To design the high-energy-density Li-ion batteries, the anode materials with high specific capacity haveattracted much attention. In this work, we adopt the first principles calculations to investigate the pos-sibilit...To design the high-energy-density Li-ion batteries, the anode materials with high specific capacity haveattracted much attention. In this work, we adopt the first principles calculations to investigate the pos-sibility of a new two dimensional boron material, named Be, as anode material for Li-ion batteries. Thecalculated results show that the maximum theoretical specific capacity of Bc is 1653mAh g-1 （LiBl.s）.Additionally, the energy barriers of Li ion and Li vacancy diffusion are 330 meV and 110 meV, respec-tively, which imply fast charge and discharge ability for B6 as an anode material. The theoretical findingsreported in this work suggest that BG is a potential candidate as anode material of high-energy-density Li-ion batteries.展开更多
In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of...In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of phase change was proposed.The detonation wave model was validated through a comparative analysis with shock tube experiments,which revealed that the maximum deviation in the calculated peak detonation pressure was 8%based on various initial pressures.Upon iterative calculations,the eigenvalue detonation velocity of the boron-based gel propellant under default working conditions was obtained as 1831.5 m/s.Subsequently,the refined model was used to study the structure and characteristics of the detonation wave flow field.The effects of incoming flow conditions,fuel parameters,and initial operating state on the detonation wave flow field of the propellant were investigated numerically.The findings revealed that stable and self-sustaining propagation of the detonation wave can be achieved only when its propagation velocity matches the eigenvalue detonation velocity.Note that an increase in initial temperature resulted in elevated gas phase temperature,density,detonation pressure,and particle phase temperature.An increase in boron content within the gel propellant increased the gas phase temperature but decreased the gas phase density and detonation pressure.At the Chapman-Jouguet(CJ)plane,the gas phase temperature and density,along with the particle phase temperature and detonation pressure,reached their peak values when the oxidizer reacted with the propellant in accordance with the stoichiometric ratio.展开更多
Boron-based metal-free catalysts for oxidative dehydrogenation of propane(ODHP)have drawn great attention in both academia and industry due to their impressive activity and olefin selectivity.Herein,the SiO2 and B2O3 ...Boron-based metal-free catalysts for oxidative dehydrogenation of propane(ODHP)have drawn great attention in both academia and industry due to their impressive activity and olefin selectivity.Herein,the SiO2 and B2O3 sequentially coated honeycomb cordierite catalyst is designed by a two-step wash-coat method with different B2O3 loadings(0.1%–10%)and calcination temperatures(600,700,800℃).SiO2 obtained by TEOS hydrolysis acts as a media layer to bridge the cordierite substrate and boron oxide via abundant Si\\OH groups.The welldeveloped straight channels of honeycomb cordierite make it possible to carry out the reactor under high gas hourly space velocity(GHSV)and the thin wash-coated B2O3 layer can effectively facilitate the pore diffusion on the catalyst.The prepared B2O3/SiO2@HC monolithic catalyst exhibits good catalytic performance at low boron oxide loading and achieves excellent propylene selectivity(86.0%),olefin selectivity(97.6%,propylene and ethylene)and negligible CO2(0.1%)at 16.9%propane conversion under high GHSV of 345,600 ml·(g B2O3)^-1·h^-1,leading to a high propylene space time yield of 15.7 g C3H6·(g B2O3)^-1·h^-1 by suppressing the overoxidation.The obtained results strongly indicate that the boron-based monolithic catalyst can be properly fabricated to warrant the high activity and high throughput with its high gas/surface ratio and straight channels.展开更多
The discovery of the high activity and selectivity of boron-based catalysts for oxidative dehydrogenation(ODH)of alkanes to olefins has attracted significant attention in the exploration of a new method for the synthe...The discovery of the high activity and selectivity of boron-based catalysts for oxidative dehydrogenation(ODH)of alkanes to olefins has attracted significant attention in the exploration of a new method for the synthesis of highly active and selective catalysts.Herein,we describe the synthesis of porous boron-doped silica nanofibers(PBSNs)100-150 nm in diameter by electrospinning and the study of their catalytic performance.The electrospinning synthesis of the catalyst ensures the uniform dispersion and stability of the boron species on the open silica fiber framework.The one-dimensional nanofibers with open pore structures not only prevented diffusion limitation but also guaranteed high catalytic activity at high weight hourly space velocity(WHSV)in the ODH of alkanes.Compared to other supported boron oxide catalysts,PBSN catalysts showed higher olefin selectivity and stability.The presence of Si-OH groups in silica-supported boron catalysts may cause low propylene selectivity during the ODH of propane.When the ODH conversion of ethane reached 44.3%,the selectivity and productivity of ethylene were 84%and 44.2%g_(cat)^(-1)s^(-1),respectively.In the case of propane ODH,the conversion,selectivity of olefins,and productivity of propylene are 19.2%,90%,and 76.6 jimol g_(cat)^(-1)s^(-1),respectively.No significant variations in the conversion and product selectivity occurred during 20 h of operation at a high WHSV of 84.6 h^(-1).Transient analysis and kinetic experiments indicated that the activation of O2 was influenced by alkanes during the ODH reaction.展开更多
The advance of space technology is deeply affected by the breakthrough of high-performance fuels.Hypergolic ionic liquids(HILs)are one of the most potential fuels for bipropellant systems.However,high viscosity value ...The advance of space technology is deeply affected by the breakthrough of high-performance fuels.Hypergolic ionic liquids(HILs)are one of the most potential fuels for bipropellant systems.However,high viscosity value and low specific impulse of traditional N-based HILs limit their application.Recently,boron-based HILs with low viscosity become the new candidates,and their derivatives are also found to promote the hypergolicity as additives in HILs.Here,the synthesis,physical chemical properties and thermal performance of boron-based HILs and HILadditive system are reviewed.展开更多
To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper o...To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper oxide,and bismuth trioxide powders were dispersed in the dispersed phase (DMF) using F_(2602) as a binder,and the construction of two-component B-CuO,B-Bi_(2)O_(3),three-component microcomposite,and three-component macro-composite sticks were realized with the help of double nozzle direct ink writing (DIW) technique respectively.The resulting sticks were ignited by a nichrome wire energized with a direct current,and a high-speed camera system was used to record the combustion behavior of the sticks,mark the flame position,and calculate the rate of ignition.The results showed that the B-CuO stick burning rate (42.11 mm·s^(-1)) was much higher than that of B-Bi_(2)O_(3)(17.84 mm·s^(-1)).The formulation with the highest CuO content (ω_(CuO)=58.7%) in the microscale composite of the sticks also had the fastest burning rate of 60.59 mm·s^(-1),as the CuO content decreased (ω_(CuO)=43.5%,29.3%),its burning rate decreased to 34.78 mm·s^(-1),37.97 mm·s^(-1).The stick with the highest copper oxide content(ω_(CuO)=60%) also possessed the highest burning rate (48.84 mm·s^(-1)) in the macro-composite sticks,and the burning rates of the macro-composite sticks with component spacing of 0.1 mm,0.2 mm,and 0.5 mm were 43.34 mm·s^(-1),48.84 mm·s^(-1),and 40.76 mm·s^(-1).展开更多
Boron-based solid fuel is considered advantageous for ducted rocket applications due to its high energy density and dual-stage combustion process.Nonetheless,its performance is constrained by the formation of a protec...Boron-based solid fuel is considered advantageous for ducted rocket applications due to its high energy density and dual-stage combustion process.Nonetheless,its performance is constrained by the formation of a protective boron oxide layer.In the current study,iron nanoparticles are incorporated into boron-based solid fuel to enhance boron's burning.Paraffin wax serves as the primary fuel and binder,while gaseous oxygen is used as an oxidizer.Four different solid fuel combinations were investigated in the experiment:pure paraffin wax,paraffin wax mixed with boron particles,and paraffin wax mixed with boron alongside 10%and 20%iron particles.The main effort of the research is to assess their combustion characteristics,focusing on regression rate and combustion efficiency.While the inclusion of 10%iron particles resulted in a decrease in the regression rate,it led to an improvement in combustion efficiency by reducing the residual active boron content in the condensed combustion product by~60%.Furthermore,it was observed that increasing the proportion of iron particles to 20%further enhanced combustion efficiency to approximately 4%.The entire assessment has been carried out using a lab-scale hybrid propellant ducted rocket motor configuration having an inlet duct on regenerative concept with the secondary combustor.In the present investigation oxygen is injected both in the primary and the secondary combustor,whereas in the existing actual/lab-scale ducted rockets,an energized air is introduced in the secondary combustor.It serves as an economical system for the preliminary investigation of solid fuel impregnated with boron particles.It is expected that the present study could prove valuable strategies for future applications of boron-based hybrid propellants in ducted rocket systems.展开更多
基金financially supported by the New Energy Project for Electric Vehicle of National Key Research and Development Program (2016YFB0100200)the National Natural Science Foundation of China (51671004,U1764255)+1 种基金National Postdoctoral Program for Innovative Talents (BX201700001)supported by High-performance Computing Platform of Peking University
文摘To design the high-energy-density Li-ion batteries, the anode materials with high specific capacity haveattracted much attention. In this work, we adopt the first principles calculations to investigate the pos-sibility of a new two dimensional boron material, named Be, as anode material for Li-ion batteries. Thecalculated results show that the maximum theoretical specific capacity of Bc is 1653mAh g-1 （LiBl.s）.Additionally, the energy barriers of Li ion and Li vacancy diffusion are 330 meV and 110 meV, respec-tively, which imply fast charge and discharge ability for B6 as an anode material. The theoretical findingsreported in this work suggest that BG is a potential candidate as anode material of high-energy-density Li-ion batteries.
基金supported by the Science and Technology Innovation Program of Hunan Province(No.2022RC3045)the Hunan Provincial Natural Science Foundation of China(No.2023JJ30635)the National Natural Science Foundation of China(No.12302394).
文摘In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of phase change was proposed.The detonation wave model was validated through a comparative analysis with shock tube experiments,which revealed that the maximum deviation in the calculated peak detonation pressure was 8%based on various initial pressures.Upon iterative calculations,the eigenvalue detonation velocity of the boron-based gel propellant under default working conditions was obtained as 1831.5 m/s.Subsequently,the refined model was used to study the structure and characteristics of the detonation wave flow field.The effects of incoming flow conditions,fuel parameters,and initial operating state on the detonation wave flow field of the propellant were investigated numerically.The findings revealed that stable and self-sustaining propagation of the detonation wave can be achieved only when its propagation velocity matches the eigenvalue detonation velocity.Note that an increase in initial temperature resulted in elevated gas phase temperature,density,detonation pressure,and particle phase temperature.An increase in boron content within the gel propellant increased the gas phase temperature but decreased the gas phase density and detonation pressure.At the Chapman-Jouguet(CJ)plane,the gas phase temperature and density,along with the particle phase temperature and detonation pressure,reached their peak values when the oxidizer reacted with the propellant in accordance with the stoichiometric ratio.
基金supported by State Key Program of National Natural Science Foundation of China(21733002)Joint Sino-German Research Project(21761132011)Cheung Kong Scholars Programme of China(T2015036)。
文摘Boron-based metal-free catalysts for oxidative dehydrogenation of propane(ODHP)have drawn great attention in both academia and industry due to their impressive activity and olefin selectivity.Herein,the SiO2 and B2O3 sequentially coated honeycomb cordierite catalyst is designed by a two-step wash-coat method with different B2O3 loadings(0.1%–10%)and calcination temperatures(600,700,800℃).SiO2 obtained by TEOS hydrolysis acts as a media layer to bridge the cordierite substrate and boron oxide via abundant Si\\OH groups.The welldeveloped straight channels of honeycomb cordierite make it possible to carry out the reactor under high gas hourly space velocity(GHSV)and the thin wash-coated B2O3 layer can effectively facilitate the pore diffusion on the catalyst.The prepared B2O3/SiO2@HC monolithic catalyst exhibits good catalytic performance at low boron oxide loading and achieves excellent propylene selectivity(86.0%),olefin selectivity(97.6%,propylene and ethylene)and negligible CO2(0.1%)at 16.9%propane conversion under high GHSV of 345,600 ml·(g B2O3)^-1·h^-1,leading to a high propylene space time yield of 15.7 g C3H6·(g B2O3)^-1·h^-1 by suppressing the overoxidation.The obtained results strongly indicate that the boron-based monolithic catalyst can be properly fabricated to warrant the high activity and high throughput with its high gas/surface ratio and straight channels.
文摘The discovery of the high activity and selectivity of boron-based catalysts for oxidative dehydrogenation(ODH)of alkanes to olefins has attracted significant attention in the exploration of a new method for the synthesis of highly active and selective catalysts.Herein,we describe the synthesis of porous boron-doped silica nanofibers(PBSNs)100-150 nm in diameter by electrospinning and the study of their catalytic performance.The electrospinning synthesis of the catalyst ensures the uniform dispersion and stability of the boron species on the open silica fiber framework.The one-dimensional nanofibers with open pore structures not only prevented diffusion limitation but also guaranteed high catalytic activity at high weight hourly space velocity(WHSV)in the ODH of alkanes.Compared to other supported boron oxide catalysts,PBSN catalysts showed higher olefin selectivity and stability.The presence of Si-OH groups in silica-supported boron catalysts may cause low propylene selectivity during the ODH of propane.When the ODH conversion of ethane reached 44.3%,the selectivity and productivity of ethylene were 84%and 44.2%g_(cat)^(-1)s^(-1),respectively.In the case of propane ODH,the conversion,selectivity of olefins,and productivity of propylene are 19.2%,90%,and 76.6 jimol g_(cat)^(-1)s^(-1),respectively.No significant variations in the conversion and product selectivity occurred during 20 h of operation at a high WHSV of 84.6 h^(-1).Transient analysis and kinetic experiments indicated that the activation of O2 was influenced by alkanes during the ODH reaction.
基金support of the National Natural Science Foundation of China(21905069,21703218)the Shenzhen Science and Technology Innovation Committee(JCYJ20180507183907224 and KQTD20170809110344233)+1 种基金Economic,Trade and Information Commission of Shenzhen Municipality through the Graphene Manufacture Innovation Center(201901161514)Guangdong Province Covid-19 Pandemic Control Research Fund 2020KZDZX1220。
文摘The advance of space technology is deeply affected by the breakthrough of high-performance fuels.Hypergolic ionic liquids(HILs)are one of the most potential fuels for bipropellant systems.However,high viscosity value and low specific impulse of traditional N-based HILs limit their application.Recently,boron-based HILs with low viscosity become the new candidates,and their derivatives are also found to promote the hypergolicity as additives in HILs.Here,the synthesis,physical chemical properties and thermal performance of boron-based HILs and HILadditive system are reviewed.
基金supported by the Graduate Education Innovation Project of Shanxi Province(Grant No.2022Y650)the National Natural Science Foundation of China(Grant No.22275170)。
文摘To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper oxide,and bismuth trioxide powders were dispersed in the dispersed phase (DMF) using F_(2602) as a binder,and the construction of two-component B-CuO,B-Bi_(2)O_(3),three-component microcomposite,and three-component macro-composite sticks were realized with the help of double nozzle direct ink writing (DIW) technique respectively.The resulting sticks were ignited by a nichrome wire energized with a direct current,and a high-speed camera system was used to record the combustion behavior of the sticks,mark the flame position,and calculate the rate of ignition.The results showed that the B-CuO stick burning rate (42.11 mm·s^(-1)) was much higher than that of B-Bi_(2)O_(3)(17.84 mm·s^(-1)).The formulation with the highest CuO content (ω_(CuO)=58.7%) in the microscale composite of the sticks also had the fastest burning rate of 60.59 mm·s^(-1),as the CuO content decreased (ω_(CuO)=43.5%,29.3%),its burning rate decreased to 34.78 mm·s^(-1),37.97 mm·s^(-1).The stick with the highest copper oxide content(ω_(CuO)=60%) also possessed the highest burning rate (48.84 mm·s^(-1)) in the macro-composite sticks,and the burning rates of the macro-composite sticks with component spacing of 0.1 mm,0.2 mm,and 0.5 mm were 43.34 mm·s^(-1),48.84 mm·s^(-1),and 40.76 mm·s^(-1).
基金the Centre of Excellence in Propulsion Systems,Alliance University,Bangalore,for providing funds(Grant No.-AU/DeanR/RC/2022)。
文摘Boron-based solid fuel is considered advantageous for ducted rocket applications due to its high energy density and dual-stage combustion process.Nonetheless,its performance is constrained by the formation of a protective boron oxide layer.In the current study,iron nanoparticles are incorporated into boron-based solid fuel to enhance boron's burning.Paraffin wax serves as the primary fuel and binder,while gaseous oxygen is used as an oxidizer.Four different solid fuel combinations were investigated in the experiment:pure paraffin wax,paraffin wax mixed with boron particles,and paraffin wax mixed with boron alongside 10%and 20%iron particles.The main effort of the research is to assess their combustion characteristics,focusing on regression rate and combustion efficiency.While the inclusion of 10%iron particles resulted in a decrease in the regression rate,it led to an improvement in combustion efficiency by reducing the residual active boron content in the condensed combustion product by~60%.Furthermore,it was observed that increasing the proportion of iron particles to 20%further enhanced combustion efficiency to approximately 4%.The entire assessment has been carried out using a lab-scale hybrid propellant ducted rocket motor configuration having an inlet duct on regenerative concept with the secondary combustor.In the present investigation oxygen is injected both in the primary and the secondary combustor,whereas in the existing actual/lab-scale ducted rockets,an energized air is introduced in the secondary combustor.It serves as an economical system for the preliminary investigation of solid fuel impregnated with boron particles.It is expected that the present study could prove valuable strategies for future applications of boron-based hybrid propellants in ducted rocket systems.
