The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microsc...The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microscope) and XRD (X- ray Diffraction) techniques. Themechanical properties such as bending strength and fracture toughness, as well as their changes withadvancing crystallization were determined. The results show that the changes of the mechanicalproperties are correlated with the microstructures. The sample heated up to 810 deg C and soaked for4 h has smaller crystalline size and less volum fraction of fluorophlogopite, so it has higherbending strength (about 190 MPa), and higher crack toughness (about 2.63 MPa centre dot m^1/2).展开更多
针对高放废液硼硅酸盐玻璃固化体易析出辉石晶相的问题,本文采用P_(2)O_(5)部分替代硼硅酸盐基础玻璃配方中的MgO和CaO,研究了P_(2)O_(5)掺量(质量分数为0~8%)对玻璃固化体析晶和抗浸出性能的影响。结果表明,当P_(2)O_(5)掺量为0~3%时,...针对高放废液硼硅酸盐玻璃固化体易析出辉石晶相的问题,本文采用P_(2)O_(5)部分替代硼硅酸盐基础玻璃配方中的MgO和CaO,研究了P_(2)O_(5)掺量(质量分数为0~8%)对玻璃固化体析晶和抗浸出性能的影响。结果表明,当P_(2)O_(5)掺量为0~3%时,样品为无定形态,在850℃热处理6 h后,P_(2)O_(5)掺量为0~2%的样品主要析出辉石晶相,而P_(2)O_(5)掺量为3%的样品析出了少量硅酸钙晶相,辉石晶相基本消失;当P_(2)O_(5)掺量高于3%时,样品析出球形Na_(3)Ca_(6)(PO_(4))_(5)晶体,且析晶度随P_(2)O_(5)掺量的增加而升高。29 Si MAS NMR和^(11)B MAS NMR分析表明,随着P_(2)O_(5)掺量的增加,玻璃网络结构中Q^(3)、Q^(4)和BO_(3)结构单元含量逐渐增加。静态浸泡法(MCC-1)试验结果表明,样品的抗浸出性能随P_(2)O_(5)掺量的增加而逐渐提高,其中P_(2)O_(5)掺量为3%的样品浸泡28 d后,Si、B、Na和Cs元素的归一化浸出率分别为0.508、0.468、0.533、0.280 g/(m^(2)·d)。展开更多
A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,micros...A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,microstructures,and microwave dielectric properties were investigated.The results of x-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that a single phase of MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with a spinel structure was obtained at x≤0.12,whereas the second phase of MgTi_(2)O_(5)appeared when x>0.12.The cell parameters were obtained by XRD refinement.As the x values increased,the unit cell volume kept expanding.This phenomenon could be attributed to the partial substitution of(Li_(1/3)Ti_(2/3))^(3+)for Al^(3+).Results showed that(Li_(1/3)Ti_(2/3))^(3+)doping into MgAl_(2)O_(4)spinel ceramics effectively reduced the sintering temperature and improved the quality factor(Q_f)values.Good microwave dielectric properties were achieved for a sample at x=0.20 sintering at 1500℃in air for 4 h:dielectric constantε_(r)=8.78,temperature coefficient of resonant frequencyτ_(f)=-85 ppm/℃,and Q_(f)=62300 GHz.The Q_(f)value of the x=0.20 sample was about 2 times higher than that of pure MgAl_(2)O_(4)ceramics(31600 GHz).Thus,MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with excellent microwave dielectric properties can be applied to 5G communications.展开更多
The selection of the most suitable crystal structure for ions storage and the investigation of the corresponding reaction mechanism is still an ongoing challenge for the development of Mg-based batteries.In this artic...The selection of the most suitable crystal structure for ions storage and the investigation of the corresponding reaction mechanism is still an ongoing challenge for the development of Mg-based batteries.In this article,high flexible graphene network supporting different crystal structures of Nb2 O5(TTNb_(2)O_(5)@rGO and T-Nb_(2)O_(5)@rGO) are successfully synthesized by a spray-drying-assisted approach.The three-dimensional graphene framework provides high conductivity and avoids the aggregation of Nb2 O5 nanoparticles.When employed as electrode materials for energy storage applications,TT-Nb_(2)O_(5) delivers a higher discharge capacity of 129.5 mAh g^(-1), about twice that of T-Nb_(2)O_(5) for Mg-storage,whereas,T-Nb_(2)O_(5) delivers a much higher capacity(162 mAh g^(-1)) compared with TT-Nb_(2)O_(5)(129 mAh g^(-1)) for Li-storage.Detailed investigations reveal the Mg intercalation mechanism and lower Mg^(2+) migration barriers,faster Mg^(2+) diffusion kinetics of TT-Nb_(2)O_(5) as cathode material for Mg-storage,and the faster Li+ diffusion kinetics,shorter diffusion distance of T-Nb_(2)O_(5) as cathode material for Li-storage.Our work demonstrates that exploring the proper crystal structure of Nb2 O5 for different ions storage is necessary.展开更多
Transparent Ce:lutetium aluminum garnet(Ce:Lu_(3)A_(l5)O_(12),Ce:LuAG)ceramics have been regarded as potential scintillator materials due to their relatively high density and atomic number(Zeff).However,the current Ce...Transparent Ce:lutetium aluminum garnet(Ce:Lu_(3)A_(l5)O_(12),Ce:LuAG)ceramics have been regarded as potential scintillator materials due to their relatively high density and atomic number(Zeff).However,the current Ce:LuAG ceramics exhibit a light yield much lower than the expected theoretical value due to the inevitable presence of LuAl antisite defects at high sintering temperatures.This work demonstrates a low-temperature(1100℃)synthetic strategy for elaborating transparent LuAG–Al_(2)O_(3) nanoceramics through the crystallization of 72 mol%Al_(2)O_(3)–28 mol%Lu_(2)O_(3)(ALu28)bulk glass.The biphasic nanostructure composed of LuAG and Al_(2)O_(3) nanocrystals makes up the whole ceramic materials.Most of Al_(2)O_(3) is distributed among LuAG grains,and the rest is present inside the LuAG grains.Fully dense biphasic LuAG–Al_(2)O_(3) nanoceramics are highly transparent from the visible region to mid-infrared(MIR)region,and particularly the transmittance reaches 82%at 780 nm.Moreover,LuAl antisite defect-related centers are completely undetectable in X-ray excited luminescence(XEL)spectra of Ce:LuAG–Al_(2)O_(3) nanoceramics with 0.3–1.0 at%Ce.The light yield of 0.3 at%Ce:LuAG–Al_(2)O_(3) nanoceramics is estimated to be 20,000 ph/MeV with short 1μs shaping time,which is far superior to that of commercial Bi_(4)Ge_(3)O_(12)(BGO)single crystals.These results show that a low-temperature glass crystallization route provides an alternative approach for eliminating the antisite defects in LuAG-based ceramics,and is promising to produce garnet-based ceramic materials with excellent properties,thereby meeting the demands of advanced scintillation applications.展开更多
Ce doped Lu_(3)Al_(5)O_(12)(Ce:LuAG)transparent ceramics are considered as promising color converters for solid-state lighting because of their excellent luminous efficiency,high thermal quenching temperature,and good...Ce doped Lu_(3)Al_(5)O_(12)(Ce:LuAG)transparent ceramics are considered as promising color converters for solid-state lighting because of their excellent luminous efficiency,high thermal quenching temperature,and good thermal stability.However,Ce:LuAG ceramics mainly emit green light.The shortage of red light as well as the expensive price of Lu compounds are hindering their application for white lighting.In this work,transparent(Lu,Gd)_(3)Al_(5)O_(12)–Al_(2)O_(3)(LuGAG–Al_(2)O_(3))nanoceramics with different replacing contents of Gd^(3+)(10%–50%)were successfully elaborated via a glass-crystallization method.The obtained ceramics with full nanoscale grains are composed of the main LuGAG crystalline phase and secondary Al_(2)O_(3) phase,exhibiting eminent transparency of 81.0%@780 nm.After doping by Ce^(3+),the Ce:LuGAG–Al_(2)O_(3) nanoceramics show a significant red shift(510 nm→550 nm)and make up for the deficiency of red light component in the emission spectrum.The Ce:LuAG–Al_(2)O_(3) nanoceramics with 20%Gd^(3+)show high internal quantum efficiency(81.5%in internal quantum efficiency(IQE),96.7%of Ce:LuAG–Al_(2)O_(3) nanoceramics)and good thermal stability(only 9%loss in IQE at 150℃).When combined with blue LED chips(10 W),0.3%Ce:LuGAG–Al_(2)O_(3) nanoceramics with 20%Gd^(3+)successfully realize the high-quality warm white LED lighting with a color coordinate of(0.3566,0.435),a color temperature of 4347 K,CRI of 67.7,and a luminous efficiency of 175.8 lm·W^(−1).When the transparent 0.3%Ce:LuGAG–Al_(2)O_(3) nanoceramics are excited by blue laser(5 W·mm^(−2)),the emission peak position redshifts from 517 to 570 nm,the emitted light exhibits a continuous change from green light to yellow light,and then to orange-yellow light,and the maximum luminous efficiency is up to 234.49 lm·W^(−1)(20%Gd^(3+)).Taking into account the high quantum efficiency,good thermal stability,and excellent and adjustable luminous properties,the transparent Ce:LuGAG–Al_(2)O_(3) nanoceramics with different Gd^(3+)substitution contents in this paper are believed to be promising candidates for high-power white LED/LD lighting.展开更多
The morphology, size and phase of the material play a crucial role in its electrochemical performance.Herein, the nano-sized niobium pentoxide(Nb2O5) with different morphologies and phase structures are synthesized th...The morphology, size and phase of the material play a crucial role in its electrochemical performance.Herein, the nano-sized niobium pentoxide(Nb2O5) with different morphologies and phase structures are synthesized through a very simple thermal treatment method, including the pseudo hexagonal Nb2O5nanosheets and pseudo hexagonal Nb2O5nanoparticles, orthorhombic Nb2O5nanoparticles. The synthesized pseudohexagonal Nb2O5 nanosheets and orthorhombic Nb2O5nanoparticles exhibit better cycling and rate performance than the pseudohexagonal Nb2 O5 nanoparticles due to the different morphologies and phase structures. The T-Nb2O5-700 nanoparticles show the higher capacity(175 mAh/g) than that of TT-Nb2O5-500 nanosheets(127 mAh/g) and TT-Nb2O5-600 nanoparticles(39 mAh/g) at a current density of 50 mA/g and good rate performance with a capacity of 140 mAh/g at 1.0 A/g. The excellent rate capability and cycling stability of orthorhombic T-Nb2O5may be ascribed to the dominant contribution of pseudocapacitive effect. This material has the great potential as a practical high-rate anode material for lithium-ion batteries.展开更多
Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide p...Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide precursors typically comprise aggregated polycrystalline particles with defects and grain boundaries that reduce the water oxidation activity of the material.In the present work,well-dispersed Ta3N5 nanoparticulate single crystals were synthesized via a mild nitridation process using pure Ta metal nanopowder or Ta nanopowder mixed with NaCl.The resulting high-quality Ta3N5 nanoparticles,after loading with an oxygen evolution cocatalyst,exhibited impressively high photocatalytic performance during O_(2)evolution from a sacrificial AgNO3 solution,with an apparent quantum yield of 9.4%at 420 nm.Our findings suggest a new approach to the facile fabrication of nanostructured single-crystal photocatalysts for efficient solar water splitting,based on the use of metal nanopowders.展开更多
文摘The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microscope) and XRD (X- ray Diffraction) techniques. Themechanical properties such as bending strength and fracture toughness, as well as their changes withadvancing crystallization were determined. The results show that the changes of the mechanicalproperties are correlated with the microstructures. The sample heated up to 810 deg C and soaked for4 h has smaller crystalline size and less volum fraction of fluorophlogopite, so it has higherbending strength (about 190 MPa), and higher crack toughness (about 2.63 MPa centre dot m^1/2).
文摘针对高放废液硼硅酸盐玻璃固化体易析出辉石晶相的问题,本文采用P_(2)O_(5)部分替代硼硅酸盐基础玻璃配方中的MgO和CaO,研究了P_(2)O_(5)掺量(质量分数为0~8%)对玻璃固化体析晶和抗浸出性能的影响。结果表明,当P_(2)O_(5)掺量为0~3%时,样品为无定形态,在850℃热处理6 h后,P_(2)O_(5)掺量为0~2%的样品主要析出辉石晶相,而P_(2)O_(5)掺量为3%的样品析出了少量硅酸钙晶相,辉石晶相基本消失;当P_(2)O_(5)掺量高于3%时,样品析出球形Na_(3)Ca_(6)(PO_(4))_(5)晶体,且析晶度随P_(2)O_(5)掺量的增加而升高。29 Si MAS NMR和^(11)B MAS NMR分析表明,随着P_(2)O_(5)掺量的增加,玻璃网络结构中Q^(3)、Q^(4)和BO_(3)结构单元含量逐渐增加。静态浸泡法(MCC-1)试验结果表明,样品的抗浸出性能随P_(2)O_(5)掺量的增加而逐渐提高,其中P_(2)O_(5)掺量为3%的样品浸泡28 d后,Si、B、Na和Cs元素的归一化浸出率分别为0.508、0.468、0.533、0.280 g/(m^(2)·d)。
基金the Chengdu University of Technology(Grant No.KYQD201907728)。
文摘A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,microstructures,and microwave dielectric properties were investigated.The results of x-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that a single phase of MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with a spinel structure was obtained at x≤0.12,whereas the second phase of MgTi_(2)O_(5)appeared when x>0.12.The cell parameters were obtained by XRD refinement.As the x values increased,the unit cell volume kept expanding.This phenomenon could be attributed to the partial substitution of(Li_(1/3)Ti_(2/3))^(3+)for Al^(3+).Results showed that(Li_(1/3)Ti_(2/3))^(3+)doping into MgAl_(2)O_(4)spinel ceramics effectively reduced the sintering temperature and improved the quality factor(Q_f)values.Good microwave dielectric properties were achieved for a sample at x=0.20 sintering at 1500℃in air for 4 h:dielectric constantε_(r)=8.78,temperature coefficient of resonant frequencyτ_(f)=-85 ppm/℃,and Q_(f)=62300 GHz.The Q_(f)value of the x=0.20 sample was about 2 times higher than that of pure MgAl_(2)O_(4)ceramics(31600 GHz).Thus,MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with excellent microwave dielectric properties can be applied to 5G communications.
基金supported by the National Natural Science Foundation of China(51972259,51832004,51521001)the Fundamental Research Funds for the Central Universities(WUT:2020III043GX,2020III015GX)+2 种基金Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHT2020-003)the National Key Research and Development Program of China(2016YFA0202601)the Hubei Provincial Natural Science Foundation of China(2019CFB519)。
文摘The selection of the most suitable crystal structure for ions storage and the investigation of the corresponding reaction mechanism is still an ongoing challenge for the development of Mg-based batteries.In this article,high flexible graphene network supporting different crystal structures of Nb2 O5(TTNb_(2)O_(5)@rGO and T-Nb_(2)O_(5)@rGO) are successfully synthesized by a spray-drying-assisted approach.The three-dimensional graphene framework provides high conductivity and avoids the aggregation of Nb2 O5 nanoparticles.When employed as electrode materials for energy storage applications,TT-Nb_(2)O_(5) delivers a higher discharge capacity of 129.5 mAh g^(-1), about twice that of T-Nb_(2)O_(5) for Mg-storage,whereas,T-Nb_(2)O_(5) delivers a much higher capacity(162 mAh g^(-1)) compared with TT-Nb_(2)O_(5)(129 mAh g^(-1)) for Li-storage.Detailed investigations reveal the Mg intercalation mechanism and lower Mg^(2+) migration barriers,faster Mg^(2+) diffusion kinetics of TT-Nb_(2)O_(5) as cathode material for Mg-storage,and the faster Li+ diffusion kinetics,shorter diffusion distance of T-Nb_(2)O_(5) as cathode material for Li-storage.Our work demonstrates that exploring the proper crystal structure of Nb2 O5 for different ions storage is necessary.
基金supported by the National Natural Science Foundation of China (No.51972304)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park (No.Z221100006722022)+1 种基金the Project of Scientific Experiment on Chinese Manned Space Station,Chinese Academy of Sciences President’s International Fellowship Initiative for 2021 (No.2021VEA0012)the Fundamental Research Funds for the Central Universities.
文摘Transparent Ce:lutetium aluminum garnet(Ce:Lu_(3)A_(l5)O_(12),Ce:LuAG)ceramics have been regarded as potential scintillator materials due to their relatively high density and atomic number(Zeff).However,the current Ce:LuAG ceramics exhibit a light yield much lower than the expected theoretical value due to the inevitable presence of LuAl antisite defects at high sintering temperatures.This work demonstrates a low-temperature(1100℃)synthetic strategy for elaborating transparent LuAG–Al_(2)O_(3) nanoceramics through the crystallization of 72 mol%Al_(2)O_(3)–28 mol%Lu_(2)O_(3)(ALu28)bulk glass.The biphasic nanostructure composed of LuAG and Al_(2)O_(3) nanocrystals makes up the whole ceramic materials.Most of Al_(2)O_(3) is distributed among LuAG grains,and the rest is present inside the LuAG grains.Fully dense biphasic LuAG–Al_(2)O_(3) nanoceramics are highly transparent from the visible region to mid-infrared(MIR)region,and particularly the transmittance reaches 82%at 780 nm.Moreover,LuAl antisite defect-related centers are completely undetectable in X-ray excited luminescence(XEL)spectra of Ce:LuAG–Al_(2)O_(3) nanoceramics with 0.3–1.0 at%Ce.The light yield of 0.3 at%Ce:LuAG–Al_(2)O_(3) nanoceramics is estimated to be 20,000 ph/MeV with short 1μs shaping time,which is far superior to that of commercial Bi_(4)Ge_(3)O_(12)(BGO)single crystals.These results show that a low-temperature glass crystallization route provides an alternative approach for eliminating the antisite defects in LuAG-based ceramics,and is promising to produce garnet-based ceramic materials with excellent properties,thereby meeting the demands of advanced scintillation applications.
基金This work is financially supported by the National Natural Science Foundation of China(No.51972304)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100006722022)+1 种基金the Project of Scientific Experiment on Chinese Manned Space Station,Chinese Academy of Sciences President’s International Fellowship Initiative for 2021(No.2021VEA0012)the Fundamental Research Funds for the Central Universities.The project benefitted from the microscopy facilities of the Platform MACLE-CVL which was co-funded by the European Union and Centre-Val de Loire Region(FEDER).Declaration of competing interest。
文摘Ce doped Lu_(3)Al_(5)O_(12)(Ce:LuAG)transparent ceramics are considered as promising color converters for solid-state lighting because of their excellent luminous efficiency,high thermal quenching temperature,and good thermal stability.However,Ce:LuAG ceramics mainly emit green light.The shortage of red light as well as the expensive price of Lu compounds are hindering their application for white lighting.In this work,transparent(Lu,Gd)_(3)Al_(5)O_(12)–Al_(2)O_(3)(LuGAG–Al_(2)O_(3))nanoceramics with different replacing contents of Gd^(3+)(10%–50%)were successfully elaborated via a glass-crystallization method.The obtained ceramics with full nanoscale grains are composed of the main LuGAG crystalline phase and secondary Al_(2)O_(3) phase,exhibiting eminent transparency of 81.0%@780 nm.After doping by Ce^(3+),the Ce:LuGAG–Al_(2)O_(3) nanoceramics show a significant red shift(510 nm→550 nm)and make up for the deficiency of red light component in the emission spectrum.The Ce:LuAG–Al_(2)O_(3) nanoceramics with 20%Gd^(3+)show high internal quantum efficiency(81.5%in internal quantum efficiency(IQE),96.7%of Ce:LuAG–Al_(2)O_(3) nanoceramics)and good thermal stability(only 9%loss in IQE at 150℃).When combined with blue LED chips(10 W),0.3%Ce:LuGAG–Al_(2)O_(3) nanoceramics with 20%Gd^(3+)successfully realize the high-quality warm white LED lighting with a color coordinate of(0.3566,0.435),a color temperature of 4347 K,CRI of 67.7,and a luminous efficiency of 175.8 lm·W^(−1).When the transparent 0.3%Ce:LuGAG–Al_(2)O_(3) nanoceramics are excited by blue laser(5 W·mm^(−2)),the emission peak position redshifts from 517 to 570 nm,the emitted light exhibits a continuous change from green light to yellow light,and then to orange-yellow light,and the maximum luminous efficiency is up to 234.49 lm·W^(−1)(20%Gd^(3+)).Taking into account the high quantum efficiency,good thermal stability,and excellent and adjustable luminous properties,the transparent Ce:LuGAG–Al_(2)O_(3) nanoceramics with different Gd^(3+)substitution contents in this paper are believed to be promising candidates for high-power white LED/LD lighting.
基金supported by the National Natural Science Foundation of China(No.51302079)the Natural Science Foundation of Hunan Province(No.2017JJ1008)
文摘The morphology, size and phase of the material play a crucial role in its electrochemical performance.Herein, the nano-sized niobium pentoxide(Nb2O5) with different morphologies and phase structures are synthesized through a very simple thermal treatment method, including the pseudo hexagonal Nb2O5nanosheets and pseudo hexagonal Nb2O5nanoparticles, orthorhombic Nb2O5nanoparticles. The synthesized pseudohexagonal Nb2O5 nanosheets and orthorhombic Nb2O5nanoparticles exhibit better cycling and rate performance than the pseudohexagonal Nb2 O5 nanoparticles due to the different morphologies and phase structures. The T-Nb2O5-700 nanoparticles show the higher capacity(175 mAh/g) than that of TT-Nb2O5-500 nanosheets(127 mAh/g) and TT-Nb2O5-600 nanoparticles(39 mAh/g) at a current density of 50 mA/g and good rate performance with a capacity of 140 mAh/g at 1.0 A/g. The excellent rate capability and cycling stability of orthorhombic T-Nb2O5may be ascribed to the dominant contribution of pseudocapacitive effect. This material has the great potential as a practical high-rate anode material for lithium-ion batteries.
基金supported by the Artificial Photosynthesis Project of the New Energy and Industrial Technology Development Organization(NEDO).Part of this work was conducted at the Advanced Characterization Nanotechnology Platform of the University of Tokyo,supported by the“Nanotechnology Platform”of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan(No.JPMXP09A-19-UT-0023).
文摘Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide precursors typically comprise aggregated polycrystalline particles with defects and grain boundaries that reduce the water oxidation activity of the material.In the present work,well-dispersed Ta3N5 nanoparticulate single crystals were synthesized via a mild nitridation process using pure Ta metal nanopowder or Ta nanopowder mixed with NaCl.The resulting high-quality Ta3N5 nanoparticles,after loading with an oxygen evolution cocatalyst,exhibited impressively high photocatalytic performance during O_(2)evolution from a sacrificial AgNO3 solution,with an apparent quantum yield of 9.4%at 420 nm.Our findings suggest a new approach to the facile fabrication of nanostructured single-crystal photocatalysts for efficient solar water splitting,based on the use of metal nanopowders.
