2LiFe1-xCoxPO4-Li3V2（P04）3/C was synthesized using Fel-2xCo2xVO4 as precursor which was prepared by a simple co-precipitation method. 2LiFej-xCoxPO4-Li3V2（PO4）3/C samples were characterized by X-ray diffraction （...2LiFe1-xCoxPO4-Li3V2（P04）3/C was synthesized using Fel-2xCo2xVO4 as precursor which was prepared by a simple co-precipitation method. 2LiFej-xCoxPO4-Li3V2（PO4）3/C samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. All 2LiFel-xCoxPOa-Li3V2（PO4）3/C composites are of the similar crystal structure. The XRD analysis and SEM images show that 2LiFe0.96Co0.04PO4-Li3V2（PO4）3/C sample has the best-ordered structure and the smallest particle size. The charge-discharge tests demonstrate that these powders have the best electrochemical properties with an initial discharge capacity of 144.1 mA.h/g and capacity retention of 95.6% after 100 cycles when cycled at a current density of 0.1C between 2.5 and 4.5 V.展开更多
Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to ch...Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to characterize the TiO2/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination （254 nm）. The results indicate that with the content of TiO2 increasing, the photocatalytic activity of the composite particles enhances, while the magnetism of the particles decreases. When the molar ratio of TiO2 to Fe3O4 is about 8, both the photocatalytic activity and magnetism of the TiO2/Fe3O4 particles are relatively high, and their photocatalytic activity remains well after repeated use.展开更多
Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corro...Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corrosion resistance of Ag3PO4. Herein, the Z-scheme WO3(H2O)0.333/Ag3PO4 composites are successfully prepared through microwave hydrothermal and simple stirring. The WO3(H2O)0.333/Ag3PO4 composites are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. In the degradation of organic pollutants, WO3(H2O)0.333/Ag3PO4 composites exhibit excellent performance under visible light. This is mainly attributed to the synergy of WO3(H2O)0.333 and Ag3PO4. Especially, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is the highest, and the methylene blue can be completely degraded in 4 min. In addition, the stability of the composites is also greatly enhanced. After five cycles of testing, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is not obviously decreased. However, the degradation efficiency of Ag3PO4 was only 20.2%. This indicates that adding WO3(H2O)0.333 can significantly improve the photoetching resistance of Ag3PO4. Finally, Z-scheme photocatalytic mechanism is investigated.展开更多
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
Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduct...Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduction band of Ag3PO4.In this study,A composite consisting of Bi2WO6nanosheets and Ag3PO4was developed to curb recombination of charge carriers and enhance the activity and stability of the catalyst.Formation of a Ag3PO4/Bi2WO6composite was confirmed using X‐ray diffraction,energy‐dispersive X‐ray spectroscopy,and X‐ray photoelectron spectroscopy.Photoluminescence spectroscopy provided convincing evidence that compositing Bi2WO6with Ag3PO4effectively reduced photocorrosion of Ag3PO4.The Ag3PO4/Bi2WO6composite gave a high photocatalytic performance in photodegradation of methylene blue.A degradation rate of0.61min?1was achieved;this is1.3and6.0times higher than those achieved using Ag3PO4(0.47min?1)and Bi2WO6(0.10min?1),respectively.Reactive species trapping experiments using the Ag3PO4/Bi2WO6composite showed that holes,?OH,and?O2?all played specific roles in the photodegradation process.The photocatalytic mechanism was investigated and a Z‐scheme was proposed as a plausible mechanism.展开更多
The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reducti...The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.展开更多
The modification effects of ytterbium(Yb), Na_3PO_4 and Yb + Na_3PO_4 on primary Mg_2Si phase in Mg-4Si alloys were investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy...The modification effects of ytterbium(Yb), Na_3PO_4 and Yb + Na_3PO_4 on primary Mg_2Si phase in Mg-4Si alloys were investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis in this work. The results indicate that the morphology of the primary Mg_2Si phase apparently changes from coarse dendrites to fine dispersive polygonal particles and the mean size decreases from 276.6 μm to 7.1 μm, with combined modification of 0.8wt.% Yb and 2.64 wt.% Na_3PO_4. Such a morphological evolution results in improvement in the ultimate tensile strength and elongation of the alloys as compared to the base alloy. This may be attributed to the formation of the YbP particles that acted as the heterogeneous nucleation substrates for the primary Mg_2Si particles, resulting in a refined distribution of these precipitates. The results of XRD examination show that there was no reaction between Si and Yb or Na_3PO_4. Solo addition of Yb or Na_3PO_4 into the melt has no real modification effect on the microstructure, but the primary Mg_2Si particles and α-Mg phases become coarser than that in the unmodified alloy.展开更多
The binary Ag3 P04/MIL-125-NH2(AMN-X)composites were synthesized through ion exchange-solution method,and the ternary Ag/Ag3 PO_(4)/MIL-125-NH2(AAMN-X)Z-scheme heterojunctions were prepared via the photo chemical redu...The binary Ag3 P04/MIL-125-NH2(AMN-X)composites were synthesized through ion exchange-solution method,and the ternary Ag/Ag3 PO_(4)/MIL-125-NH2(AAMN-X)Z-scheme heterojunctions were prepared via the photo chemical reduction deposition strategy.The photocatalytic hexavalent chromium(Cr(VI))sequestration over AMN-X and AAMN-X were investigated under visible light.AAMN-120 accomplished superior reduction performance due to that Ag nanoparticles(NPs)act as electrons transfer bridge to enhance the separation efficiency of photogenerated e-h+pairs,in which the reaction rates(k.value)were 2.77 and 124.2 fold higher than those of individual MIL-125-NH2 and Ag3 PO_(4),respectively.The influences of different pH values,small organic acids and coexisting ions on the photocatalytic perfo rmance of AAMN-120 were also investigated.In addition,the AAMN-120 heterojunction expressed great reusability and stability in cycling experiments.The mechanism of photocatalytic Cr(VI)was investigated and verified through photoluminescence(PL),electrochemistry,electron spin resonance(ESR),active species capture,and Pt element deposition experiments.展开更多
The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quant...The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.展开更多
基金Project(51072233) supported by National Natural Science Foundation of China
文摘2LiFe1-xCoxPO4-Li3V2（P04）3/C was synthesized using Fel-2xCo2xVO4 as precursor which was prepared by a simple co-precipitation method. 2LiFej-xCoxPO4-Li3V2（PO4）3/C samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. All 2LiFel-xCoxPOa-Li3V2（PO4）3/C composites are of the similar crystal structure. The XRD analysis and SEM images show that 2LiFe0.96Co0.04PO4-Li3V2（PO4）3/C sample has the best-ordered structure and the smallest particle size. The charge-discharge tests demonstrate that these powders have the best electrochemical properties with an initial discharge capacity of 144.1 mA.h/g and capacity retention of 95.6% after 100 cycles when cycled at a current density of 0.1C between 2.5 and 4.5 V.
基金supported by the National Natural Science Foundation of China (Nos. 50872011, 50402022, and 50672006)the National Basic Research Program of China (No. 2007CB613608)
文摘Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to characterize the TiO2/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination （254 nm）. The results indicate that with the content of TiO2 increasing, the photocatalytic activity of the composite particles enhances, while the magnetism of the particles decreases. When the molar ratio of TiO2 to Fe3O4 is about 8, both the photocatalytic activity and magnetism of the TiO2/Fe3O4 particles are relatively high, and their photocatalytic activity remains well after repeated use.
基金supported by the National Natural Science Foundation of China(51572103 and 51502106)the Distinguished Young Scholar of Anhui Province(1808085J14)+2 种基金the Foundation for Young Talents in College of Anhui Province(gxyqZD2017051)the Key Foundation of Educational Commission of Anhui Province(KJ2016SD53)the Innovation Team of Design and Application of Advanced Energetic Materials(KJ2015TD003)~~
文摘Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corrosion resistance of Ag3PO4. Herein, the Z-scheme WO3(H2O)0.333/Ag3PO4 composites are successfully prepared through microwave hydrothermal and simple stirring. The WO3(H2O)0.333/Ag3PO4 composites are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. In the degradation of organic pollutants, WO3(H2O)0.333/Ag3PO4 composites exhibit excellent performance under visible light. This is mainly attributed to the synergy of WO3(H2O)0.333 and Ag3PO4. Especially, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is the highest, and the methylene blue can be completely degraded in 4 min. In addition, the stability of the composites is also greatly enhanced. After five cycles of testing, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is not obviously decreased. However, the degradation efficiency of Ag3PO4 was only 20.2%. This indicates that adding WO3(H2O)0.333 can significantly improve the photoetching resistance of Ag3PO4. Finally, Z-scheme photocatalytic mechanism is investigated.
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supported by the National Natural Science Foundation of China(51572103,51502106)the Foundation for Young Talents in College of Anhui Province(gxyqZD201751)~~
文摘Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduction band of Ag3PO4.In this study,A composite consisting of Bi2WO6nanosheets and Ag3PO4was developed to curb recombination of charge carriers and enhance the activity and stability of the catalyst.Formation of a Ag3PO4/Bi2WO6composite was confirmed using X‐ray diffraction,energy‐dispersive X‐ray spectroscopy,and X‐ray photoelectron spectroscopy.Photoluminescence spectroscopy provided convincing evidence that compositing Bi2WO6with Ag3PO4effectively reduced photocorrosion of Ag3PO4.The Ag3PO4/Bi2WO6composite gave a high photocatalytic performance in photodegradation of methylene blue.A degradation rate of0.61min?1was achieved;this is1.3and6.0times higher than those achieved using Ag3PO4(0.47min?1)and Bi2WO6(0.10min?1),respectively.Reactive species trapping experiments using the Ag3PO4/Bi2WO6composite showed that holes,?OH,and?O2?all played specific roles in the photodegradation process.The photocatalytic mechanism was investigated and a Z‐scheme was proposed as a plausible mechanism.
基金Project supported by the National Natural Science Foundation of China(21876168)the Key Projects for Common Key Technology Innovation in Key Industries in Chongqing(cstc2016zdcy-ztzx0020-01)+1 种基金Youth Innovation Promotion Association CAS(2019376)the Graduate Innovation Project of Chongqing Technology and Business University(yjscxx201803-028-22)。
文摘The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.
基金financially supported by the Fundamental Research Funds for Central Universities(Grant No.:XDJK2015B001)
文摘The modification effects of ytterbium(Yb), Na_3PO_4 and Yb + Na_3PO_4 on primary Mg_2Si phase in Mg-4Si alloys were investigated by means of X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis in this work. The results indicate that the morphology of the primary Mg_2Si phase apparently changes from coarse dendrites to fine dispersive polygonal particles and the mean size decreases from 276.6 μm to 7.1 μm, with combined modification of 0.8wt.% Yb and 2.64 wt.% Na_3PO_4. Such a morphological evolution results in improvement in the ultimate tensile strength and elongation of the alloys as compared to the base alloy. This may be attributed to the formation of the YbP particles that acted as the heterogeneous nucleation substrates for the primary Mg_2Si particles, resulting in a refined distribution of these precipitates. The results of XRD examination show that there was no reaction between Si and Yb or Na_3PO_4. Solo addition of Yb or Na_3PO_4 into the melt has no real modification effect on the microstructure, but the primary Mg_2Si particles and α-Mg phases become coarser than that in the unmodified alloy.
文摘The binary Ag3 P04/MIL-125-NH2(AMN-X)composites were synthesized through ion exchange-solution method,and the ternary Ag/Ag3 PO_(4)/MIL-125-NH2(AAMN-X)Z-scheme heterojunctions were prepared via the photo chemical reduction deposition strategy.The photocatalytic hexavalent chromium(Cr(VI))sequestration over AMN-X and AAMN-X were investigated under visible light.AAMN-120 accomplished superior reduction performance due to that Ag nanoparticles(NPs)act as electrons transfer bridge to enhance the separation efficiency of photogenerated e-h+pairs,in which the reaction rates(k.value)were 2.77 and 124.2 fold higher than those of individual MIL-125-NH2 and Ag3 PO_(4),respectively.The influences of different pH values,small organic acids and coexisting ions on the photocatalytic perfo rmance of AAMN-120 were also investigated.In addition,the AAMN-120 heterojunction expressed great reusability and stability in cycling experiments.The mechanism of photocatalytic Cr(VI)was investigated and verified through photoluminescence(PL),electrochemistry,electron spin resonance(ESR),active species capture,and Pt element deposition experiments.
基金supported financially by the National Natural Science Foundation of China (Nos. 51672139, 51472127 and 51272144)the Projects Supported by the Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education (No. KF2016-01)
文摘The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.
