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
Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interf...Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of sodium-potassium(NaK)alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the physical contact of the electrode-electrolyte interface.Additionally,the filling of SiO_(2) nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 hrs.The full cell coupled with Na_(3)V_(2)(PO_(4))_(2) cathodes had an initial discharge capacity of 106.8 mAh·g^(-1) with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1) even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.展开更多
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.
基金National Natural Science Foundation of China (52073253)。
文摘Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of sodium-potassium(NaK)alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the physical contact of the electrode-electrolyte interface.Additionally,the filling of SiO_(2) nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 hrs.The full cell coupled with Na_(3)V_(2)(PO_(4))_(2) cathodes had an initial discharge capacity of 106.8 mAh·g^(-1) with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1) even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.
