The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties o...The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties of various glycol dimethyl ethers are screened,and diglyme(G2)is selected as the sole solvent for the electrolyte.Lithium bis(fluorosulfonyl)imide(LiFSI),a highly dissociative salt,is used as the primary salt;while lithium nitrate(LiNO_(3))and lithium difluorophosphate(LiDFP),which have small ionic sizes and strong binding energies,are added as secondary salts.The resulting electrolyte can modulate the electric double layer structure by NO_(3)^(-) and DFP^(-) on the cathode side,leading to an increased Liþconcentration that is originally repelled by the cathode.Additionally,the oxidation stability of the electrolyte is improved and the formed electrode-electrolyte interphase is more uniform and stable,thereby enhancing the electrochemical performance of the cells.As a result,cells assembled with a total of 1 M ternary lithium salts in G2 solvent can operate at high voltage of 4.4 V.The LijjNCM811 cells maintain 80.2%capacity retention after 270 cycles at room temperature,with an average Coulombic efficiency of 99.5%,and exhibit 88.4%capacity retention after 200 cycles at -30℃.展开更多
The sluggish reaction kinetics of the oxygen evolution reaction(OER)and methanol oxidation reaction(MOR)remain obstacles to the commercial promotion of water splitting and direct methanol fuel cells.Considering the vi...The sluggish reaction kinetics of the oxygen evolution reaction(OER)and methanol oxidation reaction(MOR)remain obstacles to the commercial promotion of water splitting and direct methanol fuel cells.Considering the vital role of noble metals in electrocatalytic activity,this work focuses on the rational synthesis of Ni-noble metal composite nanocatalysts for overcoming the drawbacks of high cost and susceptible oxidized surfaces of noble metals.The inherent catalytic activity is improved by the altered electronic structure and effective active sites of the catalyst induced by the size effect of noble metal clusters.In particular,a series of Ni-noble metal nanocomposites are successfully synthesized by partially introducing noble metal into Ni with porous interfacial defects derived from Ni-Al layered double hydroxide(LDH).The Ni_(10)Pd_(1)nanocomposite exhibits high OER catalytic activity with an overpotential of 0.279 V at 10 m A/cm^(2),surpassing Ni_(10)Ag_(1)and Ni_(10)Au_(1)counterparts.Furthermore,the average diameter of Pd clusters gradually increases from 5.57 nm to 44.44 nm with the increased proportion of doped Pd,leading to the passivation of catalytic activity due to the exacerbated surface oxidation of Pd in the form of Pd^(2+).After optimization,Ni_(10)Pd_(1)delivers significantly enhanced OER and MOR electroactivities and long-term stability compared to that of Ni_(2)Pd_(1),Ni_(1)Pd_(1)and Ni_(1)Pd_(2),which is conducive to the effective utilization of Pd and alleviation of surface oxidation.展开更多
During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impr...During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impression making of the prepared finish lines on the abutment teeth.To optimise long-term outcomes for the fixed restoration,gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment.Accurate marginal positioning of the restoration along the prepared finish line of the abutment is essential for therapeutic,preventive,and aesthetic purposes.展开更多
This study investigates the crystal structure,microstructure,electronic,thermal transport properties,and thermoelectric performance ofα-MgAgSb synthesized through various ball milling techniques.Variations in synthes...This study investigates the crystal structure,microstructure,electronic,thermal transport properties,and thermoelectric performance ofα-MgAgSb synthesized through various ball milling techniques.Variations in synthesis methods can significantly impact thermoelectric performance.Our findings indicate that impurity phases,particularly the secondary phase Ag_(3)Sb,hinder grain growth and decrease carrier mobility.By systematically adjusting milling conditions,the increased grain size resulting from the suppression of impurity formation improves charge carrier mobility and enhances the power factor.Low-temperature resistivity analysis reveals distinct scattering mechanisms influenced by impurity levels.α-MgAgSb with a tiny content of Sb primarily exhibits electron-electron scattering,whereas higher impurity levels introduce both electron-electron and electron-phonon scattering.Additionally,thermal conductivity analysis using three Effective Medium Theory(EMT)methods shows that the distribution of Ag_(3)Sb increases interfacial resistance.The maximum zT value of 1.36 was achieved in a compound with anα-MgAgSb to Sb ratio of 99%:1%.展开更多
Rechargeable magnesium batteries(RMBs)are a cutting-edge energy storage solution,with several advantages over the state-of-art lithiumion batteries(LIBs).The use of magnesium(Mg)metal as an anode material provides a m...Rechargeable magnesium batteries(RMBs)are a cutting-edge energy storage solution,with several advantages over the state-of-art lithiumion batteries(LIBs).The use of magnesium(Mg)metal as an anode material provides a much higher gravimetric capacity compared to graphite,which is currently used as the anode material in LIBs.Despite the significant advances in electrolyte,the development of cathode material is limited to materials that operate at low average discharge voltage(<1.0 V vs.Mg/Mg^(2+)),and developing high voltage cathodes remains challenging.Only a few materials have been shown to intercalate Mg^(2+)ions reversibly at high voltage.This review focuses on the structural aspects of cathode material that can operate at high voltage,including the Mg^(2+)intercalation mechanism in relation to its electrochemical properties.The materials are categorized into transition metal oxides and polyanions and subcategorized by the intrinsic Mg^(2+)diffusion path.This review also provides insights into the future development of each material,aiming to stimulate and guide researchers working in this field towards further advancements in high voltage cathodes.展开更多
This review focuses on the significant impact of heteroatom doping in enhancing the electronic properties and electrochemical performance of carbon materials for supercapacitors(SCs).Incorporating heteroatoms such as ...This review focuses on the significant impact of heteroatom doping in enhancing the electronic properties and electrochemical performance of carbon materials for supercapacitors(SCs).Incorporating heteroatoms such as nitrogen,sulfur,phosphorus,fluorine,and boron modifies the carbon structure,creates defects and increases active sites,which improves electronic conductivity,ion accessibility,and surface wettability and reduces ion diffusion barriers.Additionally,certain heteroatoms can participate in electrochemical reactions,further enhancing SC performance.Although research in this area is still emerging,a deeper understanding of the mechanisms behind single and multi-doping systems is essential for developing next-generation materials.Future strategies for improving heteroatom-doped carbon materials include increasing heteroatom content to enhance specific capacitance,selecting suitable heteroatoms to expand the potential window and improve energy density,utilizing advanced in situ characterization techniques,and exploring the use of these materials in cost-effective SCs.The potential of heteroatom-doped carbon materials for SCs is promising,with their ability to improve energy density,power density,and cycling stability,making them competitive with other energy storage technologies.These advancements will be key to broadening their practical applications,including electric vehicles,portable electronics,and grid energy storage,and will contribute to more efficient,long-lasting,and environmentally friendly energy storage solutions.展开更多
Solar-driven hydrogen peroxide(H_(2)O_(2))production offers a sustainable and environmentally friendly alternative to the traditional anthraquinone oxidation method.Conjugated polymers(CPs)are emerging as promising ph...Solar-driven hydrogen peroxide(H_(2)O_(2))production offers a sustainable and environmentally friendly alternative to the traditional anthraquinone oxidation method.Conjugated polymers(CPs)are emerging as promising photocatalysts for H_(2)O_(2)production due to their unique electronic,optical properties,and tunable structures.However,the high exciton binding energy of CPs hinders efficient exciton dissociation and charge separation,limiting their photocatalytic performance.In this work,we synthesized scandium(Sc)atoms decorated CPs with enhanced ordered stacking and crystallinity by introducing benzaldehyde as an end-capping reagent.The strong interaction between charged Sc atoms and electrons facilitates exciton dissociation and improves charge transfer capability.Furthermore,the Lewis acidic nature of Sc atoms promotes oxygen adsorption and enhances the stabilization of superoxide anion intermediate(·O_(2)^(-)).As a result,the as-synthesized photocatalysts exhibit a high H_(2)O_(2)production rate of 18μmol h^(-1)in pure water,which is three times that of pristine CPs,This work provides valuable insights into the design of organic polymer photocatalysts for various photocatalytic reactions.展开更多
Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal s...Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.展开更多
介绍了外推法技术,在此基础上提出一种基于几何光学的吸波材料影响评估方法.该方法可以在数字滤波后有效模拟并引入反射信号,通过比较两次外推后的数据,得到对增益测量的影响评估结果.在中国计量科学研究院(National Institute of Metro...介绍了外推法技术,在此基础上提出一种基于几何光学的吸波材料影响评估方法.该方法可以在数字滤波后有效模拟并引入反射信号,通过比较两次外推后的数据,得到对增益测量的影响评估结果.在中国计量科学研究院(National Institute of Metrology,NIM)的外推法装置中进行实验验证,结果表明:该方法可以有效模拟吸波材料的影响,并给出由吸波材料引入的增益测量不确定度分量.该方法目前已应用到NIM和英国国家物理研究院(National Physical Laboratory,NPL)的外推法测量结果评定中,不仅对于外推法,对于在暗室中进行的其他天线测量结果的评估也具有很好的参考价值.展开更多
Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen...Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen evolution reaction(OER)due to their layered structure combined with versatile com-positions.Furthermore,reducing the thickness of platelet LDH crystals to nanometer or even molecular scale via cleavage or delamination provides an important clue to enhance the activity.In this review,recent progresses on rational design of LDH nanosheets are reviewed,including direct synthesis via traditional coprecipitation,homogeneous precipitation,and newly developed topochemical oxidation as well as chemical exfoliation of parent LDH crystals.In addition,diverse strategies are introduced to modulate their electrochemical activity by tuning the composition of host metal cations and intercalated counter-anions,and incorporating dopants,cavi-ties,and single atoms.In particular,hybridizing LDHs with conductive components or in situ growing them on conductive substrates to produce freestanding electrodes can further enhance their intrinsic catalytic activity.A brief discussion on future research directions and prospects is also summarized.展开更多
Boron nitride(BN) nanostructures with complementary functions to their carbon counterparts are one of the most intriguing nanomaterials.Here we devote a compact review on the syntheses of BN nanomaterials:typical zero...Boron nitride(BN) nanostructures with complementary functions to their carbon counterparts are one of the most intriguing nanomaterials.Here we devote a compact review on the syntheses of BN nanomaterials:typical zero-dimensional(OD) fullerenes and nanoparticles,one-dimensional(1D) nanotubes and nanoribbons,two-dimensional(2D) nanosheets as well as three-dimensional(3D) nanoporous BN.Combining low-dimensional quantum confinement and surface effects with unique physical and chemical properties of BN,e.g.excellent electric insulation,wide band gap,and high chemical and thermal stability,BN nanomaterials have drawn particular attention in a variety of potential applications,e.g.luminescence,functional composites,hydrogen accumulators,and advanced insulators,which are also reviewed.展开更多
We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged stat...We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged state of graphene and/or by introducing an external electric field arising from tourmaline.A simple two‐step hydrothermal method was used to synthesize G/T/TiO2composites and poly(diallyldimethylammonium chloride)‐G/T/TiO2composites.In the photocatalytic degradation of2‐propanol(IPA),the catalytic activity of the composite containing negatively charged graphene was higher than of the composite containing positively charged graphene.The highest acetone evolution rate(223?mol/h)was achieved using the ternary composite with the optimum composition,i.e.,G0.5/T5/TiO2(0.5wt%graphene and5wt%tourmaline).The involvement of tourmaline and graphene in the composite is believed to facilitate the separation and transportation of electrons and holes photogenerated in TiO2.This synergetic effect could account for the enhanced photocatalytic activity of the G/T/TiO2composite.A mechanistic study indicated that O2??radicals and holes were the main reactive oxygen species in photocatalytic degradation of IPA.展开更多
文摘The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties of various glycol dimethyl ethers are screened,and diglyme(G2)is selected as the sole solvent for the electrolyte.Lithium bis(fluorosulfonyl)imide(LiFSI),a highly dissociative salt,is used as the primary salt;while lithium nitrate(LiNO_(3))and lithium difluorophosphate(LiDFP),which have small ionic sizes and strong binding energies,are added as secondary salts.The resulting electrolyte can modulate the electric double layer structure by NO_(3)^(-) and DFP^(-) on the cathode side,leading to an increased Liþconcentration that is originally repelled by the cathode.Additionally,the oxidation stability of the electrolyte is improved and the formed electrode-electrolyte interphase is more uniform and stable,thereby enhancing the electrochemical performance of the cells.As a result,cells assembled with a total of 1 M ternary lithium salts in G2 solvent can operate at high voltage of 4.4 V.The LijjNCM811 cells maintain 80.2%capacity retention after 270 cycles at room temperature,with an average Coulombic efficiency of 99.5%,and exhibit 88.4%capacity retention after 200 cycles at -30℃.
基金support by the National Natural Science Foundation of China(Nos.U20A20123,51874357,22379166)Natural Science Foundation for Distinguished Young Scholars of Hunan Province(No.2022JJ10089)。
文摘The sluggish reaction kinetics of the oxygen evolution reaction(OER)and methanol oxidation reaction(MOR)remain obstacles to the commercial promotion of water splitting and direct methanol fuel cells.Considering the vital role of noble metals in electrocatalytic activity,this work focuses on the rational synthesis of Ni-noble metal composite nanocatalysts for overcoming the drawbacks of high cost and susceptible oxidized surfaces of noble metals.The inherent catalytic activity is improved by the altered electronic structure and effective active sites of the catalyst induced by the size effect of noble metal clusters.In particular,a series of Ni-noble metal nanocomposites are successfully synthesized by partially introducing noble metal into Ni with porous interfacial defects derived from Ni-Al layered double hydroxide(LDH).The Ni_(10)Pd_(1)nanocomposite exhibits high OER catalytic activity with an overpotential of 0.279 V at 10 m A/cm^(2),surpassing Ni_(10)Ag_(1)and Ni_(10)Au_(1)counterparts.Furthermore,the average diameter of Pd clusters gradually increases from 5.57 nm to 44.44 nm with the increased proportion of doped Pd,leading to the passivation of catalytic activity due to the exacerbated surface oxidation of Pd in the form of Pd^(2+).After optimization,Ni_(10)Pd_(1)delivers significantly enhanced OER and MOR electroactivities and long-term stability compared to that of Ni_(2)Pd_(1),Ni_(1)Pd_(1)and Ni_(1)Pd_(2),which is conducive to the effective utilization of Pd and alleviation of surface oxidation.
文摘During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impression making of the prepared finish lines on the abutment teeth.To optimise long-term outcomes for the fixed restoration,gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment.Accurate marginal positioning of the restoration along the prepared finish line of the abutment is essential for therapeutic,preventive,and aesthetic purposes.
基金financially supported by JST Mirai Program(No.JPMJMI19A1).
文摘This study investigates the crystal structure,microstructure,electronic,thermal transport properties,and thermoelectric performance ofα-MgAgSb synthesized through various ball milling techniques.Variations in synthesis methods can significantly impact thermoelectric performance.Our findings indicate that impurity phases,particularly the secondary phase Ag_(3)Sb,hinder grain growth and decrease carrier mobility.By systematically adjusting milling conditions,the increased grain size resulting from the suppression of impurity formation improves charge carrier mobility and enhances the power factor.Low-temperature resistivity analysis reveals distinct scattering mechanisms influenced by impurity levels.α-MgAgSb with a tiny content of Sb primarily exhibits electron-electron scattering,whereas higher impurity levels introduce both electron-electron and electron-phonon scattering.Additionally,thermal conductivity analysis using three Effective Medium Theory(EMT)methods shows that the distribution of Ag_(3)Sb increases interfacial resistance.The maximum zT value of 1.36 was achieved in a compound with anα-MgAgSb to Sb ratio of 99%:1%.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS-2024-00446825)by the Technology Innovation Program(RS-2024-00418815)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘Rechargeable magnesium batteries(RMBs)are a cutting-edge energy storage solution,with several advantages over the state-of-art lithiumion batteries(LIBs).The use of magnesium(Mg)metal as an anode material provides a much higher gravimetric capacity compared to graphite,which is currently used as the anode material in LIBs.Despite the significant advances in electrolyte,the development of cathode material is limited to materials that operate at low average discharge voltage(<1.0 V vs.Mg/Mg^(2+)),and developing high voltage cathodes remains challenging.Only a few materials have been shown to intercalate Mg^(2+)ions reversibly at high voltage.This review focuses on the structural aspects of cathode material that can operate at high voltage,including the Mg^(2+)intercalation mechanism in relation to its electrochemical properties.The materials are categorized into transition metal oxides and polyanions and subcategorized by the intrinsic Mg^(2+)diffusion path.This review also provides insights into the future development of each material,aiming to stimulate and guide researchers working in this field towards further advancements in high voltage cathodes.
基金supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22F22368,JP20H00392,and JP23H05459.
文摘This review focuses on the significant impact of heteroatom doping in enhancing the electronic properties and electrochemical performance of carbon materials for supercapacitors(SCs).Incorporating heteroatoms such as nitrogen,sulfur,phosphorus,fluorine,and boron modifies the carbon structure,creates defects and increases active sites,which improves electronic conductivity,ion accessibility,and surface wettability and reduces ion diffusion barriers.Additionally,certain heteroatoms can participate in electrochemical reactions,further enhancing SC performance.Although research in this area is still emerging,a deeper understanding of the mechanisms behind single and multi-doping systems is essential for developing next-generation materials.Future strategies for improving heteroatom-doped carbon materials include increasing heteroatom content to enhance specific capacitance,selecting suitable heteroatoms to expand the potential window and improve energy density,utilizing advanced in situ characterization techniques,and exploring the use of these materials in cost-effective SCs.The potential of heteroatom-doped carbon materials for SCs is promising,with their ability to improve energy density,power density,and cycling stability,making them competitive with other energy storage technologies.These advancements will be key to broadening their practical applications,including electric vehicles,portable electronics,and grid energy storage,and will contribute to more efficient,long-lasting,and environmentally friendly energy storage solutions.
基金supported by the Natural Science Foundation of China(22408278,22275139,21971190,U21A2077)the Key Project of Natural Science Foundation of Tianjin City(Contract No.22JCZDJC00510)Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University),Ministry of Education。
文摘Solar-driven hydrogen peroxide(H_(2)O_(2))production offers a sustainable and environmentally friendly alternative to the traditional anthraquinone oxidation method.Conjugated polymers(CPs)are emerging as promising photocatalysts for H_(2)O_(2)production due to their unique electronic,optical properties,and tunable structures.However,the high exciton binding energy of CPs hinders efficient exciton dissociation and charge separation,limiting their photocatalytic performance.In this work,we synthesized scandium(Sc)atoms decorated CPs with enhanced ordered stacking and crystallinity by introducing benzaldehyde as an end-capping reagent.The strong interaction between charged Sc atoms and electrons facilitates exciton dissociation and improves charge transfer capability.Furthermore,the Lewis acidic nature of Sc atoms promotes oxygen adsorption and enhances the stabilization of superoxide anion intermediate(·O_(2)^(-)).As a result,the as-synthesized photocatalysts exhibit a high H_(2)O_(2)production rate of 18μmol h^(-1)in pure water,which is three times that of pristine CPs,This work provides valuable insights into the design of organic polymer photocatalysts for various photocatalytic reactions.
基金financial support from the National Natural Science Foundation of China(No.22072183)the Natural Science Foundation of Hunan Province,China(No.2022JJ30690)supported in part by the High Performance Computing Center of Central South University。
文摘Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.
文摘介绍了外推法技术,在此基础上提出一种基于几何光学的吸波材料影响评估方法.该方法可以在数字滤波后有效模拟并引入反射信号,通过比较两次外推后的数据,得到对增益测量的影响评估结果.在中国计量科学研究院(National Institute of Metrology,NIM)的外推法装置中进行实验验证,结果表明:该方法可以有效模拟吸波材料的影响,并给出由吸波材料引入的增益测量不确定度分量.该方法目前已应用到NIM和英国国家物理研究院(National Physical Laboratory,NPL)的外推法测量结果评定中,不仅对于外推法,对于在暗室中进行的其他天线测量结果的评估也具有很好的参考价值.
基金supported in part by the WPIMANA,Ministry of Education,Culture,Sports,Science and TechnologyCREST of the Japan Science and Technology Agency(JST)(Grant No.JPMJCR17N1)the support from JSPS KAKENNHI grant 15H02004 and 18H03869.
文摘Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen evolution reaction(OER)due to their layered structure combined with versatile com-positions.Furthermore,reducing the thickness of platelet LDH crystals to nanometer or even molecular scale via cleavage or delamination provides an important clue to enhance the activity.In this review,recent progresses on rational design of LDH nanosheets are reviewed,including direct synthesis via traditional coprecipitation,homogeneous precipitation,and newly developed topochemical oxidation as well as chemical exfoliation of parent LDH crystals.In addition,diverse strategies are introduced to modulate their electrochemical activity by tuning the composition of host metal cations and intercalated counter-anions,and incorporating dopants,cavi-ties,and single atoms.In particular,hybridizing LDHs with conductive components or in situ growing them on conductive substrates to produce freestanding electrodes can further enhance their intrinsic catalytic activity.A brief discussion on future research directions and prospects is also summarized.
基金financial support of International Center for Young Scientists(ICYS)World Premier International Center for Materials Nanoarchitectonics(WPI-MANA) in National Institute for Materials Science(NIMS)financial support from KAKENHI project(Grant-in-Aid for Young Scientists,26820322) of Japan Society for the Promotion of Science(JSPS)
文摘Boron nitride(BN) nanostructures with complementary functions to their carbon counterparts are one of the most intriguing nanomaterials.Here we devote a compact review on the syntheses of BN nanomaterials:typical zero-dimensional(OD) fullerenes and nanoparticles,one-dimensional(1D) nanotubes and nanoribbons,two-dimensional(2D) nanosheets as well as three-dimensional(3D) nanoporous BN.Combining low-dimensional quantum confinement and surface effects with unique physical and chemical properties of BN,e.g.excellent electric insulation,wide band gap,and high chemical and thermal stability,BN nanomaterials have drawn particular attention in a variety of potential applications,e.g.luminescence,functional composites,hydrogen accumulators,and advanced insulators,which are also reviewed.
基金supported by the National Basic Research Program of China (973 Program,2014CB239300)the National Natural Science Foundation of China (51572191)the Natural Science Foundation of Tianjin (13JCYBJC16600)~~
文摘We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged state of graphene and/or by introducing an external electric field arising from tourmaline.A simple two‐step hydrothermal method was used to synthesize G/T/TiO2composites and poly(diallyldimethylammonium chloride)‐G/T/TiO2composites.In the photocatalytic degradation of2‐propanol(IPA),the catalytic activity of the composite containing negatively charged graphene was higher than of the composite containing positively charged graphene.The highest acetone evolution rate(223?mol/h)was achieved using the ternary composite with the optimum composition,i.e.,G0.5/T5/TiO2(0.5wt%graphene and5wt%tourmaline).The involvement of tourmaline and graphene in the composite is believed to facilitate the separation and transportation of electrons and holes photogenerated in TiO2.This synergetic effect could account for the enhanced photocatalytic activity of the G/T/TiO2composite.A mechanistic study indicated that O2??radicals and holes were the main reactive oxygen species in photocatalytic degradation of IPA.
