For rechargeable aqueous zinc-ion batteries(ZIBs),the design of nanocomposites comprised of electrochemically active materials and carbon materials with novel structures has great prom-ise in addressing the issue of e...For rechargeable aqueous zinc-ion batteries(ZIBs),the design of nanocomposites comprised of electrochemically active materials and carbon materials with novel structures has great prom-ise in addressing the issue of electrical conductivity and structural stability in the electrode materials during electrochemical cycling.We report the production of a novel flexible electrode material,by anchoring MnO_(2) nanosheets on a B,N co-doped carbon nanotube ar-ray(BNCNTs)grown on carbon cloth(BNCNTs@MnO_(2)),which was fabricated by in-situ pyrolysis and hydrothermal growth.The generated BNCNTs were strongly bonded to the surface of the car-bon fibers in the carbon cloth which provides both excellent elec-tron transport and ion diffusion,and improves the stability and dur-ability of the cathode.Importantly,the BNCNTs offer more active sites for the hydrothermal growth of MnO_(2),ensuring a uniform dis-tribution.Electrochemical tests show that BNCNTs@MnO_(2) delivers a high specific capacity of 310.7 mAh g^(−1) at 0.1 A g^(−1),along with excellent rate capability and outstanding cycling stability,with a 79.7% capacity retention after 8000 cycles at 3 A g^(−1).展开更多
Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),...Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),x=1.0,2.0,3.0,4.0)was synthesized via solid-phase reaction of sodium citrate(NaCA)and pure CN powder in the Teflon-sealed autoclave under air conditions at 180℃.Surface area of Na/O-CN_(3.0) is measured to be 18.8 m^(2)/g,increasing by 60.7%compared to that of pure CN(11.7 m^(2)/g).Bandgap energy of Na/O-CN_(3.0) is determined to be 2.68 eV,marginally lower than that of pure CN(2.70 eV),thereby enhancing its capacity for sunlight absorption.Meanwhile,the incorporation of Na and O atoms into Na/O-CN_(x) is found to effectively reduce recombination rates of photogenerated electron-hole pairs.As a result,Na/O-CN_(x) samples exhibit markedly enhanced photocatalytic hydrogen evolution activity under visible light irradiation.Notably,the optimal Na/O-CN_(3.0) sample achieves a photocatalytic hydrogen production rate of 103.2μmol·g^(–1)·h^(–1),which is 8.2 times greater than that of pure CN(11.2μmol·g^(–1)·h^(–1)).Furthermore,a series of Na/O-CN_(x)-yO_(2)(y=0,20%,40%,60%,80%,100%)samples were prepared by modulating the oxygen content within reaction atmosphere.The catalytic performance evaluations reveal that the incorporation of both Na and O atoms in Na/O-CN_(3.0) enhances photocatalytic activity.This study also introduces novel methodologies for synthesis of metal atom-doped CN materials at lower temperature,highlighting the synergistic effect of Na and O atoms in photocatalytic hydrogen production of Na/O-CN_(x) samples.展开更多
随着特高压输电技术的快速发展和大容量电力传输需求的不断增加,绝缘纸在极端环境下的电气性能、机械强度及热稳定性面临着更为严峻的挑战。该文提出纳米SiO_(2)粒子掺杂与等离子体氟化协同改性策略,系统研究协同改性前后绝缘纸的电气...随着特高压输电技术的快速发展和大容量电力传输需求的不断增加,绝缘纸在极端环境下的电气性能、机械强度及热稳定性面临着更为严峻的挑战。该文提出纳米SiO_(2)粒子掺杂与等离子体氟化协同改性策略,系统研究协同改性前后绝缘纸的电气性能、机械性能、疏水性能及热老化性能的演变规律,通过扫描电子显微镜(scanning electron microscope,SEM)和能量色散X射线光谱仪(energy dispersive spectrometer,EDS)表征氟化处理后绝缘纸表面形貌与元素分布变化。基于分子动力学模拟,揭示纳米粒子掺杂和含氟基团介质的协同增强机制。结果表明:纳米SiO_(2)粒子掺杂协同等离子体氟化改性可有效限制载流子的运动,显著提升了绝缘纸的绝缘性能。与未改性相比,绝缘纸的击穿场强和体积电阻率分别提高109.2%和134.9%。协同改性处理后,绝缘纸表面接枝了大量含氟基团,显著提升其表面疏水性;同时,含氟基团与纳米SiO_(2)间形成的氢键强化了纳米SiO_(2)与绝缘纸的桥接作用,进而可有效提升绝缘纸的热老化性能。展开更多
基金financial support from projects funded by the National Natural Science Foundation of China(52172038,22179017)the National Key Research and Development Program of China(2022YFB4101600,2022YFB4101601)。
文摘For rechargeable aqueous zinc-ion batteries(ZIBs),the design of nanocomposites comprised of electrochemically active materials and carbon materials with novel structures has great prom-ise in addressing the issue of electrical conductivity and structural stability in the electrode materials during electrochemical cycling.We report the production of a novel flexible electrode material,by anchoring MnO_(2) nanosheets on a B,N co-doped carbon nanotube ar-ray(BNCNTs)grown on carbon cloth(BNCNTs@MnO_(2)),which was fabricated by in-situ pyrolysis and hydrothermal growth.The generated BNCNTs were strongly bonded to the surface of the car-bon fibers in the carbon cloth which provides both excellent elec-tron transport and ion diffusion,and improves the stability and dur-ability of the cathode.Importantly,the BNCNTs offer more active sites for the hydrothermal growth of MnO_(2),ensuring a uniform dis-tribution.Electrochemical tests show that BNCNTs@MnO_(2) delivers a high specific capacity of 310.7 mAh g^(−1) at 0.1 A g^(−1),along with excellent rate capability and outstanding cycling stability,with a 79.7% capacity retention after 8000 cycles at 3 A g^(−1).
基金National Natural Science Foundation of China(21806023)Natural Science Foundation of Hunan Province(2021JJ40199)+2 种基金Education Department Foundation of Hunan Province(20C0813)Hunan University of Science and Technology Fundamental Research FundsPostgraduate Scientific Research Innovation Project of Hunan Province(CX20240877)。
文摘Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),x=1.0,2.0,3.0,4.0)was synthesized via solid-phase reaction of sodium citrate(NaCA)and pure CN powder in the Teflon-sealed autoclave under air conditions at 180℃.Surface area of Na/O-CN_(3.0) is measured to be 18.8 m^(2)/g,increasing by 60.7%compared to that of pure CN(11.7 m^(2)/g).Bandgap energy of Na/O-CN_(3.0) is determined to be 2.68 eV,marginally lower than that of pure CN(2.70 eV),thereby enhancing its capacity for sunlight absorption.Meanwhile,the incorporation of Na and O atoms into Na/O-CN_(x) is found to effectively reduce recombination rates of photogenerated electron-hole pairs.As a result,Na/O-CN_(x) samples exhibit markedly enhanced photocatalytic hydrogen evolution activity under visible light irradiation.Notably,the optimal Na/O-CN_(3.0) sample achieves a photocatalytic hydrogen production rate of 103.2μmol·g^(–1)·h^(–1),which is 8.2 times greater than that of pure CN(11.2μmol·g^(–1)·h^(–1)).Furthermore,a series of Na/O-CN_(x)-yO_(2)(y=0,20%,40%,60%,80%,100%)samples were prepared by modulating the oxygen content within reaction atmosphere.The catalytic performance evaluations reveal that the incorporation of both Na and O atoms in Na/O-CN_(3.0) enhances photocatalytic activity.This study also introduces novel methodologies for synthesis of metal atom-doped CN materials at lower temperature,highlighting the synergistic effect of Na and O atoms in photocatalytic hydrogen production of Na/O-CN_(x) samples.
文摘随着特高压输电技术的快速发展和大容量电力传输需求的不断增加,绝缘纸在极端环境下的电气性能、机械强度及热稳定性面临着更为严峻的挑战。该文提出纳米SiO_(2)粒子掺杂与等离子体氟化协同改性策略,系统研究协同改性前后绝缘纸的电气性能、机械性能、疏水性能及热老化性能的演变规律,通过扫描电子显微镜(scanning electron microscope,SEM)和能量色散X射线光谱仪(energy dispersive spectrometer,EDS)表征氟化处理后绝缘纸表面形貌与元素分布变化。基于分子动力学模拟,揭示纳米粒子掺杂和含氟基团介质的协同增强机制。结果表明:纳米SiO_(2)粒子掺杂协同等离子体氟化改性可有效限制载流子的运动,显著提升了绝缘纸的绝缘性能。与未改性相比,绝缘纸的击穿场强和体积电阻率分别提高109.2%和134.9%。协同改性处理后,绝缘纸表面接枝了大量含氟基团,显著提升其表面疏水性;同时,含氟基团与纳米SiO_(2)间形成的氢键强化了纳米SiO_(2)与绝缘纸的桥接作用,进而可有效提升绝缘纸的热老化性能。
