A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is a...A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is assigned to monoclinic and tetragonal mix-crystal phase. Fibers lengths can reach several micrometers and diameters range from 0.5 μm to 3 μm. Compared with pure TiO2 and Bi2O3, TiO2/Bi2O3 samples display better absorption in visible light region. Photocatalytic activity was evaluated by degradation of MB under visible light irradiation. TiO2/Bi2O3 microfibers exhibite much higher activity than pure TiO2 and Bi2O3, and 22.84%TiO2/Bi2O3 can achieve the decomposition of about 95%MB, which is attributed to synergistic effects of the strong visible-light absorption of TiO2/Bi2O3 microfibers and the heterojunction formed between TiO2 and Bi2O3.展开更多
采用沉淀法-水热法合成了电催化Bi_(2)O_(3)-CuO复合材料.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等方法对样品的结构和形貌进行了研究.用电化学测试方法对材料电催化性能进行研究,用...采用沉淀法-水热法合成了电催化Bi_(2)O_(3)-CuO复合材料.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等方法对样品的结构和形貌进行了研究.用电化学测试方法对材料电催化性能进行研究,用气相色谱和核磁共振氢谱对产物进行分析.电催化实验结果表明,Bi_(2)O_(3)-CuO复合材料的电催化性能及对甲酸盐的选择性远高于Bi_(2)O_(3)和CuO.其中比例为1∶1的Bi_(2)O_(3)-CuO复合材料性能最好,在-1.2 V vs.RHE的电位下,甲酸盐的法拉第效率为90.3%,电流密度为20 mA/cm^(2),测试10 h保持稳定.展开更多
P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phas...P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.展开更多
Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub&...Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.展开更多
3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV exten...3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV extended the photoresponse to near-infrared region,which showed obvious photothermal effect due to the introduction of MoS_(2) with broad spectrum response.MoS_(2) nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2) nanosheets,thereby forming efficient layered heterojunctions,the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5%and 99.2%,which was~4 and 7 times higher than that of the pristine Bi_(4)O_(5)I_(2),respectively.In addition,the photocatalytic hydrogen production rate reached 496.78 μmol h^(-1)g^(-1),which was~6 times higher than that of the pristine Bi_(4)O_(5)I_(2).The excellent photocatalytic performance can be ascribed to the promoted photothermal effect,as well as,the formation of compact Z-scheme layered heterojunctions.The 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites,which was conducive to the mass transfer.Moreover,the high stability of the prepared photocatalyst further promoted its potential practical application.This strategy also provides new insights for fabricating layered Zscheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.展开更多
Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation ...Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation of guest species in van der Waals(vdW)gap implemented for tunning properties has attracted much attention in recent years.We attempt to insert Ga atoms in the vdW gap between the Te layers in p-type Bi_(0.3)Sb_(1.7)Te_(3)(BST)for further improving thermoelectrics.The vdW-related defects(including extrinsic interstitial and intrinsic defects)induced by Ga intercalation can not only modulate the carrier concentration but also enhance the texture,thereby yielding excellent electrical properties,which are reflected in the power factor PF~4.43 mW·m^(-1)·K^(-2).Furthermore,the intercalation of Ga produces multi-scale lattice imperfections such as point defects,Te precipitations,and nanopores,realizing the low lattice thermal conductivity in BST-Ga samples.Ultimately,a peak zT~1.1 at 373 K is achieved in the BST-1%Ga sample and greatly improved by~22%compared to the pristine BST.The weak bonding of vdW interlayer interaction can boost the synergistic effect for advancing BST-based or other layered thermoelectrics.展开更多
基金V. ACKNOWLEDGEMENTS This work was supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department （No.2013JK0690）, and the Shaanxi Province Natural Science Foundation （No.2013JM2013）, the National Natural Science Foundation of China （No.21203160）, and the Special Research Fund of Xianyang Normal University （No. 11XSYK204）.
文摘A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is assigned to monoclinic and tetragonal mix-crystal phase. Fibers lengths can reach several micrometers and diameters range from 0.5 μm to 3 μm. Compared with pure TiO2 and Bi2O3, TiO2/Bi2O3 samples display better absorption in visible light region. Photocatalytic activity was evaluated by degradation of MB under visible light irradiation. TiO2/Bi2O3 microfibers exhibite much higher activity than pure TiO2 and Bi2O3, and 22.84%TiO2/Bi2O3 can achieve the decomposition of about 95%MB, which is attributed to synergistic effects of the strong visible-light absorption of TiO2/Bi2O3 microfibers and the heterojunction formed between TiO2 and Bi2O3.
文摘采用沉淀法-水热法合成了电催化Bi_(2)O_(3)-CuO复合材料.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等方法对样品的结构和形貌进行了研究.用电化学测试方法对材料电催化性能进行研究,用气相色谱和核磁共振氢谱对产物进行分析.电催化实验结果表明,Bi_(2)O_(3)-CuO复合材料的电催化性能及对甲酸盐的选择性远高于Bi_(2)O_(3)和CuO.其中比例为1∶1的Bi_(2)O_(3)-CuO复合材料性能最好,在-1.2 V vs.RHE的电位下,甲酸盐的法拉第效率为90.3%,电流密度为20 mA/cm^(2),测试10 h保持稳定.
基金supported by the National Natural Science Foundation of China (22169002)the Chongzuo Key Research and Development Program of China (20220603)the Counterpart Aid Project for Discipline Construction from Guangxi University(2023M02)
文摘P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.
文摘Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.
基金support of this research by the National Natural Science Foundation of China(21871078)the Natural Science Foundation of Heilongjiang Province(JQ2019B001 and B2018010)+3 种基金the Heilongjiang Postdoctoral Startup Fund(LBH-Q14135)the Heilongjiang University Science Fund for Distinguished Young Scholars(JCL201802)the Heilongjiang Provincial Institutions of Higher Learning Basic Research Funds Basic Research Projects(KJCX201909)the Heilongjiang Touyan Innovation Team Program.
文摘3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV extended the photoresponse to near-infrared region,which showed obvious photothermal effect due to the introduction of MoS_(2) with broad spectrum response.MoS_(2) nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2) nanosheets,thereby forming efficient layered heterojunctions,the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5%and 99.2%,which was~4 and 7 times higher than that of the pristine Bi_(4)O_(5)I_(2),respectively.In addition,the photocatalytic hydrogen production rate reached 496.78 μmol h^(-1)g^(-1),which was~6 times higher than that of the pristine Bi_(4)O_(5)I_(2).The excellent photocatalytic performance can be ascribed to the promoted photothermal effect,as well as,the formation of compact Z-scheme layered heterojunctions.The 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites,which was conducive to the mass transfer.Moreover,the high stability of the prepared photocatalyst further promoted its potential practical application.This strategy also provides new insights for fabricating layered Zscheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2022YFB3803900 and 2018YFA0702100)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。
文摘Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation of guest species in van der Waals(vdW)gap implemented for tunning properties has attracted much attention in recent years.We attempt to insert Ga atoms in the vdW gap between the Te layers in p-type Bi_(0.3)Sb_(1.7)Te_(3)(BST)for further improving thermoelectrics.The vdW-related defects(including extrinsic interstitial and intrinsic defects)induced by Ga intercalation can not only modulate the carrier concentration but also enhance the texture,thereby yielding excellent electrical properties,which are reflected in the power factor PF~4.43 mW·m^(-1)·K^(-2).Furthermore,the intercalation of Ga produces multi-scale lattice imperfections such as point defects,Te precipitations,and nanopores,realizing the low lattice thermal conductivity in BST-Ga samples.Ultimately,a peak zT~1.1 at 373 K is achieved in the BST-1%Ga sample and greatly improved by~22%compared to the pristine BST.The weak bonding of vdW interlayer interaction can boost the synergistic effect for advancing BST-based or other layered thermoelectrics.
