Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(elec...Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.展开更多
Ultrasound is a powerful tool in materials processing,yet its application in constructing van der Waals(vdW)heterostructures remains under-explored.In this study,MoS_(2)and graphene—two widely studied 2D materials—w...Ultrasound is a powerful tool in materials processing,yet its application in constructing van der Waals(vdW)heterostructures remains under-explored.In this study,MoS_(2)and graphene—two widely studied 2D materials—were successfully assembled into vdW heterostructures via a convenient ultrasound-driven self-assembly approach.The morphology of the heterostructures was characterized by scanning electron microscopy(SEM),while their structural and compositional features were confirmed through x-ray diffraction(XRD),Raman spectroscopy,and x-ray photoelectron spectroscopy(XPS).Red-shifted Raman peaks and decreased binding energies in XPS spectra provided strong evidence of successful heterostructure formation.A three-stage assembly mechanism—comprising dispersion,assembly,and adjustment—is proposed,with acoustic cavitation playing a key role in driving the process.This study not only demonstrates the feasibility of synthesizing 2D heterostructures via an ultrasonic route but also lays a foundation for future scalable,energy-efficient fabrication strategies.展开更多
Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D ve...Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D vertical heterojunctions are constructed through transfer methods,inevitably introducing interfacial impurities and thus hindering detailed atomic-level studies.In this work,we have developed a clean two-step fabrication strat-egy by combining ultrahigh vacuum(UHV)molecular beam epitaxy(MBE)growth with am-bient chemical vapor deposition(CVD).We first-ly grew single crystalline graphene film on a SiC substrate under UHV condition,and then synthesized MoS_(2)films on the graphene-SiC sur-face through CVD under inert atmosphere,thus successfully realized the construction of a well-defined MoS_(2)-graphene/SiC heterojunction with clean surface.Particularly,we observed the MoS_(2)can not only grow into monolayer flakes but also form spiral structures,the latter showing layer-by-layer stacks with reduced bandgap down to~1.0 eV.展开更多
The imperative quest for renewable energy sources and advanced energy storage technologies has arisen amidst the escalating perils of climate change and dwindling fossil fuel reserves.In the realm of energy storage te...The imperative quest for renewable energy sources and advanced energy storage technologies has arisen amidst the escalating perils of climate change and dwindling fossil fuel reserves.In the realm of energy storage technologies,asymmetric supercapacitor(ASC)has garnered significant attention owing to its high energy density and power density.In the quest for advanced electrode materials for ASC,the integration of 2D layered heterostructures on hierarchical porous carbon(HPC)substrates has emerged as a promising approach to enhance the electrochemical performance.Herein,a highly innovative hierarchical NiCo LDH/MoS_(2)/HPC heterostructure was successfully synthesized using a simple two-step hydrothermal method for the electrode materials of ASC.Benefiting from the unique hierarchical heterostructure of NiCo LDH/MoS_(2)/HPC composite and the synergistic effect between the components,it reveals an exceptional specific capacitance of 2368 F/g at 0.5 A/g in a three-electrode system,which significantly exceeds that of conventional supercapacitor electrodes.Additionally,the ASC device of NiCo LDH/MoS_(2)/HPC//HPC achieves remarkable specific capacitance of 236 F/g at 0.5 A/g and an impressive energy density of 84Wh/kg at a power density of 400 W/kg,as well as superior cyclic stability.This study not only demonstrates the effectiveness of incorporating MoS_(2) and NiCo LDH into a carbon-based framework for supercapacitor applications but also opens avenues for designing more efficient energy storage devices.展开更多
The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual compon...The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.展开更多
The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge surfaces.Tuni...The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge surfaces.Tuning the adsorption strength in 2D materials to the reaction intermediates is essential for achieving high-performance LOBs.Herein,a MnS/MoS_(2) heterostructure is designed as a cathode catalyst by adjusting the adsorption behavior at the surface.Different from the toroidal-like discharge products on the MoS_(2) cathode,the MnS/MoS_(2) surface displays an improved adsorption energy to reaction species,thereby promoting the growth of the film-like discharge products.MnS can disturb the layer growth of MoS_(2),in which the stack edge plane features a strong interaction with the intermediates and limits the growth of the discharge products.Experimental and theoretical results confirm that the MnS/MoS_(2) heterostructure possesses improved electron transfer kinetics at the interface and plays an important role in the adsorption process for reaction species,which finally affects the morphology of Li_2O_(2),In consequence,the MnS/MoS_(2) heterostructure exhibits a high specific capacity of 11696.0 mA h g^(-1) and good cycle stability over 1800 h with a fixed specific capacity of 600 mA h g^(-1) at current density of100 mA g^(-1) This work provides a novel interfacial engineering strategy to enhance the performance of LOBs by tuning the adsorption properties of 2D materials.展开更多
Piezocatalytic technology demonstrates significant potential for effectively degrading pollutants and facilitating green chemical reactions,indicating promising development prospects.In this study,multi-flaw MoS_(2) n...Piezocatalytic technology demonstrates significant potential for effectively degrading pollutants and facilitating green chemical reactions,indicating promising development prospects.In this study,multi-flaw MoS_(2) nanosheets were synthesized via a hydrothermal method,and CuS nanoparticles were loaded onto their surface to form CuS/MoS_(2) piezocatalysts.The 40%CuS/MoS_(2) nanocomposite achieved an 86%degradation rate of TC under low-power(100 W,40 kHz)ultrasonic irradiation,which are 1.53 and 1.75 times higher than that of pure MoS_(2) and CuS,respectively.Furthermore,piezoresponse force microscopy(PFM)confirmed the excellent piezocatalytic performance of the composite material.The piezocurrent images revealed a significant enhancement in the piezoelectric properties of 40%CuS/MoS_(2),which is attributed to the construction of the CuS/MoS_(2) heterojunction promoting the separation of electrons and holes.This research provides a novel conceptual framework for enhancing the performance of piezocatalytic degradation.展开更多
Surface and interface engineering plays a crucial role in modulating the properties of materials,especially two-dimensional(2D)materials.Hence,a strategy,forming heterostructures with MoS_(2),is proposed to overcome t...Surface and interface engineering plays a crucial role in modulating the properties of materials,especially two-dimensional(2D)materials.Hence,a strategy,forming heterostructures with MoS_(2),is proposed to overcome the natural agglomeration of Ti_(3)C_(2)T_(x) MXene nanosheets.Most importantly,the interactions between Ti_(3)C_(2)Tx and MoS_(2) were elaborately investigated by first-principles calculations based on density functional theory(DFT)for the first time.The calculations demonstrate that van der Waals forces dominate the interface interactions of Ti_(3)C_(2)T_(x) and MoS_(2),rendering Ti_(3)C_(2)T_(x)@MoS_(2) heterostructures favorable stability.The Ti_(3)C_(2)T_(x)@MoS_(2) heterostructure composites were synthesized through a facile one-step hydrothermal method and exhibit a 2D hierarchical structure.Furthermore,the corrosion and tribological properties of epoxy composite coatings with varying proportions of Ti_(3)C_(2)T_(x)@MoS_(2) composites were studied in detail.As a result,the epoxy composite coating with 0.1 wt.%Ti_(3)C_(2)T_(x)@MoS_(2) composites(Ti_(3)C_(2)T_(x)@MoS_(2)-0.1)exhibits excellent corrosion protection and antiwear performances.The Ti_(3)C_(2)T_(x)@MoS_(2)-0.1 keeps the largest low-frequency impedance modulus(|Z|_(0.)01 Hz)and coating resistance(R_(c))during the whole immersion period.Its wear rate is 0.09μm^(3)/(Nμm)under the load of 10 N,one half of that of pure epoxy coating(EP).This work further broadens the application of MXene-based heterostructure composites.展开更多
MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Here...MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Herein,a unique MoS_(2)/FeS_(2)/C heterojunction with abundant defects and hollow structure(MFCHHS)was constructed.The synergy of defect engineering in MoS_(2),FeS_(2),and the carbon layer of MFCHHS with a larger specific surface area provides multiple storage sites of Na^(+)corresponding to the surface-controlled process.The MoS_(2)/FeS_(2)/C heterostructure and rich defects in MoS_(2) and carbon layer lower the Na^(+) diffusion energy barrier.Additionally,the construction of MoS_(2)/FeS_(2) heterojunction promotes electron transfer at the interface,accompanying with excellent conductivity of the carbon layer to facilitate reversible electrochemical reactions.The abundant defects and mismatches at the interface of MoS_(2)/FeS_(2) and MoS_(2)/C heterojunctions could relieve lattice stress and volume change sequentially.As a result,the MFCHHS anode exhibits the high capacity of 613.1 mA h g^(-1)at 0.5 A g^(-1) and 306.1 mA h g^(-1) at 20 A g^(-1).The capacity retention of 85.0%after 1400 cycles at 5.0 A g^(-1) is achieved.The density functional theory(DFT)calculation and in situ transmission electron microscope(TEM),Raman,ex-situ X-ray photon spectroscopy(XPS)studies confirm the low volume change during intercalation/deintercalation process and the efficient Na^(+)storage in the layered structure of MoS_(2) and carbon layer,as well as the defects and heterostructures in MFCHHS.We believe this work could provide an inspiration for constructing heterojunction with abundant defects to foster fast electron and Na^(+) diffusion kinetics,resulting in excellent rate capability and cycling stability.展开更多
High-performance multifunctional materials for water splitting driven by low voltage are crucial for hydrogen evolution reaction(HER),but developing such materials is challenging.Herein,a simple strategy was designed ...High-performance multifunctional materials for water splitting driven by low voltage are crucial for hydrogen evolution reaction(HER),but developing such materials is challenging.Herein,a simple strategy was designed to build a MoS_(2)/Co_(9)S_(8)/MoC@CNT-N(MCM@CNT-N)heterostructure with a large number of interfaces.Regarding the HER,the synthesized MCM@CNT-N heterostructure catalyst showed high efficiency and stable electrocatalytic performance,with a low overpotential of 174.2 mV and a small Tafel slope of 84.7 mV dec^(-1) at a current density of 10 mA cm^(-2) in 0.5 M H_(2)SO_(4).In addition to the function of heterojunctions,the excellent activity is also attributed to the introduction of Co and N atoms and the formation of carbon nanotubes.This work provides a new approach to build efficient and low-cost electrocatalysts for electrochemical reactions.展开更多
Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated pho...Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated phototransistor based on the vertical HfSe_(2)/MoS_(2)heterostructure with a broad-spectral response from near-ultraviolet to near-infrared and an efficient gate tunability for photoresponse.Under bias,the phototransistor exhibits high responsivity of up to 1.42×103A/W,and ultrahigh specific detectivity of up to 1.39×1015cm·Hz^(1/2)·W^(-1).Moreover,it can also operate under zero bias with remarkable responsivity of 10.2 A/W,relatively high specific detectivity of 1.43×1014cm·Hz^(1/2)·W^(-1),ultralow dark current of 1.22 f A,and high on/off ratio of above 105.These results should be attributed to the fact that the vertical HfSe_(2)/MoS_(2)heterostructure not only improves the broadband photoresponse of the phototransistor but also greatly enhances its sensitivity.Therefore,the heterostructure provides a promising candidate for next generation high performance phototransistors.展开更多
Designing and fabricating of heterostructured materials with long-term cycling stability and high-rate capacity for the anode of sodium-ion batteries(SIBs)still remain a great challenge.Herein,micro-flower-like MoS_(2...Designing and fabricating of heterostructured materials with long-term cycling stability and high-rate capacity for the anode of sodium-ion batteries(SIBs)still remain a great challenge.Herein,micro-flower-like MoS_(2)-modified Co_(9)S_(8)(Co_(9)S_(8)/MoS_(2))with a three-dimensional(3D)heterostructure was first obtained via a simple solvothermal synthesis followed by a solid sulfidation treatment process.As a material for the anode of SIBs,the Co_(9)S_(8)/MoS_(2)-based electrode with an initial Co/Mo molar ratio of 1/1(denoted as CM55-S)exhibits the best sodium storage performance with a boosted capacity,superior reversibility(424.5 mAh g^(-1)@2 A g^(-1)at the 1600th cycle,401.1 mAh g^(-1)@5 A g^(-1)at the 800th cycle),and an excellent rate capacity(210.1 mAh g^(-1)@20 A g^(-1)).Density functional theory(DFT)calculations confirm that the Co_(9)S_(8)/MoS_(2)heterostructure has a lower energy barrier(0.30 eV)than the pure Co_(9)S_(8)(0.53 eV).It is expected that such a heterostructured material could be an attractive candidate as the material of the anode for SIBs.展开更多
Two-dimensional(2D)moirématerials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical properties.Although great progress has been achieved,the inability...Two-dimensional(2D)moirématerials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical properties.Although great progress has been achieved,the inability to precisely and reproducibly manipulate the twist angle hinders the further development of twistronics.Here,we demonstrated an atomic force microscope(AFM)tip manipulation method to control the interlayer twist angle of epitaxial MoS_(2)/graphene heterostructure with an ultra-high accuracy better than 0.1°.Furthermore,conductive AFM and spectroscopic characterizations were conducted to show the effects of the twist angle on moirépattern wavelength,phonons and excitons.Our work provides a technique to precisely control the twist angle of 2D moirématerials,enabling the possibility to establish the phase diagrams of moiréphysics with twist angle.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22175060 and 22376062)JSPS Grant-in-Aid for Scientific Research(Nos.JP21H05235,JP22H05478 and JP22F22358)+1 种基金China Postdoctoral Science Foundation(No.2022M722867)the Key Research Project of Higher Education Institutions in Henan Province(No.23A530001).
文摘Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.
基金supported by the China Inner Mongolia Autonomous Region Directly-Undergraduate Universities Basic Research Business Fund Project:‘Environmental Protection Equipment R&D’Shared Technology and Skills Innovation Platform Construction(Grant No.NJDYWF2301).
文摘Ultrasound is a powerful tool in materials processing,yet its application in constructing van der Waals(vdW)heterostructures remains under-explored.In this study,MoS_(2)and graphene—two widely studied 2D materials—were successfully assembled into vdW heterostructures via a convenient ultrasound-driven self-assembly approach.The morphology of the heterostructures was characterized by scanning electron microscopy(SEM),while their structural and compositional features were confirmed through x-ray diffraction(XRD),Raman spectroscopy,and x-ray photoelectron spectroscopy(XPS).Red-shifted Raman peaks and decreased binding energies in XPS spectra provided strong evidence of successful heterostructure formation.A three-stage assembly mechanism—comprising dispersion,assembly,and adjustment—is proposed,with acoustic cavitation playing a key role in driving the process.This study not only demonstrates the feasibility of synthesizing 2D heterostructures via an ultrasonic route but also lays a foundation for future scalable,energy-efficient fabrication strategies.
基金support from the Natural Science Foundation of Jiangsu Province(No.BK20210124)the National Natural Science Foun-dation of China(No.12204512,No.22172152,No.21872130,No.22372193)+3 种基金the National Key Re-search and Development Program of China(No.2021YFA1502801)the joint funds from the Hefei National Synchrotron Radiation Laboratory(No.KY2060000202)We also acknowledge financial support from the CAS Project for Young Scientists in Basic Research(No.YSBR-049)the Fundamental Re-search Funds for the Central Universities(No.WK3510000013,WK2060000066).
文摘Two-dimensional(2D)heterostructures compris-ing of differently stacking atomic layers are attrac-tive owing to its flexible composition as well as the emerging new physicochemical properties.Howev-er,so far many 2D vertical heterojunctions are constructed through transfer methods,inevitably introducing interfacial impurities and thus hindering detailed atomic-level studies.In this work,we have developed a clean two-step fabrication strat-egy by combining ultrahigh vacuum(UHV)molecular beam epitaxy(MBE)growth with am-bient chemical vapor deposition(CVD).We first-ly grew single crystalline graphene film on a SiC substrate under UHV condition,and then synthesized MoS_(2)films on the graphene-SiC sur-face through CVD under inert atmosphere,thus successfully realized the construction of a well-defined MoS_(2)-graphene/SiC heterojunction with clean surface.Particularly,we observed the MoS_(2)can not only grow into monolayer flakes but also form spiral structures,the latter showing layer-by-layer stacks with reduced bandgap down to~1.0 eV.
基金supported by the National Key Research and Development Program of China(No.2021YFB3801200)the National Natural Science Foundation of China(Nos.22278051,22178044,and 22308043)the Science and Technology Innovation foundation of CNPC(No.2022DQ02–0608).
文摘The imperative quest for renewable energy sources and advanced energy storage technologies has arisen amidst the escalating perils of climate change and dwindling fossil fuel reserves.In the realm of energy storage technologies,asymmetric supercapacitor(ASC)has garnered significant attention owing to its high energy density and power density.In the quest for advanced electrode materials for ASC,the integration of 2D layered heterostructures on hierarchical porous carbon(HPC)substrates has emerged as a promising approach to enhance the electrochemical performance.Herein,a highly innovative hierarchical NiCo LDH/MoS_(2)/HPC heterostructure was successfully synthesized using a simple two-step hydrothermal method for the electrode materials of ASC.Benefiting from the unique hierarchical heterostructure of NiCo LDH/MoS_(2)/HPC composite and the synergistic effect between the components,it reveals an exceptional specific capacitance of 2368 F/g at 0.5 A/g in a three-electrode system,which significantly exceeds that of conventional supercapacitor electrodes.Additionally,the ASC device of NiCo LDH/MoS_(2)/HPC//HPC achieves remarkable specific capacitance of 236 F/g at 0.5 A/g and an impressive energy density of 84Wh/kg at a power density of 400 W/kg,as well as superior cyclic stability.This study not only demonstrates the effectiveness of incorporating MoS_(2) and NiCo LDH into a carbon-based framework for supercapacitor applications but also opens avenues for designing more efficient energy storage devices.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(2022R1A3B1078163 and 2022R1A4A1031182)supported by the KIMM institutional program(NK248E)and NST/KIMM+3 种基金supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(20024772),(RS-2023-00264860)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187508)supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,under grant no.DE-FG02-87ER13808by Northwestern University.
文摘The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.
基金supported by the National Natural Science Foundation of China (52173286, 52207249)Major basic research project of Natural Science Foundation of Shandong Province (ZR2023ZD12)+1 种基金the State Key Laboratory of Marine Resource Utilization in South China Sea (Hainan University) (MRUKF2023013)Open Program of Guangxi Key Laboratory of Information Materials (221024-K)。
文摘The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge surfaces.Tuning the adsorption strength in 2D materials to the reaction intermediates is essential for achieving high-performance LOBs.Herein,a MnS/MoS_(2) heterostructure is designed as a cathode catalyst by adjusting the adsorption behavior at the surface.Different from the toroidal-like discharge products on the MoS_(2) cathode,the MnS/MoS_(2) surface displays an improved adsorption energy to reaction species,thereby promoting the growth of the film-like discharge products.MnS can disturb the layer growth of MoS_(2),in which the stack edge plane features a strong interaction with the intermediates and limits the growth of the discharge products.Experimental and theoretical results confirm that the MnS/MoS_(2) heterostructure possesses improved electron transfer kinetics at the interface and plays an important role in the adsorption process for reaction species,which finally affects the morphology of Li_2O_(2),In consequence,the MnS/MoS_(2) heterostructure exhibits a high specific capacity of 11696.0 mA h g^(-1) and good cycle stability over 1800 h with a fixed specific capacity of 600 mA h g^(-1) at current density of100 mA g^(-1) This work provides a novel interfacial engineering strategy to enhance the performance of LOBs by tuning the adsorption properties of 2D materials.
基金Funding Projects for Young Backbone Teachers of Higher Education Institutions in Henan Province(2023GGJS020)National Natural Science Foundation of China(21901061,22171071)。
文摘Piezocatalytic technology demonstrates significant potential for effectively degrading pollutants and facilitating green chemical reactions,indicating promising development prospects.In this study,multi-flaw MoS_(2) nanosheets were synthesized via a hydrothermal method,and CuS nanoparticles were loaded onto their surface to form CuS/MoS_(2) piezocatalysts.The 40%CuS/MoS_(2) nanocomposite achieved an 86%degradation rate of TC under low-power(100 W,40 kHz)ultrasonic irradiation,which are 1.53 and 1.75 times higher than that of pure MoS_(2) and CuS,respectively.Furthermore,piezoresponse force microscopy(PFM)confirmed the excellent piezocatalytic performance of the composite material.The piezocurrent images revealed a significant enhancement in the piezoelectric properties of 40%CuS/MoS_(2),which is attributed to the construction of the CuS/MoS_(2) heterojunction promoting the separation of electrons and holes.This research provides a novel conceptual framework for enhancing the performance of piezocatalytic degradation.
基金financially supported by the National Natural Science Foundation of China(No.52075458)the Sichuan Science and Technology Program(No.2021JDRC0094)。
文摘Surface and interface engineering plays a crucial role in modulating the properties of materials,especially two-dimensional(2D)materials.Hence,a strategy,forming heterostructures with MoS_(2),is proposed to overcome the natural agglomeration of Ti_(3)C_(2)T_(x) MXene nanosheets.Most importantly,the interactions between Ti_(3)C_(2)Tx and MoS_(2) were elaborately investigated by first-principles calculations based on density functional theory(DFT)for the first time.The calculations demonstrate that van der Waals forces dominate the interface interactions of Ti_(3)C_(2)T_(x) and MoS_(2),rendering Ti_(3)C_(2)T_(x)@MoS_(2) heterostructures favorable stability.The Ti_(3)C_(2)T_(x)@MoS_(2) heterostructure composites were synthesized through a facile one-step hydrothermal method and exhibit a 2D hierarchical structure.Furthermore,the corrosion and tribological properties of epoxy composite coatings with varying proportions of Ti_(3)C_(2)T_(x)@MoS_(2) composites were studied in detail.As a result,the epoxy composite coating with 0.1 wt.%Ti_(3)C_(2)T_(x)@MoS_(2) composites(Ti_(3)C_(2)T_(x)@MoS_(2)-0.1)exhibits excellent corrosion protection and antiwear performances.The Ti_(3)C_(2)T_(x)@MoS_(2)-0.1 keeps the largest low-frequency impedance modulus(|Z|_(0.)01 Hz)and coating resistance(R_(c))during the whole immersion period.Its wear rate is 0.09μm^(3)/(Nμm)under the load of 10 N,one half of that of pure epoxy coating(EP).This work further broadens the application of MXene-based heterostructure composites.
基金the National Natural Science Foundation of China(NSFC)(22105059,22279112)the Talent Introduction Program of Hebei Agricultural University(YJ201810)+5 种基金the Youth Topnotch Talent Foundation of Hebei Provincial Universities(BJK2022023)the Natural Science Foundation of Hebei Province(B2022203018)the Fok Ying-Tong Education Foundation of China(171064)the Natural Science Foundation of Shandong Province,China(ZR2021QE192)the China Postdoctoral Science Foundation(2018M630747)the 333 Talent Program of Hebei Province(C20221018)for their support。
文摘MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Herein,a unique MoS_(2)/FeS_(2)/C heterojunction with abundant defects and hollow structure(MFCHHS)was constructed.The synergy of defect engineering in MoS_(2),FeS_(2),and the carbon layer of MFCHHS with a larger specific surface area provides multiple storage sites of Na^(+)corresponding to the surface-controlled process.The MoS_(2)/FeS_(2)/C heterostructure and rich defects in MoS_(2) and carbon layer lower the Na^(+) diffusion energy barrier.Additionally,the construction of MoS_(2)/FeS_(2) heterojunction promotes electron transfer at the interface,accompanying with excellent conductivity of the carbon layer to facilitate reversible electrochemical reactions.The abundant defects and mismatches at the interface of MoS_(2)/FeS_(2) and MoS_(2)/C heterojunctions could relieve lattice stress and volume change sequentially.As a result,the MFCHHS anode exhibits the high capacity of 613.1 mA h g^(-1)at 0.5 A g^(-1) and 306.1 mA h g^(-1) at 20 A g^(-1).The capacity retention of 85.0%after 1400 cycles at 5.0 A g^(-1) is achieved.The density functional theory(DFT)calculation and in situ transmission electron microscope(TEM),Raman,ex-situ X-ray photon spectroscopy(XPS)studies confirm the low volume change during intercalation/deintercalation process and the efficient Na^(+)storage in the layered structure of MoS_(2) and carbon layer,as well as the defects and heterostructures in MFCHHS.We believe this work could provide an inspiration for constructing heterojunction with abundant defects to foster fast electron and Na^(+) diffusion kinetics,resulting in excellent rate capability and cycling stability.
基金Thanks are given to the financial supports from the National Key R&D Program of China(2017YFB0603800)the Fundamental Research Funds for the Central Universities(2020CDJGFCL004)+4 种基金Fok Ying Tung Education Foundation(171111)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2019041,cx2018055)Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(18LHPY015)Thanks are also given to the support from school of chemistry and chemical engineering of Chongqing University for the DFT calculations.
文摘High-performance multifunctional materials for water splitting driven by low voltage are crucial for hydrogen evolution reaction(HER),but developing such materials is challenging.Herein,a simple strategy was designed to build a MoS_(2)/Co_(9)S_(8)/MoC@CNT-N(MCM@CNT-N)heterostructure with a large number of interfaces.Regarding the HER,the synthesized MCM@CNT-N heterostructure catalyst showed high efficiency and stable electrocatalytic performance,with a low overpotential of 174.2 mV and a small Tafel slope of 84.7 mV dec^(-1) at a current density of 10 mA cm^(-2) in 0.5 M H_(2)SO_(4).In addition to the function of heterojunctions,the excellent activity is also attributed to the introduction of Co and N atoms and the formation of carbon nanotubes.This work provides a new approach to build efficient and low-cost electrocatalysts for electrochemical reactions.
基金Project supported by the National Natural Science Foundation of China(Grant No.51702245)the Fundamental Research Funds for the Central Universities(Grant No.WUT2021III065JC)
文摘Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated phototransistor based on the vertical HfSe_(2)/MoS_(2)heterostructure with a broad-spectral response from near-ultraviolet to near-infrared and an efficient gate tunability for photoresponse.Under bias,the phototransistor exhibits high responsivity of up to 1.42×103A/W,and ultrahigh specific detectivity of up to 1.39×1015cm·Hz^(1/2)·W^(-1).Moreover,it can also operate under zero bias with remarkable responsivity of 10.2 A/W,relatively high specific detectivity of 1.43×1014cm·Hz^(1/2)·W^(-1),ultralow dark current of 1.22 f A,and high on/off ratio of above 105.These results should be attributed to the fact that the vertical HfSe_(2)/MoS_(2)heterostructure not only improves the broadband photoresponse of the phototransistor but also greatly enhances its sensitivity.Therefore,the heterostructure provides a promising candidate for next generation high performance phototransistors.
基金supported by ZiQoo Chemical Co.Ltd.,Japan.C.Liu gratefully acknowledges China Scholarship Council(CSC),China.
文摘Designing and fabricating of heterostructured materials with long-term cycling stability and high-rate capacity for the anode of sodium-ion batteries(SIBs)still remain a great challenge.Herein,micro-flower-like MoS_(2)-modified Co_(9)S_(8)(Co_(9)S_(8)/MoS_(2))with a three-dimensional(3D)heterostructure was first obtained via a simple solvothermal synthesis followed by a solid sulfidation treatment process.As a material for the anode of SIBs,the Co_(9)S_(8)/MoS_(2)-based electrode with an initial Co/Mo molar ratio of 1/1(denoted as CM55-S)exhibits the best sodium storage performance with a boosted capacity,superior reversibility(424.5 mAh g^(-1)@2 A g^(-1)at the 1600th cycle,401.1 mAh g^(-1)@5 A g^(-1)at the 800th cycle),and an excellent rate capacity(210.1 mAh g^(-1)@20 A g^(-1)).Density functional theory(DFT)calculations confirm that the Co_(9)S_(8)/MoS_(2)heterostructure has a lower energy barrier(0.30 eV)than the pure Co_(9)S_(8)(0.53 eV).It is expected that such a heterostructured material could be an attractive candidate as the material of the anode for SIBs.
基金Project supported by the Natioanl Natural Science Foundation of China(Grant Nos.62122084,12074412,61888102,and 11834017)。
文摘Two-dimensional(2D)moirématerials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical properties.Although great progress has been achieved,the inability to precisely and reproducibly manipulate the twist angle hinders the further development of twistronics.Here,we demonstrated an atomic force microscope(AFM)tip manipulation method to control the interlayer twist angle of epitaxial MoS_(2)/graphene heterostructure with an ultra-high accuracy better than 0.1°.Furthermore,conductive AFM and spectroscopic characterizations were conducted to show the effects of the twist angle on moirépattern wavelength,phonons and excitons.Our work provides a technique to precisely control the twist angle of 2D moirématerials,enabling the possibility to establish the phase diagrams of moiréphysics with twist angle.
