Y-doped Li3V2（PO4）3 cathode materials were prepared by a carbothermal reduction（CTR） process.The properties of the Y-doped Li3V2（PO4）3 were investigated by X-ray diffraction（XRD） and electrochemical measuremen...Y-doped Li3V2（PO4）3 cathode materials were prepared by a carbothermal reduction（CTR） process.The properties of the Y-doped Li3V2（PO4）3 were investigated by X-ray diffraction（XRD） and electrochemical measurements.XRD studies showed that the Y-doped Li3V2（PO4）3 had the same monoclinic structure as the undoped Li3V2（PO4）3.The Y-doped Li3V2（PO4）3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram（CV）, and electrochemical impedance spectra（EIS）.The optimal doping content of Y was x=0.03 in Li3V2-xYx（PO4）3 system.The Y-doped Li3V2（PO4）3 samples showed a better cyclic ability.The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Y-doping.The improved electrochemical perormances of the Y-doped Li3V2（PO4）3 cathode materials were attributed to the addition of Y3＋ ion by stabilizing the monoclinic structure.展开更多
Y-doped LiVPO4F cathode materials were prepared by a carbothermal reduction（CTR） process. The properties of the Y-doped LiVPOaF samples were investigated by X-ray diffraction （XRD） and electrochemical measurements...Y-doped LiVPO4F cathode materials were prepared by a carbothermal reduction（CTR） process. The properties of the Y-doped LiVPOaF samples were investigated by X-ray diffraction （XRD） and electrochemical measurements. XRD studies show that the Y-doped LiVPOaF samples have the same triclinic structure as the undoped LiVPO4F. The Li extraction/insertion performances of Y-doped LiVPO4F samples were investigated through charge/discharge, cyclic voltammogram （CV） , and electrochemical impedance spectra（EIS）. The optimal doping content of Y is x=0.04 in LiYxV1-xPO4F system. The Y-doped LiVPO4F samples show a better cyclic ability. The electrode reaction reversibility is enhanced, and the charge transfer resistance is decreased through the Y-doping. The improved electrochemical performances of the Y-doped LiVF＇OaF cathode materials are atlributed to the addidon of Y^3＋ ion by stabilizing the Iriclinic structure.展开更多
Cr-doped Li3V2（PO4）3 cathode materials Li3V2-xCr（PO4）3 were prepared by a carbothermal reduction（CTR） process. The properties of the Cr-doped Li3V2（PO4）3 were investigated by X-ray diffraction （XRD）, scannin...Cr-doped Li3V2（PO4）3 cathode materials Li3V2-xCr（PO4）3 were prepared by a carbothermal reduction（CTR） process. The properties of the Cr-doped Li3V2（PO4）3 were investigated by X-ray diffraction （XRD）, scanning electron microscopic （SEM）, and electrochemical measurements Results show that the Cr-doped Li3V2（PO4）3 has the same monoclinic structure as the undoped Li3V2（PO4）3, and the particle size of Cr-doped Li3V2（PO4）3 is smaller than that of the undoped Li3V2（PO4）3 and the smallest particle size is only about 1 1μm. The Cr-doped Li3V2（PO4）3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram （CV）, and electrochemical impedance spectra（EIS）. The optimal doping content of Cr was that x=0.04 in the Li3V2-xCrx（PO4）3 samples to achieve high discharge capacity and good cyclic stability. The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Cr-doping. The improved electrochemical performances of the Cr-doped Li3V2（PO4）3 cathode materials are attributed to the addition of Cr^3＋ ion by stabilizing the monoclinic structure.展开更多
Li3V2(PO4)3 cathode material was prepared by a carbon-thermal reduction (CTR) process. V2O5, LiOH-H2O, NH4H2PO4 and C were used as starting materials to synthesize Li3V2(PO4)3 by sintering the mixture at 800℃for 24 h...Li3V2(PO4)3 cathode material was prepared by a carbon-thermal reduction (CTR) process. V2O5, LiOH-H2O, NH4H2PO4 and C were used as starting materials to synthesize Li3V2(PO4)3 by sintering the mixture at 800℃for 24 h. The property of the Li3V2(PO4)3 sample was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurement. The results show that the Li3V2(PO4)3 sample has the same monoclinic structure as the Li3V2(PO4)3 sample synthesized by hydrogen reduction method. The particle size is about 1.5μm together with homogenous distribution. The initial discharge capacity of Li3V2(PO4)3 powder is 120 mA·h·g-1 at the rate of 0.1C, and the capacity retains 112 mA·h·g-1 after 30 cycles.展开更多
LiNi0.6Co0.2Mn0.2O2 was prepared from LiOH·H2O and MCO3(M=Ni,Co,Mn)by co-precipitation and subsequent heating. XRD,SEM and electrochemical measurements were used to examine the structure,morphology and electroche...LiNi0.6Co0.2Mn0.2O2 was prepared from LiOH·H2O and MCO3(M=Ni,Co,Mn)by co-precipitation and subsequent heating. XRD,SEM and electrochemical measurements were used to examine the structure,morphology and electrochemical characteristics, respectively.LiNi0.6Co0.2Mn0.2O2 samples show excellent electrochemical performances.The optimum sintering temperature and sintering time are 850℃and 20 h,respectively.The LiNi0.6Co0.2Mn0.2O2 shows the discharge capacity of 148 mA·h/g in the range of 3.0-4.3 V at the first cycle,and the discharge capacity remains 136 mA·h/g after 30 cycles.The carbonate co-precipitation method is suitable for the preparation of LiNi0.6Co0.2Mn0.2O2 cathode materials with good electrochemical performance for lithium ion batteries.展开更多
Thermoelectric （TE） performances are systematically investigated for the pellets of poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） with different organic additives and heating process as...Thermoelectric （TE） performances are systematically investigated for the pellets of poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） with different organic additives and heating process as organic TE materials. The electrical conductivity, Seebeck coefficient and thermal conductivity versus temperature are determined, respectively. It is found that there is no distinct change for the Seebeck coefficient among each sample with the additions of dimethyl sulfoxide and ethylene glycol. The thermal conductivity measured in a wide range of temperature indicates that the PEDOT：PSS pellet have an extremely low value. The highest figure of merit （ZT = 1.75×10^-3） is observed at 270K among the PEDOT：PSS pellets.展开更多
A method for the determination of trace mercury in water samples by hydride generation atomic absorption spectrophotometry after cloud point extraction was proposed in the present work. The effects of pH, concentratio...A method for the determination of trace mercury in water samples by hydride generation atomic absorption spectrophotometry after cloud point extraction was proposed in the present work. The effects of pH, concentration of surfactant, and equilibration time on cloud point extraction were discussed. The enhancement factor of 20 and the detection limit of 0.039 μg/L were obtained for mercury with relative standard deviation of 4.8% （n = 11）.展开更多
A supported Ni-B/TiO2 amorphous catalyst was prepared by impregnation and reduction. It was characterized by XRD, SAED, DSC, XPS, etc.. The catalytic activity of catalyst was measured through the hydrogenation of he...A supported Ni-B/TiO2 amorphous catalyst was prepared by impregnation and reduction. It was characterized by XRD, SAED, DSC, XPS, etc.. The catalytic activity of catalyst was measured through the hydrogenation of heavy arenes in petrochemicals for the first time.展开更多
We fabricated a silicon structure in silicate glass prepared with metallic aluminum in the starting material, using femtosecond laser irradiation. Small Si-rich structures such as Si clusters were transformed into lar...We fabricated a silicon structure in silicate glass prepared with metallic aluminum in the starting material, using femtosecond laser irradiation. Small Si-rich structures such as Si clusters were transformed into larger, but still nano-sized, Si particles by laser irradiation. These structures grew to microsize particles due to the thermite reaction promoted by heat treatment. We determined the effect of focused laser pulses on the Si deposition process using the time-resolved transient lens method. Localized high-temperature, high-pressure, and the generation of shock waves appear to be very important in forming the Si-rich structures that ultimately grow into Si particles.展开更多
Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,...Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,we report a hybrid CO_(2)ER electrocatalyst composed of layered bismuth sulfide(Bi_(2)S_(3))and bismuth oxide(Bi_(2)O_(3))supported on carrageenan derived carbon(Bi-CDC)prepared by a combined pyrolysis with hydrothermal treatment.In such 3 D hybrid,layered Bi_(2)O_(3)and Bi_(2)S_(3)are uniformly grown on nanocarbon supports.Benefiting from strong synergistic effect between Bi_(2)O_(3)/Bi_(2)S_(3)and nanocarbon,Bi-CDC-1:2 displays a high Faradic efficiency(FE)of>80%for formate production in the range of-0.9 V to-1.1 V with the maximum formate FE of 85.6%and current density of 14.1 mA·cm^(-2) at-1.0 V.Further,a positive onset potential of-0.5 V,a low Tafel slope of 112.38 mV·dec^(-1),and a slight performance loss during long-term CO_(2)ER tests are observed on Bi-CDC-1:2.Experimental results shows that the better CO_(2)ER performance of Bi-CDC-1:2 than that of Bi_(2)O_(3)can be attributed to the strong interfacial interactions between nanocarbons and Bi_(2)O_(3)/Bi_(2)S_(3).In situ ATR-FTIR measurements reveal that the rate-determining step in the CO_(2)ER is the formation of HCOO^(*) intermediated.Compared with carbon support,Bi-CDC-1:2 can promote the production of HCOO^(*) intermediate and thus promoting CO_(2)ER kinetic.展开更多
Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intri...Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.展开更多
Photonic media containing hybrid noble metal-dielectric nanocrystals(NCs)represent a wonderland of nanophotonics,with a myriad of uncharted optical functions yet to be explored.Capitalizing on the unique phase separat...Photonic media containing hybrid noble metal-dielectric nanocrystals(NCs)represent a wonderland of nanophotonics,with a myriad of uncharted optical functions yet to be explored.Capitalizing on the unique phase separation and spontaneous formation of Au-metal NCs in a gallosilicate glass,we fabricated Ni^2+-doped transparent nanoglass composites(GCs)containing Au-metal/γ-Ga2O3-dielectric NCs.Compared with GCs free of Au-metal NCs,the super broadband near-infrared emission of Ni^2+with a full width at half-maximum over280 nm is enhanced twice in the Au-metal/γ-Ga2O3 dual-phase GCs.A comparison is given as to the spontaneous emission(SPE)properties of Ni^2+in the dual-phase GCs when pumped resonantly and off-resonantly with the localized surface plasmon resonance band of the Au-metal NCs.The important role of the Au-metal NCs in the SPE enhancement is revealed by theoretical simulation based on the finite-element method.Combining the photonic engineering effect of hybrid Au-metal/γ-Ga2O3 NCs and the sensitization effect of Yb^3+on Ni^2+,a record-high enhancement factor of over 10 of the Ni^2+NIR emission is achieved,and optical gain is demonstrated in the GCs at the fiber communication wavelength.展开更多
Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(a...Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(arylsilyl)aryl triflates in good to high yields.Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis(1-methylethyl)bis[1]benzosilolo-[2,3-b:3',2'-d]thiophene,6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene,and 5,5,11,11-tetraisopropyl-5,11H-benzosi-lolo[3,2-c]silafluorene were determined by X-ray diffraction analysis.The UV absorption spectra of the(di)benzosilole derivatives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole,indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO-LUMO gaps of the λ-conjugation system.The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state,whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals,respectively.In other words,aggregation-induced emission was observed for the dibenzosiloles.Notably,5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence(λmax = 396 nm) with a quantum yield of 0.70.Density functional theory(DFT) calculations of the prepared(di)benzosiloles were also performed.展开更多
Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(a...Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(arylsilyl)aryl triflates in good to high yields.Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis(1-methylethyl)bis[1]benzosilolo-[2,3-b:3',2'-d]thiophene,6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene,and 5,5,11,11-tetraisopropyl-5,11H-benzosi lolo[3,2-c]silafluorene were determined by X-ray diffraction analysis.The UV absorption spectra of the(di)benzosilole derivatives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole,indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO-LUMO gaps of the π-conjugation system.The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state,whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals,respectively.In other words,aggregation-induced emission was observed for the dibenzosiloles.Notably,5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence(λmax = 396 nm) with a quantum yield of 0.70.Density functional theory(DFT) calculations of the prepared(di)benzosiloles were also performed.展开更多
To enhance the photodegradation ability of CeO_(2) for organic dyes,an effective strategy is to introduce oxygen vacancies(Vo).In general,the introduced Vo are simultaneously present both on the surface and in the bul...To enhance the photodegradation ability of CeO_(2) for organic dyes,an effective strategy is to introduce oxygen vacancies(Vo).In general,the introduced Vo are simultaneously present both on the surface and in the bulk of CeO_(2).The surface oxygen vacancies(Vo-s) can decrease the band gap,thus enhancing light absorption to produce more photogenerated e-for photodegradation.However,the bulk oxygen vacancies(Vo-b) will inhibit photocatalytic activity by increasing the recombination of photogene rated e-and Vo-b.Therefore,regulating the concentrations of Vo-s to Vo-b is a breakthrough for achieving the best utilization of photogene rated e-during photodegradation.We used an easy hydrothermal method to achieve tunable concentrations of Vo-s to Vo-b in CeO_(2) nanorods.The optimized CeO_(2) presents a 70.2%removal of rhodamine B after 120 min of ultraviolet-visible light irradiation,and a superior photodegradation performance of multiple organics.This tuning strategy for Vo also provides guidance for developing other advanced metal-oxide semiconductor photocatalysts for the photodegradation of organic dyes.展开更多
Most known catalytic dehydration of sugar alcohols such as D-sorbitol and D-mannitol can only produce di-dehydrated forms as major product,but monodehydrated products are also useful chemicals.Moreover,both di-and mon...Most known catalytic dehydration of sugar alcohols such as D-sorbitol and D-mannitol can only produce di-dehydrated forms as major product,but monodehydrated products are also useful chemicals.Moreover,both di-and mono-dehydration demand a high temperature(150℃ or higher),which deserves further attentions.To improve the mono-dehydration efficiency,a series of metal-containing hydrothermal carbonaceous materials(HTC)are prepared as catalyst in this work.Characterization reveals that the composition of preparative solution has a key influence on the morphology of HTC.In transformation of D-sorbitol,all HTC catalysts show low conversions in water regardless of temperature,but much better outputs are obtained in ethanol,especially at a higher temperature.When D-mannitol is selected as substrate,moderate to high conversions are obtained in both water and ethanol.On the other hand,high mono-dehydration selectivity is obtained for both sugar alcohols by using all catalysts.The origin of mono-dehydration selectivity and role of carbon component in catalysis are discussed in association with calculations.This study provides an efficient,mild,eco-friendly,and cost-effective system for mono-dehydration of sugar alcohols,which means a lot to development in new detergents or other fine chemicals.展开更多
Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.Th...Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.The origin of deterioration in processing accuracy could be interpreted in terms of the discontinuous movement of plasma in the vicinity of the focus.To reveal the effectiveness of the temporal energy modulation for smootli machining,such plasma motion was simulated by the fiidtc-d ifference time-domain method.F urt her more,photoinduced birefringence was observed using a high-speed polarization camera.展开更多
基金supported by Guangxi Natural Science Foundation (0832259)Program to Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning (GuiJiaoRen [2007]71)Research Funds of the Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment
文摘Y-doped Li3V2（PO4）3 cathode materials were prepared by a carbothermal reduction（CTR） process.The properties of the Y-doped Li3V2（PO4）3 were investigated by X-ray diffraction（XRD） and electrochemical measurements.XRD studies showed that the Y-doped Li3V2（PO4）3 had the same monoclinic structure as the undoped Li3V2（PO4）3.The Y-doped Li3V2（PO4）3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram（CV）, and electrochemical impedance spectra（EIS）.The optimal doping content of Y was x=0.03 in Li3V2-xYx（PO4）3 system.The Y-doped Li3V2（PO4）3 samples showed a better cyclic ability.The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Y-doping.The improved electrochemical perormances of the Y-doped Li3V2（PO4）3 cathode materials were attributed to the addition of Y3＋ ion by stabilizing the monoclinic structure.
基金Funded by the Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning(GuiJiaoRen [2007]71)Guangxi Natural Science Foundation(No.0832259)the Research Funds of the Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment Program to Sponsor Teams for Innovation in the Construction of Talent High-lands in Guangxi Institutions of Higher Learning(GuiJiaoRen [2007]71)
文摘Y-doped LiVPO4F cathode materials were prepared by a carbothermal reduction（CTR） process. The properties of the Y-doped LiVPOaF samples were investigated by X-ray diffraction （XRD） and electrochemical measurements. XRD studies show that the Y-doped LiVPOaF samples have the same triclinic structure as the undoped LiVPO4F. The Li extraction/insertion performances of Y-doped LiVPO4F samples were investigated through charge/discharge, cyclic voltammogram （CV） , and electrochemical impedance spectra（EIS）. The optimal doping content of Y is x=0.04 in LiYxV1-xPO4F system. The Y-doped LiVPO4F samples show a better cyclic ability. The electrode reaction reversibility is enhanced, and the charge transfer resistance is decreased through the Y-doping. The improved electrochemical performances of the Y-doped LiVF＇OaF cathode materials are atlributed to the addidon of Y^3＋ ion by stabilizing the Iriclinic structure.
基金Funded by the Guangxi Natural Science Foundation(No. 0832259)the National Basic Research Program of China (No. 2007CB613607)
文摘Cr-doped Li3V2（PO4）3 cathode materials Li3V2-xCr（PO4）3 were prepared by a carbothermal reduction（CTR） process. The properties of the Cr-doped Li3V2（PO4）3 were investigated by X-ray diffraction （XRD）, scanning electron microscopic （SEM）, and electrochemical measurements Results show that the Cr-doped Li3V2（PO4）3 has the same monoclinic structure as the undoped Li3V2（PO4）3, and the particle size of Cr-doped Li3V2（PO4）3 is smaller than that of the undoped Li3V2（PO4）3 and the smallest particle size is only about 1 1μm. The Cr-doped Li3V2（PO4）3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram （CV）, and electrochemical impedance spectra（EIS）. The optimal doping content of Cr was that x=0.04 in the Li3V2-xCrx（PO4）3 samples to achieve high discharge capacity and good cyclic stability. The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Cr-doping. The improved electrochemical performances of the Cr-doped Li3V2（PO4）3 cathode materials are attributed to the addition of Cr^3＋ ion by stabilizing the monoclinic structure.
基金Project(50302016) supported by the National Natural Science Foundation of China
文摘Li3V2(PO4)3 cathode material was prepared by a carbon-thermal reduction (CTR) process. V2O5, LiOH-H2O, NH4H2PO4 and C were used as starting materials to synthesize Li3V2(PO4)3 by sintering the mixture at 800℃for 24 h. The property of the Li3V2(PO4)3 sample was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurement. The results show that the Li3V2(PO4)3 sample has the same monoclinic structure as the Li3V2(PO4)3 sample synthesized by hydrogen reduction method. The particle size is about 1.5μm together with homogenous distribution. The initial discharge capacity of Li3V2(PO4)3 powder is 120 mA·h·g-1 at the rate of 0.1C, and the capacity retains 112 mA·h·g-1 after 30 cycles.
基金Projects(0991025,0842003-5 and 0832259)supported by Natural Science Foundation of Guangxi Province,ChinaProject supported by the Joint Graduate Innovation Talent Cultivation Base of Guangxi Province,ChinaProject (GuiJiaoRen[2007]71)supported by the Research Funds of the Guangxi Key Laboratory of Environmental Engineering,Protection and Assessment Program to Sponsor Teams for Innovationin the Construction of Talent Highlands in Guangxi Institutions of Higher Learning,China
文摘LiNi0.6Co0.2Mn0.2O2 was prepared from LiOH·H2O and MCO3(M=Ni,Co,Mn)by co-precipitation and subsequent heating. XRD,SEM and electrochemical measurements were used to examine the structure,morphology and electrochemical characteristics, respectively.LiNi0.6Co0.2Mn0.2O2 samples show excellent electrochemical performances.The optimum sintering temperature and sintering time are 850℃and 20 h,respectively.The LiNi0.6Co0.2Mn0.2O2 shows the discharge capacity of 148 mA·h/g in the range of 3.0-4.3 V at the first cycle,and the discharge capacity remains 136 mA·h/g after 30 cycles.The carbonate co-precipitation method is suitable for the preparation of LiNi0.6Co0.2Mn0.2O2 cathode materials with good electrochemical performance for lithium ion batteries.
基金Supported by the National Natural Science Foundation of China under Grant No 50663001, the Ministry of Education of China （2007-207058）, the Natural Science Foundation of Jiangxi Province （2007GZH1091）, and Fund of Jiangxi Provincial Department of Education （GJJ08369）.
文摘Thermoelectric （TE） performances are systematically investigated for the pellets of poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） with different organic additives and heating process as organic TE materials. The electrical conductivity, Seebeck coefficient and thermal conductivity versus temperature are determined, respectively. It is found that there is no distinct change for the Seebeck coefficient among each sample with the additions of dimethyl sulfoxide and ethylene glycol. The thermal conductivity measured in a wide range of temperature indicates that the PEDOT：PSS pellet have an extremely low value. The highest figure of merit （ZT = 1.75×10^-3） is observed at 270K among the PEDOT：PSS pellets.
基金Supported by the Natural Science Foundation of Tianjin（Nos.06TXTJJC14400, 07JCYBJC15900） and Young Teacher Foun-dation of Tianjin Polytechnic University （No.029624）.
文摘A method for the determination of trace mercury in water samples by hydride generation atomic absorption spectrophotometry after cloud point extraction was proposed in the present work. The effects of pH, concentration of surfactant, and equilibration time on cloud point extraction were discussed. The enhancement factor of 20 and the detection limit of 0.039 μg/L were obtained for mercury with relative standard deviation of 4.8% （n = 11）.
基金the NNSFC, RFDP, NSFTC and NNSFCTJ for the financial support (20003006, 2000005520, 99380171 and 031606211).
文摘A supported Ni-B/TiO2 amorphous catalyst was prepared by impregnation and reduction. It was characterized by XRD, SAED, DSC, XPS, etc.. The catalytic activity of catalyst was measured through the hydrogenation of heavy arenes in petrochemicals for the first time.
文摘We fabricated a silicon structure in silicate glass prepared with metallic aluminum in the starting material, using femtosecond laser irradiation. Small Si-rich structures such as Si clusters were transformed into larger, but still nano-sized, Si particles by laser irradiation. These structures grew to microsize particles due to the thermite reaction promoted by heat treatment. We determined the effect of focused laser pulses on the Si deposition process using the time-resolved transient lens method. Localized high-temperature, high-pressure, and the generation of shock waves appear to be very important in forming the Si-rich structures that ultimately grow into Si particles.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.50232030 and 50325209the Funds for Ph.D degree holders to Startup research works.
基金supported by the National Natural Science Foundation of China(21922811,21878270,22178308,and 21961160742)Jiangxi Province“double thousand plan”project(205201000020)+4 种基金the Zhejiang Provincial Natural Science Foundation of China(LR19B060002)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2019R01006)Zhejiang Key Laboratory of Marine Materials and Protective Technologies(2020K10)Key Laboratory of Marine Materials and Related Technologies,CASthe Startup Foundation for Hundred-Talent Program of Zhejiang University。
文摘Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,we report a hybrid CO_(2)ER electrocatalyst composed of layered bismuth sulfide(Bi_(2)S_(3))and bismuth oxide(Bi_(2)O_(3))supported on carrageenan derived carbon(Bi-CDC)prepared by a combined pyrolysis with hydrothermal treatment.In such 3 D hybrid,layered Bi_(2)O_(3)and Bi_(2)S_(3)are uniformly grown on nanocarbon supports.Benefiting from strong synergistic effect between Bi_(2)O_(3)/Bi_(2)S_(3)and nanocarbon,Bi-CDC-1:2 displays a high Faradic efficiency(FE)of>80%for formate production in the range of-0.9 V to-1.1 V with the maximum formate FE of 85.6%and current density of 14.1 mA·cm^(-2) at-1.0 V.Further,a positive onset potential of-0.5 V,a low Tafel slope of 112.38 mV·dec^(-1),and a slight performance loss during long-term CO_(2)ER tests are observed on Bi-CDC-1:2.Experimental results shows that the better CO_(2)ER performance of Bi-CDC-1:2 than that of Bi_(2)O_(3)can be attributed to the strong interfacial interactions between nanocarbons and Bi_(2)O_(3)/Bi_(2)S_(3).In situ ATR-FTIR measurements reveal that the rate-determining step in the CO_(2)ER is the formation of HCOO^(*) intermediated.Compared with carbon support,Bi-CDC-1:2 can promote the production of HCOO^(*) intermediate and thus promoting CO_(2)ER kinetic.
基金This work is part of the research program of the Foundation for Fundamental Research on Matter(FOM),which is financially supported by the Netherlands Organization for Fundamental Research(NWO)It is also part of an industrial partnership program between Philips and FOM.It is supported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.
基金National Natural Science Foundation of China(11774188,51872055,61635007,61925501)National Key Research and Development Program of China(2016YFF0200704)+5 种基金Natural Science Foundation of Heilongjiang Province(F2017006)Fundamental Research Funds for the Central UniversitiesOpen Fund of the Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques(South China University of Technology)Ph D Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(HEUGIP201819)111 Project to the Harbin Engineering University(B13015)Incubation Program of Universities’Preponderant Discipline of Shandong Province(03010304)。
文摘Photonic media containing hybrid noble metal-dielectric nanocrystals(NCs)represent a wonderland of nanophotonics,with a myriad of uncharted optical functions yet to be explored.Capitalizing on the unique phase separation and spontaneous formation of Au-metal NCs in a gallosilicate glass,we fabricated Ni^2+-doped transparent nanoglass composites(GCs)containing Au-metal/γ-Ga2O3-dielectric NCs.Compared with GCs free of Au-metal NCs,the super broadband near-infrared emission of Ni^2+with a full width at half-maximum over280 nm is enhanced twice in the Au-metal/γ-Ga2O3 dual-phase GCs.A comparison is given as to the spontaneous emission(SPE)properties of Ni^2+in the dual-phase GCs when pumped resonantly and off-resonantly with the localized surface plasmon resonance band of the Au-metal NCs.The important role of the Au-metal NCs in the SPE enhancement is revealed by theoretical simulation based on the finite-element method.Combining the photonic engineering effect of hybrid Au-metal/γ-Ga2O3 NCs and the sensitization effect of Yb^3+on Ni^2+,a record-high enhancement factor of over 10 of the Ni^2+NIR emission is achieved,and optical gain is demonstrated in the GCs at the fiber communication wavelength.
基金supported by Grants-in-Aid for Creative Research (16GS0209)Scientific Research (22350081)from the Ministry of Education,Culture,Sports,Science and Technology,Japan
文摘Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(arylsilyl)aryl triflates in good to high yields.Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis(1-methylethyl)bis[1]benzosilolo-[2,3-b:3',2'-d]thiophene,6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene,and 5,5,11,11-tetraisopropyl-5,11H-benzosi-lolo[3,2-c]silafluorene were determined by X-ray diffraction analysis.The UV absorption spectra of the(di)benzosilole derivatives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole,indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO-LUMO gaps of the λ-conjugation system.The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state,whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals,respectively.In other words,aggregation-induced emission was observed for the dibenzosiloles.Notably,5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence(λmax = 396 nm) with a quantum yield of 0.70.Density functional theory(DFT) calculations of the prepared(di)benzosiloles were also performed.
文摘Benzosiloles fused to heterocycles such as thiophene,benzothiophene,and benzofuran,and indole-and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-(arylsilyl)aryl triflates in good to high yields.Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis(1-methylethyl)bis[1]benzosilolo-[2,3-b:3',2'-d]thiophene,6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene,and 5,5,11,11-tetraisopropyl-5,11H-benzosi lolo[3,2-c]silafluorene were determined by X-ray diffraction analysis.The UV absorption spectra of the(di)benzosilole derivatives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole,indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO-LUMO gaps of the π-conjugation system.The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state,whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals,respectively.In other words,aggregation-induced emission was observed for the dibenzosiloles.Notably,5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence(λmax = 396 nm) with a quantum yield of 0.70.Density functional theory(DFT) calculations of the prepared(di)benzosiloles were also performed.
基金supported by the National Natural Science Foundation of China (Nos.21404054,21667019,22066017,52000163)the Key Project of the Natural Science Foundation of Jiangxi Province (No.20171ACB20016)+6 种基金the Jiangxi Province Major Academic and Technical Leaders Cultivating Object Program (No.20172BCB22014)the Science and Technology Department of Jiangxi Province (Nos.20181BCB18003,20181BAB216012,20181ACG70025,and 20192BAB206013)the Key Laboratory of Photochemical Conversion and Optoelectronic Materials,TIPC,CSA (No.PCOM201906)the Key Project of Science and Technology Research of the Jiangxi Provincial Department of Education (Nos.DA201602063,GJJ13508,and GJJ191044)the Aviation Science Foundation of China (No.2017ZF56020)the Fujian Key Laboratory of Measurement and Control System for Shore Environment (No.S1-KF1703)the Program B for Outstanding Ph D Candidate of Nanjing University (No.202002B076)。
文摘To enhance the photodegradation ability of CeO_(2) for organic dyes,an effective strategy is to introduce oxygen vacancies(Vo).In general,the introduced Vo are simultaneously present both on the surface and in the bulk of CeO_(2).The surface oxygen vacancies(Vo-s) can decrease the band gap,thus enhancing light absorption to produce more photogenerated e-for photodegradation.However,the bulk oxygen vacancies(Vo-b) will inhibit photocatalytic activity by increasing the recombination of photogene rated e-and Vo-b.Therefore,regulating the concentrations of Vo-s to Vo-b is a breakthrough for achieving the best utilization of photogene rated e-during photodegradation.We used an easy hydrothermal method to achieve tunable concentrations of Vo-s to Vo-b in CeO_(2) nanorods.The optimized CeO_(2) presents a 70.2%removal of rhodamine B after 120 min of ultraviolet-visible light irradiation,and a superior photodegradation performance of multiple organics.This tuning strategy for Vo also provides guidance for developing other advanced metal-oxide semiconductor photocatalysts for the photodegradation of organic dyes.
基金supported by the Fundamental Research Funds for the Central Universities(No.xjj2014005).
文摘Most known catalytic dehydration of sugar alcohols such as D-sorbitol and D-mannitol can only produce di-dehydrated forms as major product,but monodehydrated products are also useful chemicals.Moreover,both di-and mono-dehydration demand a high temperature(150℃ or higher),which deserves further attentions.To improve the mono-dehydration efficiency,a series of metal-containing hydrothermal carbonaceous materials(HTC)are prepared as catalyst in this work.Characterization reveals that the composition of preparative solution has a key influence on the morphology of HTC.In transformation of D-sorbitol,all HTC catalysts show low conversions in water regardless of temperature,but much better outputs are obtained in ethanol,especially at a higher temperature.When D-mannitol is selected as substrate,moderate to high conversions are obtained in both water and ethanol.On the other hand,high mono-dehydration selectivity is obtained for both sugar alcohols by using all catalysts.The origin of mono-dehydration selectivity and role of carbon component in catalysis are discussed in association with calculations.This study provides an efficient,mild,eco-friendly,and cost-effective system for mono-dehydration of sugar alcohols,which means a lot to development in new detergents or other fine chemicals.
文摘Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.The origin of deterioration in processing accuracy could be interpreted in terms of the discontinuous movement of plasma in the vicinity of the focus.To reveal the effectiveness of the temporal energy modulation for smootli machining,such plasma motion was simulated by the fiidtc-d ifference time-domain method.F urt her more,photoinduced birefringence was observed using a high-speed polarization camera.
