Oxygen evolution reaction(OER)is pivotal to drive green hydrogen generation from water electrolysis,but yet is strictly overshadowed by the sluggish reaction kinetics.Earth-abundant and cut-price transitionmetal compo...Oxygen evolution reaction(OER)is pivotal to drive green hydrogen generation from water electrolysis,but yet is strictly overshadowed by the sluggish reaction kinetics.Earth-abundant and cut-price transitionmetal compounds,particularly Co Fe layered-double-hydroxides(LDHs),show the distinct superiorities in contrast to noble metals and their derivatives.In this review,we firstly underline their fundamental issues in electrocatalytic water oxidation,including Co Fe LDHs crystal structure,the surface of(hydr)oxides confined to OER and the controversial roles of Fe species,aiming at understanding the structure-related activity and catalytic mechanism.Advanced approaches for optimizing OER activity of Co Fe LDHs are then comprehensively overviewed,which will shed light on the different working mechanisms and provide a concise analysis of their unique advantages.Finally,a perspective on the future development of Co Fe LDHs electrocatalysts is offered.We hope this review can give a concise and explicit guidance for the development of transition-metal-based electrocatalysts in the energy field.展开更多
Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electro...Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electron gas （2DEG） at oxide interfaces. Due to the presence of oxygen vacancies at the SrTiO3 surface, metallic conduction can be created at room temperature in perovskite-type interfaces when the overlayer oxide ABO3 has Al, Ti, Zr, or Hf elements at the B sites. Furthermore, relying on interface-stabilized oxygen vacancies, we have created a new type of 2DEG at the heterointerface between SrTiO3 and a spinel γ-Al2O3 epitaxial film with compatible oxygen ion sublattices. This 2DEG exhibits an electron mobility exceeding 100000 cm2·V-1·s-1, more than one order of magnitude higher than those of hitherto investigated perovskite-type interfaces. Our findings pave the way for the design of high-mobility all-oxide electronic devices and open a route toward the studies of mesoscopic physics with complex oxides.展开更多
According to first principle simulations, we theoretically predict a type of stable single-layer graphene oxide（C_2O）.Using density functional theory（DFT）, C_2O is found to be a direct gap semiconductor. In additi...According to first principle simulations, we theoretically predict a type of stable single-layer graphene oxide（C_2O）.Using density functional theory（DFT）, C_2O is found to be a direct gap semiconductor. In addition, we obtain the absorption spectra of the periodic structure of C_2O, which show optical anisotropy. To study the optical properties of C_2O nanostructures, time-dependent density functional theory（TDDFT） is used. The C_2O nanostructure has a strong absorption near 7 eV when the incident light polarizes along the armchair-edge. Besides, we find that the optical properties can be controlled by the edge configuration and the size of the C_2O nanostructure. With the elongation strain increasing, the range of light absorption becomes wider and there is a red shift of absorption spectrum.展开更多
Atmospheric pollutants can deteriorate air quality and put human health at risk.There is a growing need for green,economical,and efficient technologies,among which catalytic elimination technology is the most promisin...Atmospheric pollutants can deteriorate air quality and put human health at risk.There is a growing need for green,economical,and efficient technologies,among which catalytic elimination technology is the most promising,to remove atmospheric pollutants.Two-dimensional transition metal oxides(2D TMOs)have recently become attractive catalysts due to their highly exposed active sites,excellent reactant transport properties,and extraordinary catalytic performance.This review systematically summarizes the topdown and bottom-up preparation methods of 2D TMOs and focuses on the specific applications of 2D TMOs in the catalytic elimination of atmospheric inorganic pollutants and volatile organic pollutants.The development of 2D TMOs in the catalytic elimination of atmospheric pollutants is prospected.This review is expected to provide design insights into efficient 2D TMOs to remove atmospheric pollutants.展开更多
The atomically thin nature of two-dimensional(2D)layered materials makes them susceptible to charge trapping by randomly created disorders,adversely affecting carrier dynamics such as charge transport and exciton life...The atomically thin nature of two-dimensional(2D)layered materials makes them susceptible to charge trapping by randomly created disorders,adversely affecting carrier dynamics such as charge transport and exciton lifetime.Typically,these disorders lead to poor device performance or require additional space to mitigate performance degradation.In this study,we investigate 2D layered Dion–Jacobson(DJ)-phase oxide perovskite nanosheets,which exhibit charge trapping within their well-defined quantum well(QW)structures,resulting in unique tailoring of electrical conductivity and photoconductivity.These DJ-phase perovskites,composed of tunable atomic constituents,demonstrate resonant tunneling and anomalous charge trapping due to their ultra-clean QWs.Remarkably,the conductivity of insulating HSr_(2)Nb_(3)O_(10)(HSNO)increased over 1000 times upon applying voltage without additional treatments.We observed persistent photoconductivity in 2D vertical heterostructure devices,attributed to charge trapping in QWs,and demonstrated artificial synaptic behaviours in a single flake with tailored energy consumption.Varying the number of perovskite layers significantly allows the tunability of the energy bandgap.This study also highlights the high tunability of 2D perovskite nanosheets,promising various applications,including magnetic,high-k dielectric,and resistive switching devices.Our findings suggest a new class of ionic layered materials with great potential as novel two-dimensional building blocks for device applications.展开更多
The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhi...Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.展开更多
Since the discovery of graphene,two-dimensional(2D)semiconductors have been attracted intensive interest due to their unique properties.They have exhibited potential applications in next generation electronic and opto...Since the discovery of graphene,two-dimensional(2D)semiconductors have been attracted intensive interest due to their unique properties.They have exhibited potential applications in next generation electronic and optoelectronic devices.However,most of the 2D semiconductor are known to suffer from the ambient oxidation which degrade the materials and therefore hinder us from the intrinsic materials’properties and the optimized performance of devices.In this review,we summarize the recent progress on both fundamentals and applications of the oxidations of 2D semiconductors.We begin with the oxidation mechanisms in black phosphorus,transition metal dichalcogenides and transition metal monochalcogenides considering the factors such as oxygen,water,and light.Then we show the commonly employed passivation techniques.In the end,the emerging applications utilizing controlled oxidations will be introduced.展开更多
DNA/GO composite plays a significant role in the research field of biotechnology and nanotechnology,and attracts a great deal of interest.However,it is still unclear how the oxidation degree of the graphene-based surf...DNA/GO composite plays a significant role in the research field of biotechnology and nanotechnology,and attracts a great deal of interest.However,it is still unclear how the oxidation degree of the graphene-based surface affects the adsorption process of single-strand DNA(ssDNA).In this paper,based on the molecular dynamics simulations,we find that ssDNA molecule is absorbed on the GO surface in the most stable state with the oxidation degree around 15%.The microscopic mechanism is attributed to the van Der Walls and the electrostatic interactions between the ssDNA molecule and the graphene-based surface,which is accompanied with theπ-πstacking and hydrogen bond formation.The number ofπ-πstacking between ssDNA and GO reaches the maximum value when the oxidation degree is around 15%among all the GO surfaces.Our simulation results also reveal the coexistence of stretched and curved configurations as well as the adsorption orientation of ssDNA on the GO surface.Furthermore,it is found that the absorbed ssDNA molecules are more likely to move on the graphene-based surface of low oxidation degree,especially on pristine graphene.Our work provides the physics picture of ssDNA’s physisorption dynamics onto graphene-based surface and it is helpful in designing DNA/GO nanomaterials.展开更多
Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen mor...Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen energy.Two-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with certainty.This paper reviews the application of 2D materials in UOR in alkaline electrolytes.And a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different elements.In addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and prospected.It is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.展开更多
The emerging two-dimensional(2D)membranes offer a promising way to improve the water desalination performance of traditional membranes.MXene/graphene oxide(GO) composite membrane are known for their high separation pe...The emerging two-dimensional(2D)membranes offer a promising way to improve the water desalination performance of traditional membranes.MXene/graphene oxide(GO) composite membrane are known for their high separation performance and structural stability.In this study,molecular simulations are performed to investigate the desalination performance of the 2D MXene/GO membrane.The results reveal that the surface of the MXene nanosheet could induce the formation of ordered water structures,thereby accelerating the water transport in the 2D membrane.The higher rejection rate would be found in MXene/GO membrane with a larger GO oxidation degree owing to the sterichindrance effect induced by the functional groups on the GO surface.Overall,the MXene/GO(20) membrane with the interlayer spacing of 0.9 nm shows the highest water permeability(37.22×10^(-7)L·m^(-1)·h^(-1)·bar^(-1),1 bar=0.1 MPa)and a salt rejection of 100%.The results could provide theoretical insights for developing 2D membranes for water desalination.展开更多
Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and stor...Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and storage,value-added chemical synthesis and environmental remediation.However,their environmental appli-cations lack of a comprehensive summary and in-depth discussion.In this review,recent progresses in synthesis routes and advanced characterization techniques for 2D SACs are introduced,and a comprehensive discussion on their applications in environmental remediation is presented.Generally,2D SACs can be effective in catalytic elimination of aqueous and gaseous pollutants via radical or non-radical routes and transformation of toxic pollutants into less poisonous species or highly value-added products,opening a new horizon for the contami-nant treatment.In addition,in-depth reaction mechanisms and potential pathways are systematically discussed,and the relationship between the structure-performance is highlighted.Finally,several critical challenges within this field are presented,and possible directions for further explorations of 2D SACs in environmental remediation are suggested.Although the research of 2D SACs in the environmental application is still in its infancy,this review will provide a timely summary on the emerging field,and would stimulate tremendous interest for designing more attractive 2D SACs and promoting their wide applications.展开更多
Three-dimensional(3D)functional graphenebased architecture with superior electrical conductivity and good mechanical strength has promising applications in energy storage and electrics.Viscoelasticity-adjustable inks ...Three-dimensional(3D)functional graphenebased architecture with superior electrical conductivity and good mechanical strength has promising applications in energy storage and electrics.Viscoelasticity-adjustable inks make it possible to achieve desired 3D architectures with interconnected and continuous interior networks by microextrusion printing.In this work,ultra-low-concentration graphene oxide(GO)inks of~15 mg·ml-1 have been obtained and demonstrated in direct 3D printing with a facile cross-linking(direct ink writing).The rheological behavior of the GO strategy by cations,which is the lowest concentration to achieve direct ink writing inks,could be adjusted from 1×10^(4) to 1×10^(5) Pa·s^(-1) with different concentrations of cations due to strong cross-linking networks between GO sheets and cations.Meanwhile,the specific strength and electrical conductivity of 3D-printed graphene architecture are notably enhanced,reaching up to 51.7×10^(3) N·m·kg^(-1)and 119 S·m^(-1),which are superior to conventional graphene aerogels.Furthermore,3D printing graphene-based architecture assembled in micro-superc apacitor exhibits excellent electrochemical performance,which can be ascribed to the effective ion transportation through the interconnected networks.The strategy demonstrated is useful in the design of complex-shaped,graphene-based architectures for scalable manufacturing of practical energy storage applications.展开更多
Zinc manganese oxide(ZMO)system represents a notable family of mixed transition metal oxides(MTMOs)because of their superiority of the high theoretical capacity,adequacy of natural content,and low cost.However,the met...Zinc manganese oxide(ZMO)system represents a notable family of mixed transition metal oxides(MTMOs)because of their superiority of the high theoretical capacity,adequacy of natural content,and low cost.However,the methods to match both the reliable synthesis and the designable construction of large-sized two-dimensional(2D)ZMO nanosheets are still considered as grand challenges.Herein,we have successfully realized the preparation of 2D ZMO nanosheets with large lateral sizes up to~20 mm by simple pyrolysis of 2D metal–organic framework(MOF)nanosheets precursor.The growth mechanism of 2D MOF is proposed to be based on the lamellar micelles formed by polyvinyl pyrrolidone(PVP).The obtained 2D and porous ZMO nanosheets exhibit high specific capacity as well as good rate capability.More importantly,the as-prepared ZMO electrode shows a remarkable capacity increment upon cycling(from 832 mAh g^(-1) at the 2nd cycle to 1418 mAh g^(-1) at the 700th cycle,at 1 A g^(-1)).Through simple adjustment of the calcination temperature,the valence state of Mn species in the yielding ZMO samples can be fine-tuned.Through systematic investigation towards these ZMOs containing different Mn species,the extra specific capacity is revealed to be chiefly on account of the arising of the valence state of Mn upon the cycling process.Moreover,it is disclosed that the higher-valent Mn the pristine ZMO contains,the more additional capacity it gains upon cycling.We believe that this work will inspire more detailed analysis on the relationship between the valence state of Mn and extra capacity.展开更多
This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojun...This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojunction band diagram of InZnO bilayer was modified by the cation composition to form the two-dimensional electron gas(2DEG)at the interface quantum well,as verified using a metal−insulator−semiconductor(MIS)device.Although the 2DEG indeed contributes to a higher mobility than the monolayer channel,the competition and cooperation between the gate field and the built-in field strongly affect such mobility-boosting effect,originating from the carrier inelastic collision at the heterojunction interface and the gate field-induced suppression of quantum well.Benefited from the proper energy-band engineering,a high mobility of 84.3 cm2·V^(−1)·s^(−1),a decent threshold voltage(V_(th))of−6.5 V,and a steep subthreshold swing(SS)of 0.29 V/dec were obtained in InZnO-based heterojunction TFT.展开更多
This paper finds that the two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was inv...This paper finds that the two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was investigated in depth using Hall effect measurements,high resolution x-ray diffraction,scanning electron microscopy,x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy.The results reveal that the formation of surface oxide is the main reason for the degradation,and the surface oxidation always occurs within the surface hexagonal defects for high Al-content AlGaN/GaN heterostructures.展开更多
A systematic study of the two-dimensional electron gas at La AlO_3/SrTiO_3（110） interface reveals an anisotropy along two specific directions, [001] and 1ī0. The anisotropy becomes distinct for the interface prepar...A systematic study of the two-dimensional electron gas at La AlO_3/SrTiO_3（110） interface reveals an anisotropy along two specific directions, [001] and 1ī0. The anisotropy becomes distinct for the interface prepared under high oxygen pressure with low carrier density. Angular dependence of magnetoresistance shows that the electron confinement is stronger along the 1ī0 direction. Gate-tunable magnetoresistance reveals a clear in-plane anisotropy of the spin–orbit coupling,and the spin relaxation mechanism along both directions belongs to D＇yakonov–Perel＇（DP） scenario. Moreover, in-plane anisotropic superconductivity is observed for the sample with high carrier density, the superconducting transition temperature is lower but the upper critical field is higher along the 1ī0 direction. This in-plane anisotropy could be ascribed to the anisotropic band structure along the two crystallographic directions.展开更多
The structural modulation of metal-based heterostructure plays a vital role in achieving enhanced performances for highly efficient electrocatalysis.Here we design submonolayered Ru-modified Pd mesoporous nanosheets(P...The structural modulation of metal-based heterostructure plays a vital role in achieving enhanced performances for highly efficient electrocatalysis.Here we design submonolayered Ru-modified Pd mesoporous nanosheets(Pd-Ru MNSs)with the exposure of both Pd and Ru active sites as well as the high atomic utilization of two-dimensional structure.The obtained Pd-Ru MNSs can act as a highly efficient multifunctional catalyst for hydrogen evolution reaction(HER)and alcohol oxidation reactions including ethylene glycol oxidation(EGOR)and ethanol oxidation(EOR),offering new opportunities towards the alcohol oxidation assisted hydrogen production.Specifically,Pd-Ru MNSs demonstrate excellent HER performance in alkaline electrolyte,requiring an overpotential of only 16mV to reach 10mAcm^(−2),significantly outperforming Pd mesoporous nanosheets and commercial catalysts.Density functional theory calculations reveal that the Ru sites in Pd-Ru MNSs could facilitate the water adsorption,accelerate the water dissociation,and optimize the hydrogen desorption,leading to the superior HER activity.Pd-Ru MNSs also exhibit high mass activities of 11.19 A mg^(−1)Pd for EGOR and 8.84 A mg^(−1)Pd for EOR,which is 7.8 and 9.6 times than that of commercial Pd/C,respectively.The EGOR reaction pathway over Pd-Ru MNSs was further investigated by using in situ Fourier-transform infrared spectroscopy.展开更多
Two-dimensional(2D)metal oxides and chalcogenides(MOs&MCs)have been regarded as a new class of promising electro-and photocatalysts for many important chemical reactions such as hydrogen evolution reaction,CO_(2) ...Two-dimensional(2D)metal oxides and chalcogenides(MOs&MCs)have been regarded as a new class of promising electro-and photocatalysts for many important chemical reactions such as hydrogen evolution reaction,CO_(2) reduction reaction and N2 reduction reaction in virtue of their outstanding physicochemical properties.However,pristine 2D MOs&MCs generally show the relatively poor catalytic performances due to the low electrical conductivity,few active sites and fast charge recombination.Therefore,considerable efforts have been devoted to engineering 2D MOs&MCs by rational structural design and chemical modification to further improve the catalytic activities.Herein,we comprehensively review the recent advances for engineering technologies of 2D MOs&MCs,which are mainly focused on the intercalation,doping,defects creation,facet design and compositing with functional materials.Meanwhile,the relationship between morphological,physicochemical,electronic,and optical properties of 2D MOs&MCs and their electro-and photocatalytic performances is also systematically discussed.Finally,we further give the prospect and challenge of the field and possible future research directions,aiming to inspire more research for achieving high-performance 2D MOs&MCs catalysts in energy storage and conversion fields.展开更多
Two-dimensional(2D)heterostructures based on the combination of transition metal dichalcogenides(TMDs)and transition metal oxides(TMOs)have aroused growing attention due to their integrated merits of both components a...Two-dimensional(2D)heterostructures based on the combination of transition metal dichalcogenides(TMDs)and transition metal oxides(TMOs)have aroused growing attention due to their integrated merits of both components and multiple functionalities.However,nondestructive approaches of constructing TMD-TMO heterostructures are still very limited.Here,we develop a novel type of lateral TMD-TMO heterostructure(NbS2-Nb2O5-NbS2)using a simple lithography-free,direct laser-patterning technique.The perfect contact of an ultrathin TMO channel(Nb2O5)with two metallic TMDs(NbS2)electrodes guarantee strong electrical signals in a two-terminal sensor.Distinct from sensing mechanisms in separate TMOs or TMDs,this sensor works based on the modulation of surface conduction of the ultrathin TMO(Nb2O5)channel through an adsorbed layer of water molecules.The sensor thus exhibits high selectivity and ultrahigh sensitivity for room-temperature detection of NH3(ΔR/R=80%at 50 ppm),superior to the reported NH3 sensors based on 2D materials,and a positive temperature coefficient of resistance as high as 15%–20%/℃.Bending-invariant performance and high reliability are also demonstrated in flexible versions of sensors.Our work provides a new strategy of lithography-free processing of novel TMD-TMO heterostructures towards high-performance sensors,showing great potential in the applications of future portable and wearable electronics.展开更多
基金National Natural Science Foundation of China(Nos.21773093 and 22175077)Natural Science Foundation of Guangdong Province(Nos.2021A1515012351 and 2017B030306004)Guangdong Special Support Program(No.2017TQ04N224)。
文摘Oxygen evolution reaction(OER)is pivotal to drive green hydrogen generation from water electrolysis,but yet is strictly overshadowed by the sluggish reaction kinetics.Earth-abundant and cut-price transitionmetal compounds,particularly Co Fe layered-double-hydroxides(LDHs),show the distinct superiorities in contrast to noble metals and their derivatives.In this review,we firstly underline their fundamental issues in electrocatalytic water oxidation,including Co Fe LDHs crystal structure,the surface of(hydr)oxides confined to OER and the controversial roles of Fe species,aiming at understanding the structure-related activity and catalytic mechanism.Advanced approaches for optimizing OER activity of Co Fe LDHs are then comprehensively overviewed,which will shed light on the different working mechanisms and provide a concise analysis of their unique advantages.Finally,a perspective on the future development of Co Fe LDHs electrocatalysts is offered.We hope this review can give a concise and explicit guidance for the development of transition-metal-based electrocatalysts in the energy field.
文摘Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electron gas （2DEG） at oxide interfaces. Due to the presence of oxygen vacancies at the SrTiO3 surface, metallic conduction can be created at room temperature in perovskite-type interfaces when the overlayer oxide ABO3 has Al, Ti, Zr, or Hf elements at the B sites. Furthermore, relying on interface-stabilized oxygen vacancies, we have created a new type of 2DEG at the heterointerface between SrTiO3 and a spinel γ-Al2O3 epitaxial film with compatible oxygen ion sublattices. This 2DEG exhibits an electron mobility exceeding 100000 cm2·V-1·s-1, more than one order of magnitude higher than those of hitherto investigated perovskite-type interfaces. Our findings pave the way for the design of high-mobility all-oxide electronic devices and open a route toward the studies of mesoscopic physics with complex oxides.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0303600)the National Natural Science Foundation of China(Grant Nos.11474207 and 11374217)
文摘According to first principle simulations, we theoretically predict a type of stable single-layer graphene oxide（C_2O）.Using density functional theory（DFT）, C_2O is found to be a direct gap semiconductor. In addition, we obtain the absorption spectra of the periodic structure of C_2O, which show optical anisotropy. To study the optical properties of C_2O nanostructures, time-dependent density functional theory（TDDFT） is used. The C_2O nanostructure has a strong absorption near 7 eV when the incident light polarizes along the armchair-edge. Besides, we find that the optical properties can be controlled by the edge configuration and the size of the C_2O nanostructure. With the elongation strain increasing, the range of light absorption becomes wider and there is a red shift of absorption spectrum.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences,China(Nos.XDA23010300 and XDA23010000)National Natural Science Foundation of China(Nos.51878644 and 41573138)+1 种基金the National Key Research and Development Program of China(No.2016YFA0203000)the Plan for"National Youth Talents"of the Organization Department of the Central Committee。
文摘Atmospheric pollutants can deteriorate air quality and put human health at risk.There is a growing need for green,economical,and efficient technologies,among which catalytic elimination technology is the most promising,to remove atmospheric pollutants.Two-dimensional transition metal oxides(2D TMOs)have recently become attractive catalysts due to their highly exposed active sites,excellent reactant transport properties,and extraordinary catalytic performance.This review systematically summarizes the topdown and bottom-up preparation methods of 2D TMOs and focuses on the specific applications of 2D TMOs in the catalytic elimination of atmospheric inorganic pollutants and volatile organic pollutants.The development of 2D TMOs in the catalytic elimination of atmospheric pollutants is prospected.This review is expected to provide design insights into efficient 2D TMOs to remove atmospheric pollutants.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the government of the Republic of Korea(the Ministry of Science and ICT)(Nos.NRF-2023R1A2C2003247,2021R1C1C2091728,and 2021R1A2C2010695)the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(No.RS-2024-00402972)the National Research Council of Science&Technology(NST)grant by the Korea。
文摘The atomically thin nature of two-dimensional(2D)layered materials makes them susceptible to charge trapping by randomly created disorders,adversely affecting carrier dynamics such as charge transport and exciton lifetime.Typically,these disorders lead to poor device performance or require additional space to mitigate performance degradation.In this study,we investigate 2D layered Dion–Jacobson(DJ)-phase oxide perovskite nanosheets,which exhibit charge trapping within their well-defined quantum well(QW)structures,resulting in unique tailoring of electrical conductivity and photoconductivity.These DJ-phase perovskites,composed of tunable atomic constituents,demonstrate resonant tunneling and anomalous charge trapping due to their ultra-clean QWs.Remarkably,the conductivity of insulating HSr_(2)Nb_(3)O_(10)(HSNO)increased over 1000 times upon applying voltage without additional treatments.We observed persistent photoconductivity in 2D vertical heterostructure devices,attributed to charge trapping in QWs,and demonstrated artificial synaptic behaviours in a single flake with tailored energy consumption.Varying the number of perovskite layers significantly allows the tunability of the energy bandgap.This study also highlights the high tunability of 2D perovskite nanosheets,promising various applications,including magnetic,high-k dielectric,and resistive switching devices.Our findings suggest a new class of ionic layered materials with great potential as novel two-dimensional building blocks for device applications.
文摘The labels of VU1 and VU2 in Fig.1(b)of the paper[Chin.Phys.B 34046801(2025)]were not correctly placed.The correct figure is provided.This modification does not affect the result presented in the paper.
基金financial support from the National Key Research&Development Program of China(Grant No.2023YFA1406500)the National Natural Science Foundation of China(Grant Nos.12104504,52461160327 and 92477205)the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China[Grant Nos.22XNKJ30(W.J.)and 24XNKJ17(C.W.)]。
文摘Kagome materials are known for hosting exotic quantum states,including quantum spin liquids,charge density waves,and unconventional superconductivity.The search for kagome monolayers is driven by their ability to exhibit neat and well-defined kagome bands near the Fermi level,which are more easily realized in the absence of interlayer interactions.However,this absence also destabilizes the monolayer forms of many bulk kagome materials,posing significant challenges to their discovery.In this work,we propose a strategy to address this challenge by utilizing oxygen vacancies in transition metal oxides within a“1+3”design framework.Through high-throughput computational screening of 349 candidate materials,we identified 12 thermodynamically stable kagome monolayers with diverse electronic and magnetic properties.These materials were classified into three categories based on their lattice geometry,symmetry,band gaps,and magnetic configurations.Detailed analysis of three representative monolayers revealed kagome band features near their Fermi levels,with orbital contributions varying between oxygen 2p and transition metal d states.This study demonstrates the feasibility of the“1+3”strategy,offering a promising approach to uncovering low-dimensional kagome materials and advancing the exploration of their quantum phenomena.
基金partially supported by the National Natural Science Foundation of China(No.11804397)the Hunan High-Level Talent Program(No.2019RS1006)。
文摘Since the discovery of graphene,two-dimensional(2D)semiconductors have been attracted intensive interest due to their unique properties.They have exhibited potential applications in next generation electronic and optoelectronic devices.However,most of the 2D semiconductor are known to suffer from the ambient oxidation which degrade the materials and therefore hinder us from the intrinsic materials’properties and the optimized performance of devices.In this review,we summarize the recent progress on both fundamentals and applications of the oxidations of 2D semiconductors.We begin with the oxidation mechanisms in black phosphorus,transition metal dichalcogenides and transition metal monochalcogenides considering the factors such as oxygen,water,and light.Then we show the commonly employed passivation techniques.In the end,the emerging applications utilizing controlled oxidations will be introduced.
基金supported by the National Natural Science Foundation of China(Grant Nos.11305237 and 11974366)the Fundamental Research Funds for the Central Universities,China,the Natural Science Foundation of Shanghai,China(Grant No.19ZR1463200)the Key Research Program of Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SLH053).
文摘DNA/GO composite plays a significant role in the research field of biotechnology and nanotechnology,and attracts a great deal of interest.However,it is still unclear how the oxidation degree of the graphene-based surface affects the adsorption process of single-strand DNA(ssDNA).In this paper,based on the molecular dynamics simulations,we find that ssDNA molecule is absorbed on the GO surface in the most stable state with the oxidation degree around 15%.The microscopic mechanism is attributed to the van Der Walls and the electrostatic interactions between the ssDNA molecule and the graphene-based surface,which is accompanied with theπ-πstacking and hydrogen bond formation.The number ofπ-πstacking between ssDNA and GO reaches the maximum value when the oxidation degree is around 15%among all the GO surfaces.Our simulation results also reveal the coexistence of stretched and curved configurations as well as the adsorption orientation of ssDNA on the GO surface.Furthermore,it is found that the absorbed ssDNA molecules are more likely to move on the graphene-based surface of low oxidation degree,especially on pristine graphene.Our work provides the physics picture of ssDNA’s physisorption dynamics onto graphene-based surface and it is helpful in designing DNA/GO nanomaterials.
基金financially supported by the National Key Research and Development Program of China(No.2020YFB1713500)the Major Science and Technology Projects of Henan Province(No.221100230200)+3 种基金Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.23IRTSTHN009)the Project of Science and Technology Department of Henan Province(Nos.232102241034 and 222102240074)the Natural Science Foundation of Suzhou University of Science and Technology(No.XKQ2020002)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.22KJB530009)。
文摘Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen energy.Two-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with certainty.This paper reviews the application of 2D materials in UOR in alkaline electrolytes.And a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different elements.In addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and prospected.It is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.
基金supported by the National Natural Science Foundation of China(22078251,21706197)the Open Project of Hubei Key Laboratory of Novel Reactor and Green Chemical Technology(NRG202407)+1 种基金the Ministry-of-Education,Key Laboratory for the Synthesis and Application of Organic Functional Molecules(KLSAOFM2511)the Graduate Innovative Fund of Wuhan Institute of Technology(CX2023024)。
文摘The emerging two-dimensional(2D)membranes offer a promising way to improve the water desalination performance of traditional membranes.MXene/graphene oxide(GO) composite membrane are known for their high separation performance and structural stability.In this study,molecular simulations are performed to investigate the desalination performance of the 2D MXene/GO membrane.The results reveal that the surface of the MXene nanosheet could induce the formation of ordered water structures,thereby accelerating the water transport in the 2D membrane.The higher rejection rate would be found in MXene/GO membrane with a larger GO oxidation degree owing to the sterichindrance effect induced by the functional groups on the GO surface.Overall,the MXene/GO(20) membrane with the interlayer spacing of 0.9 nm shows the highest water permeability(37.22×10^(-7)L·m^(-1)·h^(-1)·bar^(-1),1 bar=0.1 MPa)and a salt rejection of 100%.The results could provide theoretical insights for developing 2D membranes for water desalination.
基金This work was financially supported by the National Natural Science Foundation of China(51602133,51876093)China MOST(2018YFE0183600).
文摘Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and storage,value-added chemical synthesis and environmental remediation.However,their environmental appli-cations lack of a comprehensive summary and in-depth discussion.In this review,recent progresses in synthesis routes and advanced characterization techniques for 2D SACs are introduced,and a comprehensive discussion on their applications in environmental remediation is presented.Generally,2D SACs can be effective in catalytic elimination of aqueous and gaseous pollutants via radical or non-radical routes and transformation of toxic pollutants into less poisonous species or highly value-added products,opening a new horizon for the contami-nant treatment.In addition,in-depth reaction mechanisms and potential pathways are systematically discussed,and the relationship between the structure-performance is highlighted.Finally,several critical challenges within this field are presented,and possible directions for further explorations of 2D SACs in environmental remediation are suggested.Although the research of 2D SACs in the environmental application is still in its infancy,this review will provide a timely summary on the emerging field,and would stimulate tremendous interest for designing more attractive 2D SACs and promoting their wide applications.
基金financially supported by the National Natural Science Foundation of China(No.51802195)Chen Guang Scholar Project of Shanghai Education Commission(No.19CG53)。
文摘Three-dimensional(3D)functional graphenebased architecture with superior electrical conductivity and good mechanical strength has promising applications in energy storage and electrics.Viscoelasticity-adjustable inks make it possible to achieve desired 3D architectures with interconnected and continuous interior networks by microextrusion printing.In this work,ultra-low-concentration graphene oxide(GO)inks of~15 mg·ml-1 have been obtained and demonstrated in direct 3D printing with a facile cross-linking(direct ink writing).The rheological behavior of the GO strategy by cations,which is the lowest concentration to achieve direct ink writing inks,could be adjusted from 1×10^(4) to 1×10^(5) Pa·s^(-1) with different concentrations of cations due to strong cross-linking networks between GO sheets and cations.Meanwhile,the specific strength and electrical conductivity of 3D-printed graphene architecture are notably enhanced,reaching up to 51.7×10^(3) N·m·kg^(-1)and 119 S·m^(-1),which are superior to conventional graphene aerogels.Furthermore,3D printing graphene-based architecture assembled in micro-superc apacitor exhibits excellent electrochemical performance,which can be ascribed to the effective ion transportation through the interconnected networks.The strategy demonstrated is useful in the design of complex-shaped,graphene-based architectures for scalable manufacturing of practical energy storage applications.
基金This project is financially supported by National Natural Science Foundation of China(Grant No.51502060)Natural Science Foundation of Shandong Province,China(Grant No.ZR2015EQ010 and No.ZR2019MB027)the Fundamental Research Funds for the Central Universities(Grant No.2015DXGJMS004).
文摘Zinc manganese oxide(ZMO)system represents a notable family of mixed transition metal oxides(MTMOs)because of their superiority of the high theoretical capacity,adequacy of natural content,and low cost.However,the methods to match both the reliable synthesis and the designable construction of large-sized two-dimensional(2D)ZMO nanosheets are still considered as grand challenges.Herein,we have successfully realized the preparation of 2D ZMO nanosheets with large lateral sizes up to~20 mm by simple pyrolysis of 2D metal–organic framework(MOF)nanosheets precursor.The growth mechanism of 2D MOF is proposed to be based on the lamellar micelles formed by polyvinyl pyrrolidone(PVP).The obtained 2D and porous ZMO nanosheets exhibit high specific capacity as well as good rate capability.More importantly,the as-prepared ZMO electrode shows a remarkable capacity increment upon cycling(from 832 mAh g^(-1) at the 2nd cycle to 1418 mAh g^(-1) at the 700th cycle,at 1 A g^(-1)).Through simple adjustment of the calcination temperature,the valence state of Mn species in the yielding ZMO samples can be fine-tuned.Through systematic investigation towards these ZMOs containing different Mn species,the extra specific capacity is revealed to be chiefly on account of the arising of the valence state of Mn upon the cycling process.Moreover,it is disclosed that the higher-valent Mn the pristine ZMO contains,the more additional capacity it gains upon cycling.We believe that this work will inspire more detailed analysis on the relationship between the valence state of Mn and extra capacity.
基金supported by National Key Research and Development Program(2021YFB3600802)Shenzhen Municipal Scientific Program(JSGG20220831103803007,SGDX20211123145404006)Guangdong Basic and Applied Basic Research Foundation(2022A1515110029)
文摘This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojunction band diagram of InZnO bilayer was modified by the cation composition to form the two-dimensional electron gas(2DEG)at the interface quantum well,as verified using a metal−insulator−semiconductor(MIS)device.Although the 2DEG indeed contributes to a higher mobility than the monolayer channel,the competition and cooperation between the gate field and the built-in field strongly affect such mobility-boosting effect,originating from the carrier inelastic collision at the heterojunction interface and the gate field-induced suppression of quantum well.Benefited from the proper energy-band engineering,a high mobility of 84.3 cm2·V^(−1)·s^(−1),a decent threshold voltage(V_(th))of−6.5 V,and a steep subthreshold swing(SS)of 0.29 V/dec were obtained in InZnO-based heterojunction TFT.
基金Project supported by the Major Program and State Key Program of National Natural Science of China (Grant Nos 60890191 and 60736033)the National Key Science & Technology Special Project (Grant No 2008ZX 01002)
文摘This paper finds that the two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was investigated in depth using Hall effect measurements,high resolution x-ray diffraction,scanning electron microscopy,x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy.The results reveal that the formation of surface oxide is the main reason for the degradation,and the surface oxidation always occurs within the surface hexagonal defects for high Al-content AlGaN/GaN heterostructures.
基金Project supported by the Ministry of Science and Technology of China(Grant Nos.2013CB921701,2013CBA01603,and 2014CB920903)the National Natural Science Foundation of China(Grant Nos.10974019,51172029,91121012,11422430,11374035,11474022,and 11474024)+1 种基金the Program for New Century Excellent Talents in the University of the Ministry of Education of China(Grant No.NCET-13-0054)the Beijing Higher Education Young Elite Teacher Project,China(Grant No.YETP0238)
文摘A systematic study of the two-dimensional electron gas at La AlO_3/SrTiO_3（110） interface reveals an anisotropy along two specific directions, [001] and 1ī0. The anisotropy becomes distinct for the interface prepared under high oxygen pressure with low carrier density. Angular dependence of magnetoresistance shows that the electron confinement is stronger along the 1ī0 direction. Gate-tunable magnetoresistance reveals a clear in-plane anisotropy of the spin–orbit coupling,and the spin relaxation mechanism along both directions belongs to D＇yakonov–Perel＇（DP） scenario. Moreover, in-plane anisotropic superconductivity is observed for the sample with high carrier density, the superconducting transition temperature is lower but the upper critical field is higher along the 1ī0 direction. This in-plane anisotropy could be ascribed to the anisotropic band structure along the two crystallographic directions.
基金financial support from the National Natural Science Foundation of China(No.52471219)the Fundamental Research Funds for the Central Universities(No.00007838)+5 种基金financial support from the National Natural Science Foundation of China(No.52471220 and U2441264)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515140051)financial support from the National Natural Science Foundation of China(No.92163209)Beijing Natural Science Foundation(No.JQ22004)financial support from the National Natural Science Foundation of China(No.52476146)Guangdong Basic and Applied Basic Research Foundation(2023A1515140059,2025A1515011255).
文摘The structural modulation of metal-based heterostructure plays a vital role in achieving enhanced performances for highly efficient electrocatalysis.Here we design submonolayered Ru-modified Pd mesoporous nanosheets(Pd-Ru MNSs)with the exposure of both Pd and Ru active sites as well as the high atomic utilization of two-dimensional structure.The obtained Pd-Ru MNSs can act as a highly efficient multifunctional catalyst for hydrogen evolution reaction(HER)and alcohol oxidation reactions including ethylene glycol oxidation(EGOR)and ethanol oxidation(EOR),offering new opportunities towards the alcohol oxidation assisted hydrogen production.Specifically,Pd-Ru MNSs demonstrate excellent HER performance in alkaline electrolyte,requiring an overpotential of only 16mV to reach 10mAcm^(−2),significantly outperforming Pd mesoporous nanosheets and commercial catalysts.Density functional theory calculations reveal that the Ru sites in Pd-Ru MNSs could facilitate the water adsorption,accelerate the water dissociation,and optimize the hydrogen desorption,leading to the superior HER activity.Pd-Ru MNSs also exhibit high mass activities of 11.19 A mg^(−1)Pd for EGOR and 8.84 A mg^(−1)Pd for EOR,which is 7.8 and 9.6 times than that of commercial Pd/C,respectively.The EGOR reaction pathway over Pd-Ru MNSs was further investigated by using in situ Fourier-transform infrared spectroscopy.
基金Australian Research Council(ARC)for funding received under the ARC Discovery Project scheme(DP180102752)the financial support via the ARC DECRA scheme(DE160100715)+1 种基金the support from the Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(18SG035)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(KF2015)。
文摘Two-dimensional(2D)metal oxides and chalcogenides(MOs&MCs)have been regarded as a new class of promising electro-and photocatalysts for many important chemical reactions such as hydrogen evolution reaction,CO_(2) reduction reaction and N2 reduction reaction in virtue of their outstanding physicochemical properties.However,pristine 2D MOs&MCs generally show the relatively poor catalytic performances due to the low electrical conductivity,few active sites and fast charge recombination.Therefore,considerable efforts have been devoted to engineering 2D MOs&MCs by rational structural design and chemical modification to further improve the catalytic activities.Herein,we comprehensively review the recent advances for engineering technologies of 2D MOs&MCs,which are mainly focused on the intercalation,doping,defects creation,facet design and compositing with functional materials.Meanwhile,the relationship between morphological,physicochemical,electronic,and optical properties of 2D MOs&MCs and their electro-and photocatalytic performances is also systematically discussed.Finally,we further give the prospect and challenge of the field and possible future research directions,aiming to inspire more research for achieving high-performance 2D MOs&MCs catalysts in energy storage and conversion fields.
基金This work was financially supported by Basic Science Center Project of the National Natural Science Foundation of China(NSFC)(No.51788104)the National Key R&D Program of China(No.2018YFA0208400)+1 种基金the National Natural Science Foundation of China(Nos.51972193 and 11774191)Fok Ying-Tong Education Foundation(No.161042)。
文摘Two-dimensional(2D)heterostructures based on the combination of transition metal dichalcogenides(TMDs)and transition metal oxides(TMOs)have aroused growing attention due to their integrated merits of both components and multiple functionalities.However,nondestructive approaches of constructing TMD-TMO heterostructures are still very limited.Here,we develop a novel type of lateral TMD-TMO heterostructure(NbS2-Nb2O5-NbS2)using a simple lithography-free,direct laser-patterning technique.The perfect contact of an ultrathin TMO channel(Nb2O5)with two metallic TMDs(NbS2)electrodes guarantee strong electrical signals in a two-terminal sensor.Distinct from sensing mechanisms in separate TMOs or TMDs,this sensor works based on the modulation of surface conduction of the ultrathin TMO(Nb2O5)channel through an adsorbed layer of water molecules.The sensor thus exhibits high selectivity and ultrahigh sensitivity for room-temperature detection of NH3(ΔR/R=80%at 50 ppm),superior to the reported NH3 sensors based on 2D materials,and a positive temperature coefficient of resistance as high as 15%–20%/℃.Bending-invariant performance and high reliability are also demonstrated in flexible versions of sensors.Our work provides a new strategy of lithography-free processing of novel TMD-TMO heterostructures towards high-performance sensors,showing great potential in the applications of future portable and wearable electronics.
