The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed a...The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO_(2)nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO_(2)@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g^(−1)at 0.05 A g^(−1)(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge–discharge cycling.Anodes based on the optimized SnO_(2)@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g^(−1),and capacity retention of over 70.4%was maintained at a high areal loading of 3.4 mg cm^(−2),highly desirable for high energy density SIBs to rival the current benchmark LIBs.展开更多
A series of Ce1-xFexO2 （x=0, 0.2, 0.4, 0.6, 0.8, 1） complex oxide catalysts were prepared using the coprecipitation method. The catalysts were characterized by means of XRD and H2-TPR. The reactions between methane ...A series of Ce1-xFexO2 （x=0, 0.2, 0.4, 0.6, 0.8, 1） complex oxide catalysts were prepared using the coprecipitation method. The catalysts were characterized by means of XRD and H2-TPR. The reactions between methane and lattice oxygen from the complex oxides were investigated. The characteristic results revealed that the combination of Ce and Fe oxide in the catalysts could lower the temperature necessary to reduce the cerium oxide. The catalytic activity for selective CH4 oxidation was strongly influenced by dropped Fe species. Adding the appropriate amount of Fe2O3 to CeO2 could promote the action between CH4 and CeO2. Dispersed Fe2O3 first returned to the original state and would then virtually form the Fe species on the catalyst, which could be considered as the active site for selective CH4 oxidation. The appearance of carbon formation was significant and the oxidation of carbon appeared to be the rate-determining step; the amounts of surface reducible oxygen species in CeO2 were also relevant to the activity. Among all the catalysts, Ce0.6Fe0.402 exhibited the best activity, which converted 94.52% of CH4 at 900 ℃.展开更多
A series of copper (Ⅱ) complexes with pyridine N- oxide- 2- ylmethylidened-ithiocarbazates as ligands were synthesized and characterized by IR spectra, electronic spectra and magnetic moments measurement at room temp...A series of copper (Ⅱ) complexes with pyridine N- oxide- 2- ylmethylidened-ithiocarbazates as ligands were synthesized and characterized by IR spectra, electronic spectra and magnetic moments measurement at room temperature. Variable temperature magnetic susceptibilites (3-300K) of four complexs were measured and fitted with the Bleaney-Bowers dimer equation by considering the magnetic interaction between molecules. The fitting results show the existence of intramolecular ferromagnetic interactions and intermolecu-lar anti-ferromagnetic interactions in these copper( Ⅱ) complexes.展开更多
The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The ...The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.展开更多
Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （...Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （SEM）. The catalytic activity for soot combustion was evaluated by the Temperature-Programmed Reaction （TPO） technique. The results demonstrated that the substitution quality of K^＋ for La^3＋ at the A-site would increase the catalytic activities of La2-xKxCuO4 for soot combustion greatly; the substitution quality affected the structure and catalytic activity obviously. The La1.8K0.2CuO4 complex oxides with tetrahedral structures had the best catalytic activity for soot combustion, and the ignition temperature of soot combustion was lowered from 490 to 320 ℃.展开更多
The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot co...The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot combustion was evaluated by temperature-programmed reaction （TPO） technique. The results demonstrate that the substitution of K^＋ for La^3＋ at A-site will increase the catalytic activities of La2-xKxCuO4 to soot combustion greatly, and the substitution quantity affects the structure and catalytic activity obviously. The La1.8 K0.2 CuO4 complex oxides with tetrahedral structure has the best catalytic activity for soot removal reaction, the ignition temperature of soot combustion is decreased from 490 to 320℃.展开更多
Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and al...Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and alcohols with the conversion of 15.00％～34.58％ containing of 97.60％～99.80％ ketones and alcohols. The turnover numbers of these catalysts are over 3500 mol-cat. ^(-1)for 3.5 h.展开更多
Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed...Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.展开更多
In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanof...In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanofibers were characterized by dynamic light scattering（DLS）, UV–Vis spectroscopy,photoluminescence（PL） spectra, X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The SnOnanofibers deposited on fluorine-doped tin oxide（SnO） and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum（Pt） counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage（Voc）of 0.80 V, and a photocurrent density（JSC） of 3.70 m A/cmwere obtained for cells with SnOthickness of5–6 μm and cell area of 0.25 cmunder standard 1 Sun illumination（100 m W/cm）. The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.展开更多
A[H3AgI(H2O)PW11O39]3?‐TiO2/ITO electrode was fabricated by immobilizing a molecular polyoxometalate‐based water oxidation catalyst,[H3AgI(H2O)PW11O39]3?(AgPW11),on a TiO2electrode.The resulting electrode was charac...A[H3AgI(H2O)PW11O39]3?‐TiO2/ITO electrode was fabricated by immobilizing a molecular polyoxometalate‐based water oxidation catalyst,[H3AgI(H2O)PW11O39]3?(AgPW11),on a TiO2electrode.The resulting electrode was characterized by X‐ray powder diffraction,scanning electron microscopy,and energy dispersive X‐ray spectroscopy.Linear sweep voltammetry,chronoamperometry,and electrochemical impedance measurements were performed in aqueous Na2SO4solution(0.1molL?1).We found that a higher applied voltage led to better catalytic performance by AgPW11.The AgPW11‐TiO2/ITO electrode gave currents respectively10and2.5times as high as those of the TiO2/ITO and AgNO3‐TiO2/ITO electrodes at an applied voltage of1.5V vs Ag/AgCl.This result was attributed to the lower charge transfer resistance at the electrode‐electrolyte interface for the AgPW11‐TiO2/ITO electrode.Under illumination,the photocurrent was not obviously enhanced although the total anode current increased.The AgPW11‐TiO2/ITO electrode was relatively stable.Cyclic voltammetry of AgPW11was performed in phosphate buffer solution(0.1mol L?1).We found that oxidation of AgPW11was a quasi‐reversible process related to one‐electron and one‐proton transfer.We deduced that disproportionation of the oxidized[H2AgII(H2O)PW11O39]3?might have occurred and the resulting[H3AgIIIOPW11O39]3?oxidized water to O2.展开更多
A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluore...A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380（6）, b = 8.0402（7）, c = 13.5094（11） , α = 104.269（1）, β = 93.604（1）, γ = 98.349（1）°, V = 780.93（11） 3, Mr = 765.00, Dc = 1.627 g/cm3, F（000） = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ（I） and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.展开更多
基金funded by the Zhengzhou Materials Genome Institute,the National Talents Program of China,and Key Innovation Projects of the Zhengzhou Municipal City of China.
文摘The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO_(2)nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO_(2)@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g^(−1)at 0.05 A g^(−1)(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge–discharge cycling.Anodes based on the optimized SnO_(2)@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g^(−1),and capacity retention of over 70.4%was maintained at a high areal loading of 3.4 mg cm^(−2),highly desirable for high energy density SIBs to rival the current benchmark LIBs.
基金the National Natural Science Foundation of China (50574046)National Natural Science Foundation of Major Research Projects (90610035)+1 种基金Natural Science Foundation of Yunnan Province (2004E0058Q)High School Doctoral Subject Special Science and Re- search Foundation of Ministry of Education (20040674005)
文摘A series of Ce1-xFexO2 （x=0, 0.2, 0.4, 0.6, 0.8, 1） complex oxide catalysts were prepared using the coprecipitation method. The catalysts were characterized by means of XRD and H2-TPR. The reactions between methane and lattice oxygen from the complex oxides were investigated. The characteristic results revealed that the combination of Ce and Fe oxide in the catalysts could lower the temperature necessary to reduce the cerium oxide. The catalytic activity for selective CH4 oxidation was strongly influenced by dropped Fe species. Adding the appropriate amount of Fe2O3 to CeO2 could promote the action between CH4 and CeO2. Dispersed Fe2O3 first returned to the original state and would then virtually form the Fe species on the catalyst, which could be considered as the active site for selective CH4 oxidation. The appearance of carbon formation was significant and the oxidation of carbon appeared to be the rate-determining step; the amounts of surface reducible oxygen species in CeO2 were also relevant to the activity. Among all the catalysts, Ce0.6Fe0.402 exhibited the best activity, which converted 94.52% of CH4 at 900 ℃.
文摘A series of copper (Ⅱ) complexes with pyridine N- oxide- 2- ylmethylidened-ithiocarbazates as ligands were synthesized and characterized by IR spectra, electronic spectra and magnetic moments measurement at room temperature. Variable temperature magnetic susceptibilites (3-300K) of four complexs were measured and fitted with the Bleaney-Bowers dimer equation by considering the magnetic interaction between molecules. The fitting results show the existence of intramolecular ferromagnetic interactions and intermolecu-lar anti-ferromagnetic interactions in these copper( Ⅱ) complexes.
文摘The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.
基金Beijing Municipal Education Committee Program (KM200710017006)
文摘Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （SEM）. The catalytic activity for soot combustion was evaluated by the Temperature-Programmed Reaction （TPO） technique. The results demonstrated that the substitution quality of K^＋ for La^3＋ at the A-site would increase the catalytic activities of La2-xKxCuO4 for soot combustion greatly; the substitution quality affected the structure and catalytic activity obviously. The La1.8K0.2CuO4 complex oxides with tetrahedral structures had the best catalytic activity for soot combustion, and the ignition temperature of soot combustion was lowered from 490 to 320 ℃.
文摘The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot combustion was evaluated by temperature-programmed reaction （TPO） technique. The results demonstrate that the substitution of K^＋ for La^3＋ at A-site will increase the catalytic activities of La2-xKxCuO4 to soot combustion greatly, and the substitution quantity affects the structure and catalytic activity obviously. The La1.8 K0.2 CuO4 complex oxides with tetrahedral structure has the best catalytic activity for soot removal reaction, the ignition temperature of soot combustion is decreased from 490 to 320℃.
文摘Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and alcohols with the conversion of 15.00％～34.58％ containing of 97.60％～99.80％ ketones and alcohols. The turnover numbers of these catalysts are over 3500 mol-cat. ^(-1)for 3.5 h.
文摘Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.
基金supported by Solar Energy Research Initiative(SERI)of Department of Science and Technology(DST),Govt.of India
文摘In this study, we report an efficient CdTe-SnOquantum dot（QD） solar cell fabricated by heat-assisted drop-casting of hydrothermally synthesized CdTe QDs on electrospun SnOnanofibers. The as-prepared QDs and SnOnanofibers were characterized by dynamic light scattering（DLS）, UV–Vis spectroscopy,photoluminescence（PL） spectra, X-ray diffraction（XRD） and transmission electron microscopy（TEM）. The SnOnanofibers deposited on fluorine-doped tin oxide（SnO） and sensitized with the CdTe QDs were assembled into a solar cell by sandwiching against a platinum（Pt） counter electrode in presence of cobalt electrolyte. The efficiency of cells was investigated by anchoring QDs of varying sizes on SnO. The best photovoltaic performance of an overall power conversion efficiency of 1.10%, an open-circuit voltage（Voc）of 0.80 V, and a photocurrent density（JSC） of 3.70 m A/cmwere obtained for cells with SnOthickness of5–6 μm and cell area of 0.25 cmunder standard 1 Sun illumination（100 m W/cm）. The efficiency was investigated for the same systems under polysulfide electrolyte as well for a comparison.
基金supported by the National Natural Science Foundation of China (21573099, 21601077, 21573100)~~
文摘A[H3AgI(H2O)PW11O39]3?‐TiO2/ITO electrode was fabricated by immobilizing a molecular polyoxometalate‐based water oxidation catalyst,[H3AgI(H2O)PW11O39]3?(AgPW11),on a TiO2electrode.The resulting electrode was characterized by X‐ray powder diffraction,scanning electron microscopy,and energy dispersive X‐ray spectroscopy.Linear sweep voltammetry,chronoamperometry,and electrochemical impedance measurements were performed in aqueous Na2SO4solution(0.1molL?1).We found that a higher applied voltage led to better catalytic performance by AgPW11.The AgPW11‐TiO2/ITO electrode gave currents respectively10and2.5times as high as those of the TiO2/ITO and AgNO3‐TiO2/ITO electrodes at an applied voltage of1.5V vs Ag/AgCl.This result was attributed to the lower charge transfer resistance at the electrode‐electrolyte interface for the AgPW11‐TiO2/ITO electrode.Under illumination,the photocurrent was not obviously enhanced although the total anode current increased.The AgPW11‐TiO2/ITO electrode was relatively stable.Cyclic voltammetry of AgPW11was performed in phosphate buffer solution(0.1mol L?1).We found that oxidation of AgPW11was a quasi‐reversible process related to one‐electron and one‐proton transfer.We deduced that disproportionation of the oxidized[H2AgII(H2O)PW11O39]3?might have occurred and the resulting[H3AgIIIOPW11O39]3?oxidized water to O2.
基金supported by the National Natural Science Foundation of China (No. 20772042)
文摘A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380（6）, b = 8.0402（7）, c = 13.5094（11） , α = 104.269（1）, β = 93.604（1）, γ = 98.349（1）°, V = 780.93（11） 3, Mr = 765.00, Dc = 1.627 g/cm3, F（000） = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ（I） and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.
