The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with e...The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with elevated overpotentials,thereby imposing additional constraints on its utilization.Therefore,the pre-design and target-development of inexpensive,high-performance,and long-term stable bifunctional catalysts are urgently needed.In this work,an apically guiding dual-functional electrocatalyst(Ag-FeN_(x)-N-C)was prepared,in which a hierarchical porous nitrogen-doped carbon with three-dimensional(3D)hollow star-shaped structure is used as a substrate and high-conductivity Ag nanoparticles are coupled with iron nitride(FeN_(x))nanoparticles.Theoretical calculations indicate that the Mott-Schottky heterojunction as an inherent electric field comes from the two-phase bound of Ag and FeN_(x),of which electron accumulation in the FeN_(x)phase region and electron depletion in the Ag phase region promote orientated-guiding charge migration.The effective modulation of local electronic structures felicitously reforms the d-band electron-group distribution,and intellectually tunes the masstransfer reaction energy barriers for both ORR/OER.Additionally,the hollow star-s haped hierarchical porous structure provides an apical region for fast mass transfer.Experimental results show that the halfwave potential for ORR is 0.914 V,and the overpotential for OER is only 327 mV at 10 mA cm^(-2).A rechargeable ZAB with Ag-FeN_(x)-N-C as the air cathode demonstrates long-term cycling performance exceeding 1500 cycles(500 h),with a power density of 180 mW cm^(-2).Moreover,when employing AgFeN_(x)-N-C as the air cathode,flexible ZABs demonstrate a notable open-circuit voltage of 1.42 V and achieve a maximum power density of 65.6 mW cm^(-2).Ag-FeN_(x)-N-C shows guiding electron/mass transfer route and apical reaction microenvironment for the electrocatalyst architecture in the exploration prospects of ZABs.展开更多
Lithium-oxygen batteries(LOBs)with high energy density are a promising advanced energy storage technology.However,the slow cathodic redox kinetics during cycling causes the discharge products to fail to decompose in t...Lithium-oxygen batteries(LOBs)with high energy density are a promising advanced energy storage technology.However,the slow cathodic redox kinetics during cycling causes the discharge products to fail to decompose in time,resulting in large polarization and battery failure in a short time.Therefore,a self-supporting interconnected nanosheet array network NiCo_(2)O_(4)/MnO_(2)with a Mott-Schottky heterostructure on titanium paper(TP-NCO/MO)is ingeniously designed as an efficient cathode catalyst material for LOBs.This heterostructure can accelerate electron transfer and influence the charge transfer process during adsorption of intermediate by triggering the interface disturbance at the heterogeneous interface,thus accelerating oxygen reduction and oxygen evolution kinetics and regulating product decomposition,which is expected to solve the above problems.The meticulously designed unique structural advantages enable the TP-NCO/MO cathode catalyst to exhibit an astounding ultra-long cycle life of 800 cycles and an extraordinarily low overpotential of 0.73 V.This study utilizes a simple method to cleverly regulate the morphology of the discharge products by constructing a Mott-Schottky heterostructure,providing important reference for the design of efficient catalysts aimed at optimizing the adsorption of reaction intermediates.展开更多
The supercapacitor electrode materials suffer from structure pulverization and sluggish electrode kinetics under high current rates.Herein,a unique NiMoO_(4)@Co-B heterostructure composed of highly conductive Co-B nan...The supercapacitor electrode materials suffer from structure pulverization and sluggish electrode kinetics under high current rates.Herein,a unique NiMoO_(4)@Co-B heterostructure composed of highly conductive Co-B nanoflakes and a semiconductive NiMoO_(4) nanorod is designed as an electrode material to exert the energy storage effect on supercapacitors.The formed Mott-Schottky heterostructure is helpful to overcome the ion diffusion barrier and charge transfer resistance during charging and discharging.Moreover,this crystalline-amorphous heterogeneous phase could provide additional ion storage sites and better strain adaptability.Remarkably,the optimized NiMoO_(4)@Co-B hierarchical nanorods(the mass ratio of NiMoO_(4)/Co-B is 3:1)present greatly enhanced electrochemical characteristics compared with other components,and show superior specific capacity of 236.2 mA h g^(-1)at the current density of 0.5 A g^(-1),as well as remarked rate capability.The present work broadens the horizons of advanced electrode design with distinct heterogeneous interface in other energy storage and conversion field.展开更多
The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy （EIS）, Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The re...The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy （EIS）, Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The results show that the passivation film formed on 316L stainless steel is stable in 60% acetic acid solution from 25 ℃ to 85 ℃. As temperature increased, the polarization resistance decreased but the interface capacitance increased. There was hardly any relation between temperature and the intrinsic property semiconductor. The passivation film represents the p-semiconductor property in the potential interval of -0.5-0.1 V; represents the n-semiconductor property in the potential interval of 0.1-0.9 V; and represents the p-semiconductor property in the potential interval of 0.9-1.1 V. The voltammetry measurements show that the structure of the passivation film is stable when the temperature is lower than 55 ℃ and that its stability decreased when this temperature is exceeded.展开更多
Vacancy engineering and Mott-Schottky heterostructure can accelerate charge transfer,regulate adsorption energy of reaction intermediates,and provide additional active sites,which are regarded as valid means for impro...Vacancy engineering and Mott-Schottky heterostructure can accelerate charge transfer,regulate adsorption energy of reaction intermediates,and provide additional active sites,which are regarded as valid means for improving catalytic activity.However,the underlying mechanism of synergistic regulation of interfacial charge transfer and optimization of electrocatalytic activity by combining vacancy and Mott-Schottky junction remains unclear.Herein,the growth of a bifunctional NiCo/NiCoP Mott-Schottky electrode with abundant phosphorus vacancies on foam nickel(NF)has been synthesized through continuous phosphating and reduction processes.The obtained NiCo/NiCoP heterojunctions show remarkable OER and HER activities,and the overpotentials for OER and HER are as low as 117 and 60 mV at 10 mA/cm^(2) in 1 mol/L KOH,respectively.Moreover,as both the cathode and anode of overall water splitting,the voltage of the bifunctional NiCo/NiCoP electrocatalyst is 1.44 V at 10 mA/cm^(2),which are far exceeding the benchmark commercial electrodes.DFT theoretical calculation results confirm that the phosphorus vacancies and build-in electric field can effectively accelerate ion and electron transfer between NiCo alloy and NiCoP semiconductor,tailor the electronic structure of the metal centers and lower the Gibbs free energy of the intermediates.Furthermore,the unique self-supported integrated structure is beneficial to facilitate the exposure of the active site,avoid catalyst shedding,thus improving the activity and structural stability of NiCo/NiCoP.This study provides an avenue for the controllable synthesis and performance optimization of Mott-Schottky electrocatalysts.展开更多
The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a ...The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a self-standing porous tubular Mott-Schottky electrocatalyst is constructed by a self-template etching strategy,where amorphous WO_(x)(a-WO_(x))nano-matrix connects Co nanoparticles.This novel“Janus”electrocatalyst maximizes the Mott-Schottky effect by not only providing a highly exposed micro interface,but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process.Experimental findings and theoretical calculations reveal that Co/a-WO_(x)Mott-Schottky heterointerface triggers the electron redistribution and a build-in electric field,which can not only optimize the adsorption energy of the reaction intermediates,but also facilitate the charge transfer.Thus,Co/a-WO_(x)requires an overpotential of only 36.3 mV at 10 mA·cm^(−2)and shows a small Tafel slope of 53.9 mV·dec^(−1)as well as an excellent 200-h long-term stability.This work provides a novel design strategy for maximizing the Mott-Schottky effect on promoting alkaline HER.展开更多
Integrating heterogeneous interface through nanostructure design and interfacial modification is essential to realize strengthened interfacial polarization relaxation in electromagnetic wave absorption.However,an in-d...Integrating heterogeneous interface through nanostructure design and interfacial modification is essential to realize strengthened interfacial polarization relaxation in electromagnetic wave absorption.However,an in-depth comprehension of the interfacial polarization behavior at hetero-junction/interface is highly desired but remains a great challenge.Herein,a Mott-Schottky heterojunction consisting of honeycomb-like porous N-doped carbon confined CoP nanoparticles(CoP@HNC)is designed to elevate the interfacial polarization strength.Simultaneously,corresponding electron migration and redistribution between the heterointerface of defective carbon and CoP nanoparticles are revealed.The significant difference in the work function on both sides of heterogeneous interface boosts the interfacial polarization in high frequency region.Furthermore,the relevant spectroscopic characterizations demonstrate that electron spontaneously migrates from CoP to N-doped carbon at the heterointerface,thereby contributing to the accumulation of electron on defective carbon side and the distribution of hole on CoP side.Impressively,benefitting from the synergistic effects of three-dimensional porous conductive carbon skeleton,foreign N heteroatoms,special CoP nanoparticles,and the resultant CoP/N-doped carbon Mott-Schottky heterojunction,the CoP@HNC exhibits remarkable electromagnetic wave absorption performances with minimum reflection loss up to−60.8 dB and the maximum effective absorption bandwidth of 4.96 GHz,which is superior to most of recently reported transition metal phosphides microwave absorbing composites.The present work opens a new avenue for designing heterogeneous interface to realize strengthened microwave absorption capability and also reveals the in-depth influence of interface structure on electromagnetic wave absorption.展开更多
Searching for new promising electrocatalysts with favorable architectures allowing abundant active sites and remarkable structure stability is an urgent task for the practical application of lithium-sulfur(Li-S)batter...Searching for new promising electrocatalysts with favorable architectures allowing abundant active sites and remarkable structure stability is an urgent task for the practical application of lithium-sulfur(Li-S)batteries.Herein,inspired by the structure of natural cactus,a new efficient and robust electrocatalyst with three-dimensional(3D)hierarchical cactus-like architecture constructed by functional zero-dimensional(0D),one-dimensional(1D),and two-dimensional(2D)components is developed.The cactus-inspired catalyst(denoted as Co@NCNT/NCNS)consists of N-doped carbon nanosheets(NCNS)and standing Ndoped carbon nanotubes(NCNT)forest with embedded Co nanoparticles on the top of NCNT,which was achieved by an in situ catalytic growth technique.The unique structure design integrates the advantages of 0D Co accelerating catalytic redox reactions,1D NCNT providing a fast electron pathway,and 2D NCNS assuring strong structure stability.Especially,the rich Mott-Schottky heterointerfaces between metallic Co and semiconductive NCNT can further facilitate the electron transfer,thus improving the electrocatalyst activity.Consequently,a Li-S battery with the Co@NCNT/NCNS modified separator achieves ultralong cycle life over 4000 cycles at 2 C with ultralow capacity decay of 0.016%per cycle,much superior over that of recently reported batteries.This work provides a new strategy for developing ultra-stable catalysts towards long-life Li-S batteries.展开更多
The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave(EMW)absorption materials.However,the loss mechanism in traditional heterost...The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave(EMW)absorption materials.However,the loss mechanism in traditional heterostructures is relatively simple,guided by empirical observations,and is not monotonous.In this work,we presented a novel semiconductor-semiconductor-metal heterostructure sys-tem,Mo-MXene/Mo-metal sulfides(metal=Sn,Fe,Mn,Co,Ni,Zn,and Cu),including semiconductor junctions and Mott-Schottky junctions.By skillfully combining these distinct functional components(Mo-MXene,MoS_(2),metal sulfides),we can engineer a multiple heterogeneous interface with superior absorption capabilities,broad effective absorption bandwidths,and ultrathin matching thickness.The successful establishment of semiconductor-semiconductor-metal heterostructures gives rise to a built-in electric field that intensifies electron transfer,as confirmed by density functional theory,which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption.We detailed a successful synthesis of a series of Mo-MXene/Mo-metal sulfides featuring both semiconductor-semiconductor and semiconductor-metal interfaces.The achievements were most pronounced in Mo-MXene/Mo-Sn sulfide,which achieved remarkable reflection loss values of-70.6 dB at a matching thickness of only 1.885 mm.Radar cross-section calculations indicate that these MXene/Mo-metal sulfides have tremendous potential in practical military stealth technology.This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities.展开更多
Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem r...Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem rings conjugated by Schiff-base bond(N=C-C=N) was synthesized,tuning the bandgaps(Eg) of graphitic carbon nitride(g-C_(3) N_(4)) in the range of 1.8 400 nm) without any additive at 25℃,which is the best value among ever-reported ones.This work provides a new strategy to boost dehydrogenation photocatalysis of FA,which will be promising for practical application of H2 in future energy field.展开更多
The chemical composition and semi-conductive properties of passive film on nickel- based alloy （G3 alloy） in bicarbonate/carbonate buffer solution were investigated by Auger electron spectroscopy （AES）, X-ray phot...The chemical composition and semi-conductive properties of passive film on nickel- based alloy （G3 alloy） in bicarbonate/carbonate buffer solution were investigated by Auger electron spectroscopy （AES）, X-ray photoelectron spectroscopy （XPS）, elec- trochemical impedance spectra （EIS） and Mott-Schottky plot. AES and XPS results showed that the passive film appeared double-layer structure, in which the inner film was composed of nickel oxide, the mixed nickel-chromium-molybdenum-manganese oxides were the major component of the outer film. The electrochemical results revealed that the factors including frequency, potential, time, temperature and pH value can affect the semi-conductive property, the doping densities decreased with increasing potential and pH value, prolonging time and decreasing temperature. According to the above results, it can be concluded that the film protection on the substrate was enhanced with increasing potential and pH value, prolonging time and decreasing temperature.展开更多
基金the financial support of the National Natural Science Foundation of China(52002079,22378074,22179025 and U20A20340)the Guangdong Basic and Applied Basic Research Foundation(2022A1515140085)+2 种基金the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202209)the Guangzhou Hongmian Project(HMJH-20200012)the Foshan Introducing Innovative and Entrepreneurial Teams(1920001000108)。
文摘The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with elevated overpotentials,thereby imposing additional constraints on its utilization.Therefore,the pre-design and target-development of inexpensive,high-performance,and long-term stable bifunctional catalysts are urgently needed.In this work,an apically guiding dual-functional electrocatalyst(Ag-FeN_(x)-N-C)was prepared,in which a hierarchical porous nitrogen-doped carbon with three-dimensional(3D)hollow star-shaped structure is used as a substrate and high-conductivity Ag nanoparticles are coupled with iron nitride(FeN_(x))nanoparticles.Theoretical calculations indicate that the Mott-Schottky heterojunction as an inherent electric field comes from the two-phase bound of Ag and FeN_(x),of which electron accumulation in the FeN_(x)phase region and electron depletion in the Ag phase region promote orientated-guiding charge migration.The effective modulation of local electronic structures felicitously reforms the d-band electron-group distribution,and intellectually tunes the masstransfer reaction energy barriers for both ORR/OER.Additionally,the hollow star-s haped hierarchical porous structure provides an apical region for fast mass transfer.Experimental results show that the halfwave potential for ORR is 0.914 V,and the overpotential for OER is only 327 mV at 10 mA cm^(-2).A rechargeable ZAB with Ag-FeN_(x)-N-C as the air cathode demonstrates long-term cycling performance exceeding 1500 cycles(500 h),with a power density of 180 mW cm^(-2).Moreover,when employing AgFeN_(x)-N-C as the air cathode,flexible ZABs demonstrate a notable open-circuit voltage of 1.42 V and achieve a maximum power density of 65.6 mW cm^(-2).Ag-FeN_(x)-N-C shows guiding electron/mass transfer route and apical reaction microenvironment for the electrocatalyst architecture in the exploration prospects of ZABs.
基金the financial support from the National Natural Science Foundation of China (grant nos. 51971184 and 51931006)the Natural Science Foundation of Fujian Province of China (no. 2023J01033)+1 种基金the Fundamental Research Funds for the Central Universities of China (Xiamen University: no. 20 720 200 068)the “Double First Class” Foundation of Materials Intelligent Manufacturing Discipline of Xiamen University
文摘Lithium-oxygen batteries(LOBs)with high energy density are a promising advanced energy storage technology.However,the slow cathodic redox kinetics during cycling causes the discharge products to fail to decompose in time,resulting in large polarization and battery failure in a short time.Therefore,a self-supporting interconnected nanosheet array network NiCo_(2)O_(4)/MnO_(2)with a Mott-Schottky heterostructure on titanium paper(TP-NCO/MO)is ingeniously designed as an efficient cathode catalyst material for LOBs.This heterostructure can accelerate electron transfer and influence the charge transfer process during adsorption of intermediate by triggering the interface disturbance at the heterogeneous interface,thus accelerating oxygen reduction and oxygen evolution kinetics and regulating product decomposition,which is expected to solve the above problems.The meticulously designed unique structural advantages enable the TP-NCO/MO cathode catalyst to exhibit an astounding ultra-long cycle life of 800 cycles and an extraordinarily low overpotential of 0.73 V.This study utilizes a simple method to cleverly regulate the morphology of the discharge products by constructing a Mott-Schottky heterostructure,providing important reference for the design of efficient catalysts aimed at optimizing the adsorption of reaction intermediates.
基金supported by the National Natural Science Foundation of China(52261040,51971104)the Outstanding Postgraduate Innovation Star Project of Gansu Provincial Department of Education(2022CXZX-383)。
文摘The supercapacitor electrode materials suffer from structure pulverization and sluggish electrode kinetics under high current rates.Herein,a unique NiMoO_(4)@Co-B heterostructure composed of highly conductive Co-B nanoflakes and a semiconductive NiMoO_(4) nanorod is designed as an electrode material to exert the energy storage effect on supercapacitors.The formed Mott-Schottky heterostructure is helpful to overcome the ion diffusion barrier and charge transfer resistance during charging and discharging.Moreover,this crystalline-amorphous heterogeneous phase could provide additional ion storage sites and better strain adaptability.Remarkably,the optimized NiMoO_(4)@Co-B hierarchical nanorods(the mass ratio of NiMoO_(4)/Co-B is 3:1)present greatly enhanced electrochemical characteristics compared with other components,and show superior specific capacity of 236.2 mA h g^(-1)at the current density of 0.5 A g^(-1),as well as remarked rate capability.The present work broadens the horizons of advanced electrode design with distinct heterogeneous interface in other energy storage and conversion field.
基金the National R&D Infrastructure and Facility Development Program of China(No.2005DKA10400)
文摘The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy （EIS）, Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The results show that the passivation film formed on 316L stainless steel is stable in 60% acetic acid solution from 25 ℃ to 85 ℃. As temperature increased, the polarization resistance decreased but the interface capacitance increased. There was hardly any relation between temperature and the intrinsic property semiconductor. The passivation film represents the p-semiconductor property in the potential interval of -0.5-0.1 V; represents the n-semiconductor property in the potential interval of 0.1-0.9 V; and represents the p-semiconductor property in the potential interval of 0.9-1.1 V. The voltammetry measurements show that the structure of the passivation film is stable when the temperature is lower than 55 ℃ and that its stability decreased when this temperature is exceeded.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.22269015,22205119)Natural Science Foundation of Inner Mongolia Autonomous Region of China(Nos.2021ZD11,2019BS02015).
文摘Vacancy engineering and Mott-Schottky heterostructure can accelerate charge transfer,regulate adsorption energy of reaction intermediates,and provide additional active sites,which are regarded as valid means for improving catalytic activity.However,the underlying mechanism of synergistic regulation of interfacial charge transfer and optimization of electrocatalytic activity by combining vacancy and Mott-Schottky junction remains unclear.Herein,the growth of a bifunctional NiCo/NiCoP Mott-Schottky electrode with abundant phosphorus vacancies on foam nickel(NF)has been synthesized through continuous phosphating and reduction processes.The obtained NiCo/NiCoP heterojunctions show remarkable OER and HER activities,and the overpotentials for OER and HER are as low as 117 and 60 mV at 10 mA/cm^(2) in 1 mol/L KOH,respectively.Moreover,as both the cathode and anode of overall water splitting,the voltage of the bifunctional NiCo/NiCoP electrocatalyst is 1.44 V at 10 mA/cm^(2),which are far exceeding the benchmark commercial electrodes.DFT theoretical calculation results confirm that the phosphorus vacancies and build-in electric field can effectively accelerate ion and electron transfer between NiCo alloy and NiCoP semiconductor,tailor the electronic structure of the metal centers and lower the Gibbs free energy of the intermediates.Furthermore,the unique self-supported integrated structure is beneficial to facilitate the exposure of the active site,avoid catalyst shedding,thus improving the activity and structural stability of NiCo/NiCoP.This study provides an avenue for the controllable synthesis and performance optimization of Mott-Schottky electrocatalysts.
基金supported by the National Natural Science Foundation of China(Nos.51972349,U1801255,and 51972350)the National Natural Science Foundation of Guangdong Province(No.2022A1515011596).T。
文摘The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction(HER)depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface.Here,a self-standing porous tubular Mott-Schottky electrocatalyst is constructed by a self-template etching strategy,where amorphous WO_(x)(a-WO_(x))nano-matrix connects Co nanoparticles.This novel“Janus”electrocatalyst maximizes the Mott-Schottky effect by not only providing a highly exposed micro interface,but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process.Experimental findings and theoretical calculations reveal that Co/a-WO_(x)Mott-Schottky heterointerface triggers the electron redistribution and a build-in electric field,which can not only optimize the adsorption energy of the reaction intermediates,but also facilitate the charge transfer.Thus,Co/a-WO_(x)requires an overpotential of only 36.3 mV at 10 mA·cm^(−2)and shows a small Tafel slope of 53.9 mV·dec^(−1)as well as an excellent 200-h long-term stability.This work provides a novel design strategy for maximizing the Mott-Schottky effect on promoting alkaline HER.
基金supported by the National Natural Science Foundation of China(Nos.51872002 and 52172174)Open Project of Provincial and Ministerial Scientific Research Platform,and Fuyang Normal University(No.FSKFKT009D).
文摘Integrating heterogeneous interface through nanostructure design and interfacial modification is essential to realize strengthened interfacial polarization relaxation in electromagnetic wave absorption.However,an in-depth comprehension of the interfacial polarization behavior at hetero-junction/interface is highly desired but remains a great challenge.Herein,a Mott-Schottky heterojunction consisting of honeycomb-like porous N-doped carbon confined CoP nanoparticles(CoP@HNC)is designed to elevate the interfacial polarization strength.Simultaneously,corresponding electron migration and redistribution between the heterointerface of defective carbon and CoP nanoparticles are revealed.The significant difference in the work function on both sides of heterogeneous interface boosts the interfacial polarization in high frequency region.Furthermore,the relevant spectroscopic characterizations demonstrate that electron spontaneously migrates from CoP to N-doped carbon at the heterointerface,thereby contributing to the accumulation of electron on defective carbon side and the distribution of hole on CoP side.Impressively,benefitting from the synergistic effects of three-dimensional porous conductive carbon skeleton,foreign N heteroatoms,special CoP nanoparticles,and the resultant CoP/N-doped carbon Mott-Schottky heterojunction,the CoP@HNC exhibits remarkable electromagnetic wave absorption performances with minimum reflection loss up to−60.8 dB and the maximum effective absorption bandwidth of 4.96 GHz,which is superior to most of recently reported transition metal phosphides microwave absorbing composites.The present work opens a new avenue for designing heterogeneous interface to realize strengthened microwave absorption capability and also reveals the in-depth influence of interface structure on electromagnetic wave absorption.
基金This work was jointly supported by the National key research and development program(No.2022YFA1602700)Jiangsu Carbon Peak Carbon Neutralization Science and Technology Innovation Special Fund(No.BE2022605)+1 种基金the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(Nos.BE2020684 and BE2022332)the Fundamental Research Funds for the Central Universities。
文摘Searching for new promising electrocatalysts with favorable architectures allowing abundant active sites and remarkable structure stability is an urgent task for the practical application of lithium-sulfur(Li-S)batteries.Herein,inspired by the structure of natural cactus,a new efficient and robust electrocatalyst with three-dimensional(3D)hierarchical cactus-like architecture constructed by functional zero-dimensional(0D),one-dimensional(1D),and two-dimensional(2D)components is developed.The cactus-inspired catalyst(denoted as Co@NCNT/NCNS)consists of N-doped carbon nanosheets(NCNS)and standing Ndoped carbon nanotubes(NCNT)forest with embedded Co nanoparticles on the top of NCNT,which was achieved by an in situ catalytic growth technique.The unique structure design integrates the advantages of 0D Co accelerating catalytic redox reactions,1D NCNT providing a fast electron pathway,and 2D NCNS assuring strong structure stability.Especially,the rich Mott-Schottky heterointerfaces between metallic Co and semiconductive NCNT can further facilitate the electron transfer,thus improving the electrocatalyst activity.Consequently,a Li-S battery with the Co@NCNT/NCNS modified separator achieves ultralong cycle life over 4000 cycles at 2 C with ultralow capacity decay of 0.016%per cycle,much superior over that of recently reported batteries.This work provides a new strategy for developing ultra-stable catalysts towards long-life Li-S batteries.
基金supported by the National Natural Science Foundation of China(No.22269010,52231007,12327804,T2321003,22088101)the Jiangxi Provincial Natural Science Foundation(No.20224BAB214021)+1 种基金the Major Research Program of Jingdezhen Ceramic Industry(No.2023ZDGG002)the Ministry of Science and Technology of China(973 Project No.2021YFA1200600).
文摘The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave(EMW)absorption materials.However,the loss mechanism in traditional heterostructures is relatively simple,guided by empirical observations,and is not monotonous.In this work,we presented a novel semiconductor-semiconductor-metal heterostructure sys-tem,Mo-MXene/Mo-metal sulfides(metal=Sn,Fe,Mn,Co,Ni,Zn,and Cu),including semiconductor junctions and Mott-Schottky junctions.By skillfully combining these distinct functional components(Mo-MXene,MoS_(2),metal sulfides),we can engineer a multiple heterogeneous interface with superior absorption capabilities,broad effective absorption bandwidths,and ultrathin matching thickness.The successful establishment of semiconductor-semiconductor-metal heterostructures gives rise to a built-in electric field that intensifies electron transfer,as confirmed by density functional theory,which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption.We detailed a successful synthesis of a series of Mo-MXene/Mo-metal sulfides featuring both semiconductor-semiconductor and semiconductor-metal interfaces.The achievements were most pronounced in Mo-MXene/Mo-Sn sulfide,which achieved remarkable reflection loss values of-70.6 dB at a matching thickness of only 1.885 mm.Radar cross-section calculations indicate that these MXene/Mo-metal sulfides have tremendous potential in practical military stealth technology.This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities.
基金financially supported by Heilongjiang Science Foundation(No.LH2020B006)the National Natural Science Foundation of China(Nos.51871078,21871221 and 21602175)+1 种基金the Fundamental Research Funds for the Central Universities(No.3102017jc01001)Start-Up Funding for Class D Talent of Xi’an University of Architecture and Technology(No.1608720038)。
文摘Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem rings conjugated by Schiff-base bond(N=C-C=N) was synthesized,tuning the bandgaps(Eg) of graphitic carbon nitride(g-C_(3) N_(4)) in the range of 1.8 400 nm) without any additive at 25℃,which is the best value among ever-reported ones.This work provides a new strategy to boost dehydrogenation photocatalysis of FA,which will be promising for practical application of H2 in future energy field.
文摘The chemical composition and semi-conductive properties of passive film on nickel- based alloy （G3 alloy） in bicarbonate/carbonate buffer solution were investigated by Auger electron spectroscopy （AES）, X-ray photoelectron spectroscopy （XPS）, elec- trochemical impedance spectra （EIS） and Mott-Schottky plot. AES and XPS results showed that the passive film appeared double-layer structure, in which the inner film was composed of nickel oxide, the mixed nickel-chromium-molybdenum-manganese oxides were the major component of the outer film. The electrochemical results revealed that the factors including frequency, potential, time, temperature and pH value can affect the semi-conductive property, the doping densities decreased with increasing potential and pH value, prolonging time and decreasing temperature. According to the above results, it can be concluded that the film protection on the substrate was enhanced with increasing potential and pH value, prolonging time and decreasing temperature.
