and constructing synergistically enhanced metal atom active sites.Herein,Fe_(2)NC catalysts with atomically dispersed Fe-Fe dual-sites supported by the metal-organic frameworks-derived nitrogen-doped carbon are employed as biomimetic catalysts to perform proof-of-concept investigation.The effect of Fe atom number toward typical oxidase(cytochrome C oxidase,NADH oxidase,and ascorbic acid oxidase)and peroxidase(NADH peroxidase and ascorbic acid peroxidase)activities is systematically evaluated by experimental and theoretical investigations.A peroxo-like O_(2) adsorption in Fe_(2)NC nanozymes could accelerate the O-O activation and thus achieve the enhanced enzyme-like activities.This work achieves the vivid simulation of the enzyme active sites and provides the theoretical basis for the design of high-performance nanozymes.As a concept application,a colorimetric biosensor for the detection of S^(2-) in tap water is established based on the inhibition of enzyme-like activity of Fe_(2)NC nanozymes.展开更多
The present work gives some insight into the subthreshold behaviour of short-channel double-material- gate strained-silicon on silicon-germanium MOSFETs in terms of subthreshold swing and off-current. The formu- latio...The present work gives some insight into the subthreshold behaviour of short-channel double-material- gate strained-silicon on silicon-germanium MOSFETs in terms of subthreshold swing and off-current. The formu- lation of subthreshold current and, thereupon, the subthreshold swing have been done by exploiting the expression of potential distribution in the channel region of the device. The dependence of the subthreshold characteristics on the device parameters, such as Ge mole fraction, gate length ratio, work function of control gate metal and gate length, has been tested in detail. The analytical models have been validated by the numerical simulation results that were obtained from the device simulation software ATLASTM by Silvaco Inc.展开更多
The development of highly active,selective,and stable electrocatalysts can facilitate the effective implementation of electrocatalytic CO_(2)conversion into fuels or chemicals for mitigating the energy crisis and clim...The development of highly active,selective,and stable electrocatalysts can facilitate the effective implementation of electrocatalytic CO_(2)conversion into fuels or chemicals for mitigating the energy crisis and climate problems.Therefore,it is necessary to achieve the goal through reasonable material design based on the actuality of the operational active site at the molecular scale.Inspired by the stimulating synergistic effect of coupled heteronuclear metal atoms,a novel Ni-Co atomic pairs configuration(denoted as NiN_(3)?CoN_(3)-NC)active site was theoretically screened out for improving electrochemical CO_(2)reduction reaction(CO_(2)RR).The structure of NiN_(3)?CoN_(3)-NC was finely regulated by adjusting Zn content in the precursors Zn/Co/Ni-zeolite imidazolate frameworks(Zn/Co/Ni-ZIFs)and pyrolysis temperature.The structural features of NiN_(3)?CoN_(3)-NC were systematically confirmed by aberration-corrected HAADF-STEM coupled with 3D atom-overlapping Gaussian-function fitting mapping,XAFS,and XRD.The results of theoretical calculations reveal that the synergistic effect of Ni-Co atomic pairs can effectively promote the*COOH intermediate formation and thus the overall CO_(2)RR kinetic was improved,and also restrained the competitive hydrogen evolution reaction.Due to the attributes of Ni-Co atomic pairs configuration,the developed NiN_(3)?CoN_(3)-NC with superior catalytic activity,selectivity,and durability,with a high turnover frequency of 2265 h^(-1)at-1.1 V(vs.RHE)and maximum Faradaic efficiency of 97.7%for CO production.This work demonstrates the great potential of DACs as highly efficient catalysts for CO_(2)RR,provides a useful strategy to design heteronuclear DACs,exploits the synergistic effect of multiple metal sites to facilitate complex CO_(2)RR catalytic reactions,and inspires more efforts to develop the potential of DACs in various fields.展开更多
The activation and reduction of N_(2)to produce ammonia under mild conditions is of great interest,but challenges remain.Here,we report a breakthrough in efficient dinitrogen cleavage by employing small Ptn+(n=1–4)cl...The activation and reduction of N_(2)to produce ammonia under mild conditions is of great interest,but challenges remain.Here,we report a breakthrough in efficient dinitrogen cleavage by employing small Ptn+(n=1–4)clusters and convenient plasma assistance.The reactivity of Pt3+is found to be substantially higher than that of other clusters,and the formed Pt3N7+shows prominent mass abundance among the odd-nitrogen products.We illustrate that a chain reaction path within dual cluster cooperation,especially via a“3+2”mode,is beneficial to N≡N triple bond dissociation,embodying efficient synergistic catalysis.A key intermediate containing a bridged N_(2)of binding with two Pt clusters facilitates N_(2)activation with significantly enhanced interactions between the d orbitals of Pt and the antibondingπ*-orbitals of N_(2).Furthermore,by reacting the Pt_(n)N_(m)+clusters with H_(2),we observed hydrogenation products of both evenand odd-hydrogen species,indicative of ammonia release.The in situ synthesized platinum nitride clusters,typically Pt_(3)N_(7)+,induce a highly active N site for hydrogen anchoring,enabling a cost-effective hydrotreating process for ammonia synthesis.展开更多
Water electrolysis is regarded as an environmental friendly and effective technique for large-scale hydrogen(H2)production[1,2].To date,Pt-based electrocatalysts are still the most efficient HER catalysts[3].However,t...Water electrolysis is regarded as an environmental friendly and effective technique for large-scale hydrogen(H2)production[1,2].To date,Pt-based electrocatalysts are still the most efficient HER catalysts[3].However,the prohibitive cost and scarcity of precious metal catalysts have restricted its large-scale applications.Thus,finding an earth-abundant and effective alternative electrocatalysts is crucial to the development of‘hydrogen economy'.展开更多
The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological en...The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological environment.In this work,ciprofloxacin(CIP)was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater.The sodium alginate(SA)gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe^(3+)and Mn^(2+)as cross-linking agents.Preparation conditions such as metal ions concentration,mass fraction of SA,polymerization temperature and dual-metal ions as crosslinking agent were optimized.Moreover,the effects of operating conditions such as initial concentration of CIP,pH value and catalyst dosage on CIP removal were studied.The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics,and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics.The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles.The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:52171199。
文摘Dual-metal single-atom catalysts(DACs),featuring high atomic utilization efficiency,excellent selectivity,and stability originating from the atomically dispersed nature,have emerged as a new frontier in heterogeneous electrocatalysis due to the synergistic effect between diversified metal active sites in promoting their catalytic activity.In this review,the recent progress and development on the syntheses,characterizations,theoretical uniqueness,and applications for various catalytic reactions and devices(oxygen reduction reaction,oxygen evolution reaction,hydrogen evolution reaction,CO_(2) reduction reaction,N2 reduction reaction,proton exchange membrane fuel cells)are summarized and reviewed.Specifically,the synergistic effect between the two metal centers and electronic structures of catalysts is systematically discussed.Moreover,the future challenges and prospects in developing practical DACs are proposed as a possible direction for further investigation.
基金financially supported by the National Natural Science Foundation of China (Nos. 21571157, U1604123 and 51173170)outstanding Young Talent Research Fund of Zhengzhou University (No. 1521320001)the Open Project Foundation of Key Laboratory of Advanced Energy Materials Chemistry of Nankai University
文摘The synergy effect between different components has attracted widespread attentions because of improved activity, selectivity and stability than single component. In this paper, we fabricated mesoporous hybrid dual-metal Co and Fe containing metallic organic framework（Co/Fe-MOF）, Fe-MOF,and Co-MOF in the ionic liquid（IL）/supercritical CO2（SC）/surfactant emulsion system, and then studied the electrochemical properties of the three MOFs systematically. Experiment results indicate that, by taking advantages of coexistence of double metal, hybrid bi-metal Co/Fe-MOF exhibits the highest specific capacitance and the best cycling stability, with specific capacitance to 319.5 F/g at 1 A/g, 1.4 and 4 times for single Co-MOF and Fe-MOF, respectively.
基金the National Natural Science Foundation of China(Nos.22201262 and 52201261)the Natural Science Foundation of Henan Province(No.222300420290)the China Postdoctoral Science Foundation(No.2021M702939).
文摘Carbon-based dual-metal sites catalysts(DMSCs)have emerged as a new frontier in the field of sustainable energy due to their unique coordination environments,electronic structure,the maximized atom utilization.The reasonable utilization of carbonbased DMSCs provides new possibilities to achieve the outstanding catalytic performance,remarkable selectivity,recyclability in energy-related catalysis.Based on this,this review intends to summarize the recent breakthroughs in carbonbased DMSCs for the energy catalysis.Firstly,the definition and classifications of DMSCs are proposed,mainly dividing into three types(isolated dual-metal site pairs,binuclear homologous dual-metal sites pairs,binuclear heterologous dual-metal sites pairs).Subsequently,we discuss the potential of DMSCs targeting on energy conversion reactions,such as electrocatalytic hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),CO_(2)reduction reaction(CO_(2)RR),N_(2) reduction reaction(NRR).Finally,we predict the remaining challenges and possible opportunities on the unique carbon-based DMSCs for energy applications in the future.
基金supported by the National Science Fund for Distinguished Young Scholars(52125309)the National Natural Science Foundation of China(51991343,51920105002,51991340,52188101,and 11974156)+3 种基金Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341 and 2019ZT08C044)the Bureau of Industry and Information Technology of Shenzhen for the “2017 Graphene Manufacturing Innovation Center Project”(201901171523)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20190809180605522)Shenzhen Science and Technology Program(KQTD20190929173815000 and 20200925161102001)。
文摘Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.
基金supported by the National Key Research and Development Program of China(Nos.2021YFF1200700 and 2021YFF1200701)the National Natural Science Foundation of China(Nos.91859101,81971744,U1932107,82001952,11804248,82302361,and 82302381)+5 种基金Outstanding Youth Funds of Tianjin(No.2021FJ-0009)STI 2030-Major Projects(No.2022ZD0210200)National Natural Science Foundation of Tianjin(Nos.19JCZDJC34000,20JCYBJC00940,21JCYBJC00550,21JCZDJC00620,and 21JCYBJC00490)the Key Projects of Tianjin Natural Fund(No.21JCZDJC00490)the Innovation Foundation of Tianjin University,China Postdoctoral Science Foundation(No.2023M732601)CAS Interdisciplinary Innovation Team(No.JCTD-2020-08).
文摘After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.
基金supported by the National Key Research and Development Program of China(2021YFA1501500 and 2018YFA0704502)the National Natural Science Foundation of China(22171265,22201286,22033008 and 22220102005)+2 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ103)the Open Research Fund of CNMGE Platform&NSCC-TJthe Open Science Promotion Plan 2023 of CSTCloud。
文摘The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ORRs.Herein,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in ORR.Electrochemical tests confirm that the introduction of Cu NPs improves the ORR performance greatly.The obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V vs.reversible hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/C.Moreover,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)O.This work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.
基金supported by the National Key R&D Program of China(No.2022YFA1203400)the National Natural Science Foundation of China under Grant(Nos.62174093 and 12075307)+7 种基金the Ningbo Youth Science and Technology Innovation Leading Talent Project under Grant(No.2023QL006)the Open Research Fund of China National Key Laboratory of Materials for Integrated Circuits(No.NKLJC-K2023-01)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110628)the support by LDRD Seedling ER project at Los Alamos National Laboratory,NM,USA(No.20210867ER)partially supported by Guangdong Provincial Key Laboratory of Computational Science and Material Design(No.2019B030301001)supported by Center for Computational Science and Engineering at Southern University of Science and TechnologyShanghai Rising-Star Program(No.21QA1410900)the support from the Youth Innovation Promotion Association CAS
文摘Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications.State of the art in the field is currently a two-step process:a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition(CVD)followed by delicate layer transfer onto device-relevant substrates.Here,we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area,high quality,and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer process.Carbon(C)ion implantation was performed on Cu-Ni film deposited on a variety of device-relevant substrates.A well-controlled number of layers of graphene,primarily monolayer and bilayer,is precisely controlled by the equivalent fluence of the implanted C-atoms(1 monolayer~4×10^(15)C-atoms/cm^(2)).Upon thermal annealing to promote Cu-Ni alloying,the pre-implanted C-atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C-solubility in Cu.As a result,the expelled C-atoms precipitate into a graphene structure at the interface facilitated by the Cu-like alloy catalysis.After removing the alloyed Cu-like surface layer,the layer-tunable graphene on the desired substrate is directly realized.The layer-selectivity,high quality,and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene films.Molecular dynamics(MD)simulations using the reactive force field(ReaxFF)were performed to elucidate the graphene formation mechanisms in this novel synthesis approach.With the wide use of ion implantation technology in the microelectronics
基金National Natural Science Foundation of China(Nos.21501096,22075223)Natural Science Foundation of Jiangsu Province,China(Nos.BK20150086,BK20201120)+4 种基金Foundation of the Jiangsu Education Committee,China(No.15KJB150020)Six Talent Peaks Project in Jiangsu Province,China(No.JY-087)Innovation Project of Jiangsu Province,Excellent Scientific and Technological Innovation Team of Colleges and Universities of Jiangsu Province,China(No.SUJIAOKE 2021 No.1)Key Subject of Ecology of Jiangsu Province,China(No.SUJIAOYANHAN 2022 No.2)Project of the Scientific and Technological Innovation Team of Nanjing,China(No.NINGJIAOGAOSHI 2021 No.16).
文摘Constructing atomically dispersed active sites with densely exposed and dispersed double metal-Sx catalytic sites for favorable OER catalytic activity remains rare and challenging.Herein,we design and construct a Fe_(1)S_(x)@Co_(3)S_(4) electrocatalyst with Fe single atoms epitaxially confined in Co_(3)S_(4) nanosheets for catalyzing the sluggish alkaline oxygen evolution reaction(OER).Consequently,in ultralow concentration alkaline solutions(0.1 mol/L KOH),such a catalyst is highly active and robust for OER with low overpotentials of 300 and 333 mV at current densities of 10 and 30 mA/cm^(2),respectively,accompanying long-term stability without significant degradation even for 350 h.In addition,Fe_(1)S_(x)@Co_(3)S_(4) shows a turnover frequency(TOF)value of 0.18 s−1,nearly three times that of Co_(3)S_(4)(0.07 s−1),suggesting the higher atomic utilization of Fe single atoms.Mössbauer and in-situ Raman spectra confirm that the OER activity of Fe_(1)S_(x)@Co_(3)S_(4) origins from a thin catalytic layer of Co(Fe)OOH that interacts with trace-level Fe species in the electrolyte,creating dynamically stable active sites.Combined with experimental characterizations,it suggests that the most active S-coordinated dual-metal site configurations are 2S-bridged(Fe-Co)S4,in which Co-S and Fe-S moieties are shared with two S atoms,which can strongly regulate the adsorption energy of reaction intermediates,accelerating the OER reaction kinetics.
基金support of National Natural Science Foundation of China(Nos.22074049,22004042,and 21503273)the Fundamental Research Funds for the Central Universities(Nos.CCNU20QN007 and CCNU20TS013the Program of Introducing Talents of Discipline to Universities of China(Nos.111 program and B17019).
文摘Replacement of enzymes with nanomaterials such as atomically dispersed metal catalysts is one of the most crucial steps in addressing the challenges in biocataiysis.Despite the breakthroughs of single-atom catalysts in enzyme-mimicking,a fundamental investigation on the development of an instructional strategy is still required for mimicking biatomic/multiatomic active sites in natural enzymes and constructing synergistically enhanced metal atom active sites.Herein,Fe_(2)NC catalysts with atomically dispersed Fe-Fe dual-sites supported by the metal-organic frameworks-derived nitrogen-doped carbon are employed as biomimetic catalysts to perform proof-of-concept investigation.The effect of Fe atom number toward typical oxidase(cytochrome C oxidase,NADH oxidase,and ascorbic acid oxidase)and peroxidase(NADH peroxidase and ascorbic acid peroxidase)activities is systematically evaluated by experimental and theoretical investigations.A peroxo-like O_(2) adsorption in Fe_(2)NC nanozymes could accelerate the O-O activation and thus achieve the enhanced enzyme-like activities.This work achieves the vivid simulation of the enzyme active sites and provides the theoretical basis for the design of high-performance nanozymes.As a concept application,a colorimetric biosensor for the detection of S^(2-) in tap water is established based on the inhibition of enzyme-like activity of Fe_(2)NC nanozymes.
文摘The present work gives some insight into the subthreshold behaviour of short-channel double-material- gate strained-silicon on silicon-germanium MOSFETs in terms of subthreshold swing and off-current. The formu- lation of subthreshold current and, thereupon, the subthreshold swing have been done by exploiting the expression of potential distribution in the channel region of the device. The dependence of the subthreshold characteristics on the device parameters, such as Ge mole fraction, gate length ratio, work function of control gate metal and gate length, has been tested in detail. The analytical models have been validated by the numerical simulation results that were obtained from the device simulation software ATLASTM by Silvaco Inc.
基金the support of the Sichuan Science and Technology Program(2023NSFC0098)the Science and Technology Development Fund from Macao SAR(FDCT)(0081/2019/AMJ,0154/2019/A3,006/2022/ALC,and 0111/2022/A2)+2 种基金the Shenzhen-Hong Kong-Macao Science and Technology Research Programme(Type C)(SGDX20210823103803017)the Multi-Year Research Grants(MYRG2022-00026-IAPME)from Research&Development Office at University of Macaothe Frontier Project of Chengdu Tianfu New Area Institute(SWUST,2022ZY017)。
文摘The development of highly active,selective,and stable electrocatalysts can facilitate the effective implementation of electrocatalytic CO_(2)conversion into fuels or chemicals for mitigating the energy crisis and climate problems.Therefore,it is necessary to achieve the goal through reasonable material design based on the actuality of the operational active site at the molecular scale.Inspired by the stimulating synergistic effect of coupled heteronuclear metal atoms,a novel Ni-Co atomic pairs configuration(denoted as NiN_(3)?CoN_(3)-NC)active site was theoretically screened out for improving electrochemical CO_(2)reduction reaction(CO_(2)RR).The structure of NiN_(3)?CoN_(3)-NC was finely regulated by adjusting Zn content in the precursors Zn/Co/Ni-zeolite imidazolate frameworks(Zn/Co/Ni-ZIFs)and pyrolysis temperature.The structural features of NiN_(3)?CoN_(3)-NC were systematically confirmed by aberration-corrected HAADF-STEM coupled with 3D atom-overlapping Gaussian-function fitting mapping,XAFS,and XRD.The results of theoretical calculations reveal that the synergistic effect of Ni-Co atomic pairs can effectively promote the*COOH intermediate formation and thus the overall CO_(2)RR kinetic was improved,and also restrained the competitive hydrogen evolution reaction.Due to the attributes of Ni-Co atomic pairs configuration,the developed NiN_(3)?CoN_(3)-NC with superior catalytic activity,selectivity,and durability,with a high turnover frequency of 2265 h^(-1)at-1.1 V(vs.RHE)and maximum Faradaic efficiency of 97.7%for CO production.This work demonstrates the great potential of DACs as highly efficient catalysts for CO_(2)RR,provides a useful strategy to design heteronuclear DACs,exploits the synergistic effect of multiple metal sites to facilitate complex CO_(2)RR catalytic reactions,and inspires more efforts to develop the potential of DACs in various fields.
基金This work was financially supported by the National Natural Science Foundation of China(grant nos.21802146 and 21722308)the CAS Key Research Project of Frontier Science(CAS grant no.QYZDB-SSW-SLH024)the Frontier Cross Project of national laboratory for molecular sciences(grant no.051Z011BZ3).
文摘The activation and reduction of N_(2)to produce ammonia under mild conditions is of great interest,but challenges remain.Here,we report a breakthrough in efficient dinitrogen cleavage by employing small Ptn+(n=1–4)clusters and convenient plasma assistance.The reactivity of Pt3+is found to be substantially higher than that of other clusters,and the formed Pt3N7+shows prominent mass abundance among the odd-nitrogen products.We illustrate that a chain reaction path within dual cluster cooperation,especially via a“3+2”mode,is beneficial to N≡N triple bond dissociation,embodying efficient synergistic catalysis.A key intermediate containing a bridged N_(2)of binding with two Pt clusters facilitates N_(2)activation with significantly enhanced interactions between the d orbitals of Pt and the antibondingπ*-orbitals of N_(2).Furthermore,by reacting the Pt_(n)N_(m)+clusters with H_(2),we observed hydrogenation products of both evenand odd-hydrogen species,indicative of ammonia release.The in situ synthesized platinum nitride clusters,typically Pt_(3)N_(7)+,induce a highly active N site for hydrogen anchoring,enabling a cost-effective hydrotreating process for ammonia synthesis.
基金supported by the National Natural Science Foundation of China(21633008)the Strategic Priority Research Program of CAS(XDA09030104)+1 种基金Jilin Province Science and Technology Development Program(20160622037JC)the Hundred Talents Program of Chinese Academy of Science。
文摘Water electrolysis is regarded as an environmental friendly and effective technique for large-scale hydrogen(H2)production[1,2].To date,Pt-based electrocatalysts are still the most efficient HER catalysts[3].However,the prohibitive cost and scarcity of precious metal catalysts have restricted its large-scale applications.Thus,finding an earth-abundant and effective alternative electrocatalysts is crucial to the development of‘hydrogen economy'.
基金supported by the National Natural Science Foundation of China(22125802 and 22108012)Natural Science Foundation of Beijing Municipality(2222017)Fundamental Research Funds for the Central Universities(BUCTRC-202109)。
文摘The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological environment.In this work,ciprofloxacin(CIP)was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater.The sodium alginate(SA)gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe^(3+)and Mn^(2+)as cross-linking agents.Preparation conditions such as metal ions concentration,mass fraction of SA,polymerization temperature and dual-metal ions as crosslinking agent were optimized.Moreover,the effects of operating conditions such as initial concentration of CIP,pH value and catalyst dosage on CIP removal were studied.The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics,and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics.The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles.The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.
