Electrochemical conversion of nitrate to valuable ammonia(NH_(3))is a green and widely used approach to NH_(3)synthesis that can be an attractive and complementary alternative to the Haber^(-)Bosch process.However,due...Electrochemical conversion of nitrate to valuable ammonia(NH_(3))is a green and widely used approach to NH_(3)synthesis that can be an attractive and complementary alternative to the Haber^(-)Bosch process.However,due to the multi-step reactions in the nitrate reduction pathway,there are still challenges in developing efficient catalysts that can selectively guide the reaction route towards NH_(3).Herein,B doping is proposed as an effective strategy to enhance nitrate conversion to NH_(3)on the Co_(3)O_(4)nanoarrays,which not only improves the electrical conductivity of Co_(3)O_(4),but also lowers the energy barrier of the potential-determining step.Such B-Co_(3)O_(4)/TM delivers a high faradaic efficiency of 94.7%and a large NH_(3)yield rate of 407.3μmol h-1 cm-2.Theoretical calculations further elucidate that the introduction of B enhances the adsorption characteristic of Co_(3)O_(4)for NO_(3)-,consequently facilitating the reduction kinetics.展开更多
The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long ...The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.展开更多
The high chloride(Cl)concentration in seawater presents a critical challenge for hydrogen production via seawater electrolysis by deactivating catalysts through active site passivation,highlighting the need for cataly...The high chloride(Cl)concentration in seawater presents a critical challenge for hydrogen production via seawater electrolysis by deactivating catalysts through active site passivation,highlighting the need for catalyst innovation.Herein,in situ boron-doped Co_(2)P/CoP(B-Co_(x)P)ultrathin nanosheet arrays are prepared as high-performance bifunctional electrocatalysts for seawater decomposition.Density functional theory(DFT)simulations,comprehensive characterizations,and in-situ analyses reveal that boron doping enhances electron density around Co centers,induces lattice distortions,and significantly elevates catalytic activity and durability.Moreover,boron doping reduces*Cl retention time at active sites—defined as the DFT-derived residence time of adsorbed Cl intermediates based on their adsorption energies—effectively mitigating Cl-induced poisoning.In a three-electrode system,B-Co_(x)P achieves exceptional bifunctional performance with overpotentials of 11 mV for hydrogen evolution reaction and 196 mV for oxygen evolution reaction to deliver 10 and 50 mA·cm^(-2),respectively—a result that showcases its superior bifunctional properties surpassing noble metal-based counterparts.In an alkaline electrolyzer,it delivers 1.56 A·cm^(-2)at 2.87 V for seawater electrolysis with outstanding stability over 500 h,preserving active site integrity via boron's robust protective role.This study defines a paradigm for designing advanced seawater electrolysis catalysts through a strategic in-situ doping approach.展开更多
By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies o...By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies of metallic carbon nanotubes are sensitive to the doping sites of the B/N pairs. The energy gaps of the doped metallic carbon nanotubes decrease with decreasing the concentration of the B/N pair not only along the tube axis but also around the tube. Moreover, the I-V characteristics and transmissions of the doped tubes are studied. Our results reveal that the conducting ability of the doped tube decreases with increasing the concentrations of the B/N pairs due to symmetry breaking of the system. This fact opens a new way to modulate band structures of metallic carbon nanotubes by doping B/N pair with suitable concentration and the novel characteristics are potentially useful in future applications.展开更多
Photocatalytic hydrogen evolution is of great importance with the proceeding of dual carbon goals,for inorganic catalysts have been explored with high efficiency.The structure and properties of oxide composites might ...Photocatalytic hydrogen evolution is of great importance with the proceeding of dual carbon goals,for inorganic catalysts have been explored with high efficiency.The structure and properties of oxide composites might take advantage of each compound and display an increased activity.In our previous study,boron doped-Cu_(3)NiBaTi_(4)O_(9)possessed a porous structure and its photocurrent response was apparent.To further verify its excellent catalytic activity,Al_(2)O_(3),and SiO_(2) were selected to replace with BaTi_(4)O_(9)to prepare different composites.The physical and chemical features of each sample were characterized with SEM,XRD,XPS,etc.to reveal their structural variations.Correspondingly,the H_(2)evolution rate was investigated with gas chromatography under the sunlight irritation.A distinct hydrogen yield was recorded with prepared samples.Further,the projected density of states analysis was taken through density functional theory calculations to appreciate the conduction band of the composite.The offered electrons during the photocatalytic process and the potential applicability of composites in the field of photocatalysis was verified.展开更多
Neutron resonance imaging(NRI)has recently emerged as an appealing technique for neutron radiography.Its complexity surpasses that of conventional transmission imaging,as it requires a high demand for both a neutron s...Neutron resonance imaging(NRI)has recently emerged as an appealing technique for neutron radiography.Its complexity surpasses that of conventional transmission imaging,as it requires a high demand for both a neutron source and detector.Consequently,the progression of NRI technology has been sluggish since its inception in the 1980s,particularly considering the limited studies analyzing the neutron energy range above keV.The white neutron source(Back-n)at the China Spallation Neutron Source(CSNS)provides favorable beam conditions for the development of the NRI technique over a wide neutron energy range from eV to MeV.Neutron-sensitive microchannel plates(MCP)have emerged as a cutting-edge tool in the field of neutron detection owing to their high temporal and spatial resolutions,high detection efficiency,and low noise.In this study,we report the development of a 10B-doped MCP detector,along with its associated electronics,data processing system,and NRI experiments at the Back-n.Individual heavy elements such as gold,silver,tungsten,and indium can be easily identified in the transmission images by their characteristic resonance peaks in the 1–100 eV energy range;the more difficult medium-weight elements such as iron,copper,and aluminum with resonance peaks in the 1–100 keV energy range can also be identified.In particular,results in the neutron energy range of dozens of keV(Aluminum)are reported here for the first time.展开更多
TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface w...TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B（Rh B）was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction（XRD）, N2 adsorption/desorption measurements, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and diffuse reflectance spectroscopy（DRS）. The photodegradation efficiencies of the two films were studied by Rh B removal in water under UV（ultraviolet） irradiation. Over 4 day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.展开更多
The dielectric ceramics with a main crystal phase of MgTiO 3 and additional crystal phase of CaTiO 3 were prepared by the conventional electronic ceramics technology. The structures of MgTiO 3 are ilmenite-type, an...The dielectric ceramics with a main crystal phase of MgTiO 3 and additional crystal phase of CaTiO 3 were prepared by the conventional electronic ceramics technology. The structures of MgTiO 3 are ilmenite-type, and belong to hexagonal syngony. The ratio of MgTiO 3 to CaTiO 3 can be adjusted to gain a zero temperature coefficient of ε r and a higher ε r for the system. The effects of B 2O 3 doping on the dielectric properties of MgTiO 3-CaTiO 3 (MCT) ceramics were investigated. The addition of B 2O 3 decreases the sintering temperature and results in rapid densification without obvious negative effect on the Q values of the system (Q=1/tan δ). B 2O 3 exists as liquid phase in the sintering process, promoting the reactions as a sintering agent.展开更多
The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathod...The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.展开更多
The design and development of a highly robust catalyst for energy production and environmental abetment are gaining much attention in the field of visible-light-driven catalysis.This work demonstrates the fabrication ...The design and development of a highly robust catalyst for energy production and environmental abetment are gaining much attention in the field of visible-light-driven catalysis.This work demonstrates the fabrication of a series of hierarchical macroporous mixed-phase TiO_(2)on the surface of B-doped g-C_(3)N_(4)(BCN).The physicochemical properties such as crystallinity,morphology,chemical environment,and optical and electronic properties of the as-synthesized materials were analysed by using different analytical techniques.PXRD and HRTEM data revealed the growth of mixed-phase TiO_(2)(anatase and rutile)on the BCN surface,mimicking P25 in the case of the best photocatalyst(TBCN-8).The catalytic activity of the as-synthesized materials was tested towards H2O_(2)production(110μmol h-1)and phenol oxidation(87% of 20 ppm phenol solution)under visible light.Higher photocurrent,lower impedance arc,and lower PL intensity suggest a lower electron-hole recombination rate in the case of TBCN-8,elucidating the best catalytic performance by the material.This work validates the facile fabrication of macroporous TiO_(2)/BCN nanocomposites and their visible-light-driven catalytic activity based on both the p-n heterojunction and Z-scheme mechanism.展开更多
Electrocatalytic nitrate reduction(NO_(3)RR)is considered an economical and effective method for the removal of N-containing pollutants,and Fe-based catalysts show great potential for numerous electrocatalytic applica...Electrocatalytic nitrate reduction(NO_(3)RR)is considered an economical and effective method for the removal of N-containing pollutants,and Fe-based catalysts show great potential for numerous electrocatalytic applications.However,for most Fe-based NO_(3)RR electrocatalysts developed to date,achieving an optimized tradeoff between activity and stability has been challenging owing to excessive agglomeration and shedding of Fe nanoparticles.展开更多
Based on DFT computations,we have systematically investigated the catalytic activity for the hydrogen evolution reaction(HER)on two-dimensional(2D)layered SnP_(3)-based systems.It is found that the monolayer SnP_(3) n...Based on DFT computations,we have systematically investigated the catalytic activity for the hydrogen evolution reaction(HER)on two-dimensional(2D)layered SnP_(3)-based systems.It is found that the monolayer SnP_(3) nanostructure can exhibit good HER activity,where the P atom with a near-zeroΔG_(H)*value serves as the most active site.展开更多
Boron and nitrogen co-doped carbon nanotubes(CNTs)were developed as a substrate material for the loading of 2-3 nm uniform Ru clusters.Combined with a theoretical and experimental comparison,it was confirmed that B do...Boron and nitrogen co-doped carbon nanotubes(CNTs)were developed as a substrate material for the loading of 2-3 nm uniform Ru clusters.Combined with a theoretical and experimental comparison,it was confirmed that B doping as well as its synergistic effect with N-doping in CNTs can effectively reduce the adsorption energy of the H intermediate at Ru site,improving the catalytic activity of the Ru cluster/CNT material for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER).Benefiting from the synergistic effect of multi element doping and a porous tubular structure,the as-formed Ru@B,N-CNTs show excellent electrocatalytic activity for both HER and OER in alkaline conditions.An overpotential of 54 mV and 315 mV is needed to achieve a current density of 10 mA cm^(-2),which exceeds requirements for commercial Pt/C and RuO_(2).Furthermore,when assembled into an electrolyzer with Ru@B,N-CNTs as both the anode and the cathode,the cell requires a cell voltage of only 1.57 V to drive a current density of 10 mA cm^(-2)in an alkaline medium and has excellent catalytic stability for over 40 hours.展开更多
Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish tran...Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.展开更多
As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical prop...As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical properties,this paper has researched the influence of tension-twisting deformation,defects,and mixed type on the electronic structure and optical properties of the armchair carbon nanotube superlattices doped cyclic alternately with B and N by using the first-principle method.Our findings show that if tension-twisting deformation is conducted,then the geometric structure,bond length,binding energy,band gap and optical properties of B,N doped carbon nanotube superlattices with defects and mixed type will be influenced.As the degree of exerted tension-twisting deformation increases,B,N doped carbon nanotube superlattices become less stable,and B,N doped carbon nanotube superlattices with defects are more stable than that with exerted tension-twisting deformations.Proper tension-twisting deformation can adjust the energy gap of the system;defects can only reduce the energy gap,enhancing the system metallicity;while the mixed type of 5%tension,twisting angle of 15° and atomic defects will significantly increase the energy gap of the system.From the perspective of optical properties,doped carbon nanotubes may transform the system from metallicity into semi-conductivity.展开更多
基金supported by the National Natural Science Foundation of China(No.21876117)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2021YB05).
文摘Electrochemical conversion of nitrate to valuable ammonia(NH_(3))is a green and widely used approach to NH_(3)synthesis that can be an attractive and complementary alternative to the Haber^(-)Bosch process.However,due to the multi-step reactions in the nitrate reduction pathway,there are still challenges in developing efficient catalysts that can selectively guide the reaction route towards NH_(3).Herein,B doping is proposed as an effective strategy to enhance nitrate conversion to NH_(3)on the Co_(3)O_(4)nanoarrays,which not only improves the electrical conductivity of Co_(3)O_(4),but also lowers the energy barrier of the potential-determining step.Such B-Co_(3)O_(4)/TM delivers a high faradaic efficiency of 94.7%and a large NH_(3)yield rate of 407.3μmol h-1 cm-2.Theoretical calculations further elucidate that the introduction of B enhances the adsorption characteristic of Co_(3)O_(4)for NO_(3)-,consequently facilitating the reduction kinetics.
基金financially supported by the National Natural Science Foundation of China(Project numbers.51834004,51774076,51704062)the Fundamental Research Funds for the Central Universities(N2025019)。
文摘The extended cycle life of cells is often sacrificed at the expense of high specific energy for high-nickel materials.Cation doping is a promising method to build high-nickel cathode with high energy density and long cycle life.Herein,a trace amount of Mg-B co-doping in LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2(NMC622)is investigated in this work,which shows improved structural and electrochemical stability of 1%Mg-0.5%B co-doped material at both 30 and 55℃in coin-cell.Comprehensive chemical composition,structural,and surface analysis are carried out in this paper.It was found that all the selected materials have a similar composition to the target.Moreover,Mg and B doping have different effects on the crystal structural change of NMC622,to be more specific,the c-lattice parameter increases with Mg doping,while the Li^(+)/Ni^(2+)mixing content increases when B was incorporated into the lattice.Furthermore,the microstructure of primary particles was changed by B doping significantly as confirmed by the SEM images.There were marginal benefits in terms of structural and electrochemical stability of materials introduced by Mg or B sole doping.In comparison,incorporating a suitable amount of both Mg and B into NMC622,we found the capacity retention of cells was noticeably improved by reducing the impedance growth and preventing cation mixing during cycling.This study demonstrates the importance of co-incorporation of Mg,B,and optimizing the co-dopant content to stabilize NMC622 as cathode for lithium-ion batteries.
基金supported by the National Natural Science Foundation of China(No.U24A20550,52273264)Youth Science Foundation Project ofChina(No.22409056)+1 种基金the Key Project of the Heilongjiang Provincial Natural Science Foundation(No.ZD2024B001)the Excellent Youth Project ofHeilongjiang Provincial Natural Science Foundation of China(No.LH2019B020).
文摘The high chloride(Cl)concentration in seawater presents a critical challenge for hydrogen production via seawater electrolysis by deactivating catalysts through active site passivation,highlighting the need for catalyst innovation.Herein,in situ boron-doped Co_(2)P/CoP(B-Co_(x)P)ultrathin nanosheet arrays are prepared as high-performance bifunctional electrocatalysts for seawater decomposition.Density functional theory(DFT)simulations,comprehensive characterizations,and in-situ analyses reveal that boron doping enhances electron density around Co centers,induces lattice distortions,and significantly elevates catalytic activity and durability.Moreover,boron doping reduces*Cl retention time at active sites—defined as the DFT-derived residence time of adsorbed Cl intermediates based on their adsorption energies—effectively mitigating Cl-induced poisoning.In a three-electrode system,B-Co_(x)P achieves exceptional bifunctional performance with overpotentials of 11 mV for hydrogen evolution reaction and 196 mV for oxygen evolution reaction to deliver 10 and 50 mA·cm^(-2),respectively—a result that showcases its superior bifunctional properties surpassing noble metal-based counterparts.In an alkaline electrolyzer,it delivers 1.56 A·cm^(-2)at 2.87 V for seawater electrolysis with outstanding stability over 500 h,preserving active site integrity via boron's robust protective role.This study defines a paradigm for designing advanced seawater electrolysis catalysts through a strategic in-situ doping approach.
基金supported by the Major Research Plan from the Ministry of Science and Technology of China (Grant No. 2011CB921900)the China Postdoctoral Science Special Foundation (Grant No. 201003009)+2 种基金the China Postdoctoral Science Foundation (GrantNo. 20090460145)the Fundamental Research Funds for the Central Universities (Grant No. 201012200053)the Science and Technology Program of Hunan Province of China (Grant No. 2010DFJ411)
文摘By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies of metallic carbon nanotubes are sensitive to the doping sites of the B/N pairs. The energy gaps of the doped metallic carbon nanotubes decrease with decreasing the concentration of the B/N pair not only along the tube axis but also around the tube. Moreover, the I-V characteristics and transmissions of the doped tubes are studied. Our results reveal that the conducting ability of the doped tube decreases with increasing the concentrations of the B/N pairs due to symmetry breaking of the system. This fact opens a new way to modulate band structures of metallic carbon nanotubes by doping B/N pair with suitable concentration and the novel characteristics are potentially useful in future applications.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2021D01A03)Key Research and Development Projects of Xinjiang Uygur Autonomous Region(2022B02038)+1 种基金Special Training Program for Scientific and Technological Talents of Ethnic Minorities in Xinjiang Uygur Autonomous Region(2020D03025)Project of Tian chi talent leader in Xinjiang Uygur Autonomous Region(2022).
文摘Photocatalytic hydrogen evolution is of great importance with the proceeding of dual carbon goals,for inorganic catalysts have been explored with high efficiency.The structure and properties of oxide composites might take advantage of each compound and display an increased activity.In our previous study,boron doped-Cu_(3)NiBaTi_(4)O_(9)possessed a porous structure and its photocurrent response was apparent.To further verify its excellent catalytic activity,Al_(2)O_(3),and SiO_(2) were selected to replace with BaTi_(4)O_(9)to prepare different composites.The physical and chemical features of each sample were characterized with SEM,XRD,XPS,etc.to reveal their structural variations.Correspondingly,the H_(2)evolution rate was investigated with gas chromatography under the sunlight irritation.A distinct hydrogen yield was recorded with prepared samples.Further,the projected density of states analysis was taken through density functional theory calculations to appreciate the conduction band of the composite.The offered electrons during the photocatalytic process and the potential applicability of composites in the field of photocatalysis was verified.
基金supported by the National Natural Science Foundation of China(No.12035017)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030074)。
文摘Neutron resonance imaging(NRI)has recently emerged as an appealing technique for neutron radiography.Its complexity surpasses that of conventional transmission imaging,as it requires a high demand for both a neutron source and detector.Consequently,the progression of NRI technology has been sluggish since its inception in the 1980s,particularly considering the limited studies analyzing the neutron energy range above keV.The white neutron source(Back-n)at the China Spallation Neutron Source(CSNS)provides favorable beam conditions for the development of the NRI technique over a wide neutron energy range from eV to MeV.Neutron-sensitive microchannel plates(MCP)have emerged as a cutting-edge tool in the field of neutron detection owing to their high temporal and spatial resolutions,high detection efficiency,and low noise.In this study,we report the development of a 10B-doped MCP detector,along with its associated electronics,data processing system,and NRI experiments at the Back-n.Individual heavy elements such as gold,silver,tungsten,and indium can be easily identified in the transmission images by their characteristic resonance peaks in the 1–100 eV energy range;the more difficult medium-weight elements such as iron,copper,and aluminum with resonance peaks in the 1–100 keV energy range can also be identified.In particular,results in the neutron energy range of dozens of keV(Aluminum)are reported here for the first time.
基金supported by the National Science Funds for Creative Research Groups of China (No. 51421006)the National Major Projects of Water Pollution Control and Management Technology (No. 2017ZX07204003)+2 种基金the National Key Plan for Research and Development of China (2016YFC0502203)the Key Program of National Natural Science Foundation of China (No. 91647206)the Qing Lan Project of Jiangsu Province, and PAPD
文摘TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B（Rh B）was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction（XRD）, N2 adsorption/desorption measurements, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and diffuse reflectance spectroscopy（DRS）. The photodegradation efficiencies of the two films were studied by Rh B removal in water under UV（ultraviolet） irradiation. Over 4 day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.
文摘The dielectric ceramics with a main crystal phase of MgTiO 3 and additional crystal phase of CaTiO 3 were prepared by the conventional electronic ceramics technology. The structures of MgTiO 3 are ilmenite-type, and belong to hexagonal syngony. The ratio of MgTiO 3 to CaTiO 3 can be adjusted to gain a zero temperature coefficient of ε r and a higher ε r for the system. The effects of B 2O 3 doping on the dielectric properties of MgTiO 3-CaTiO 3 (MCT) ceramics were investigated. The addition of B 2O 3 decreases the sintering temperature and results in rapid densification without obvious negative effect on the Q values of the system (Q=1/tan δ). B 2O 3 exists as liquid phase in the sintering process, promoting the reactions as a sintering agent.
基金supported by the National Natural Science Foundation of China(Nos.22125903 and 51872283)Dalian Innovation Support Plan for High Level Talents(No.2019RT09)+2 种基金Dalian National Laboratory for Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(Nos.DNL201912,DNL201915,DNL202016,and DNL202019)DICP(No.DICP I2020032)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Nos.YLU‐DNL Fund 2021002 and YLU‐DNL 2021009).
文摘The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.
文摘The design and development of a highly robust catalyst for energy production and environmental abetment are gaining much attention in the field of visible-light-driven catalysis.This work demonstrates the fabrication of a series of hierarchical macroporous mixed-phase TiO_(2)on the surface of B-doped g-C_(3)N_(4)(BCN).The physicochemical properties such as crystallinity,morphology,chemical environment,and optical and electronic properties of the as-synthesized materials were analysed by using different analytical techniques.PXRD and HRTEM data revealed the growth of mixed-phase TiO_(2)(anatase and rutile)on the BCN surface,mimicking P25 in the case of the best photocatalyst(TBCN-8).The catalytic activity of the as-synthesized materials was tested towards H2O_(2)production(110μmol h-1)and phenol oxidation(87% of 20 ppm phenol solution)under visible light.Higher photocurrent,lower impedance arc,and lower PL intensity suggest a lower electron-hole recombination rate in the case of TBCN-8,elucidating the best catalytic performance by the material.This work validates the facile fabrication of macroporous TiO_(2)/BCN nanocomposites and their visible-light-driven catalytic activity based on both the p-n heterojunction and Z-scheme mechanism.
基金supported by the National Natural Science Foundation of China(Grant No.52172291 and 52122312)“Shuguang Program”supported by the Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22SG31)+1 种基金State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(Donghua University)JC would specially thank supports from the Australian Research Council(DP220101290)and ANFFs-Materials Node at UOW。
文摘Electrocatalytic nitrate reduction(NO_(3)RR)is considered an economical and effective method for the removal of N-containing pollutants,and Fe-based catalysts show great potential for numerous electrocatalytic applications.However,for most Fe-based NO_(3)RR electrocatalysts developed to date,achieving an optimized tradeoff between activity and stability has been challenging owing to excessive agglomeration and shedding of Fe nanoparticles.
基金supported by the China by NSFC(21673094,21673093 and 21573090)the Science and Technology Research Program of Education Department of Jilin Province(JJKH20190121KJ)the Jilin Province Science and Technology Development Plan(20170101175JC).
文摘Based on DFT computations,we have systematically investigated the catalytic activity for the hydrogen evolution reaction(HER)on two-dimensional(2D)layered SnP_(3)-based systems.It is found that the monolayer SnP_(3) nanostructure can exhibit good HER activity,where the P atom with a near-zeroΔG_(H)*value serves as the most active site.
基金supported by Natural Science Foundation of Jilin Province,China(Grant No.20210101120JC).
文摘Boron and nitrogen co-doped carbon nanotubes(CNTs)were developed as a substrate material for the loading of 2-3 nm uniform Ru clusters.Combined with a theoretical and experimental comparison,it was confirmed that B doping as well as its synergistic effect with N-doping in CNTs can effectively reduce the adsorption energy of the H intermediate at Ru site,improving the catalytic activity of the Ru cluster/CNT material for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER).Benefiting from the synergistic effect of multi element doping and a porous tubular structure,the as-formed Ru@B,N-CNTs show excellent electrocatalytic activity for both HER and OER in alkaline conditions.An overpotential of 54 mV and 315 mV is needed to achieve a current density of 10 mA cm^(-2),which exceeds requirements for commercial Pt/C and RuO_(2).Furthermore,when assembled into an electrolyzer with Ru@B,N-CNTs as both the anode and the cathode,the cell requires a cell voltage of only 1.57 V to drive a current density of 10 mA cm^(-2)in an alkaline medium and has excellent catalytic stability for over 40 hours.
基金the financial support from the National Key Projects for Fundamental Research and Development of China(2021YFA1500803)the National Natural Science Foundation of China(No.22209190)+2 种基金the Central China Normal University(2020CXZZ023)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Beijing Natural Science Foundation(2222081).S.O.appreciates the financial support from the“Guizi Scholar”Program of Central China Normal University and the fellowship of China Postdoctoral Science Foundation(No.GZC20241766,2024M753304).
文摘Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.
基金supported by the National Natural Science Foundation of China(No.51371049)the Natural Science Foundation of Liaoning Province(No.20102173)
文摘As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical properties,this paper has researched the influence of tension-twisting deformation,defects,and mixed type on the electronic structure and optical properties of the armchair carbon nanotube superlattices doped cyclic alternately with B and N by using the first-principle method.Our findings show that if tension-twisting deformation is conducted,then the geometric structure,bond length,binding energy,band gap and optical properties of B,N doped carbon nanotube superlattices with defects and mixed type will be influenced.As the degree of exerted tension-twisting deformation increases,B,N doped carbon nanotube superlattices become less stable,and B,N doped carbon nanotube superlattices with defects are more stable than that with exerted tension-twisting deformations.Proper tension-twisting deformation can adjust the energy gap of the system;defects can only reduce the energy gap,enhancing the system metallicity;while the mixed type of 5%tension,twisting angle of 15° and atomic defects will significantly increase the energy gap of the system.From the perspective of optical properties,doped carbon nanotubes may transform the system from metallicity into semi-conductivity.
