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2018 Volume 35 Issue 8
2018, 35(8): 857-858
doi: 10.11944/j.issn.1000-0518.2018.08.180237
Abstract:
2018, 35(8): 859-870
doi: 10.11944/j.issn.1000-0518.2018.08.180152
Abstract:
White light-emitting diode(w-LED) has the advantages of long service life, environmental protection, energy saving and high safety, which has basically replaced traditional incandescent and fluorescent lamp after development of more than ten years and is considered to be the new generation lighting source. As the core material of w-LED, fluorescence conversion material directly affects the performance of the device. Therefore, the development of high-performance fluorescent conversion materials is of great importance to further enhance the performance of w-LED devices. This review mainly describes the rare-earth phosphors and inorganic quantum dots which used in solid-state lighting device. We summarize the progress of the structural design, composition and photoluminescent tuning of rare-earth phosphors and typically introduce the design and photoluminescence tuning of chalcogenide quantum dots represented by ZnS, perovskite quantum dots and carbon dots used in w-LED. Finally, the future development including the opportunity and challenge of the fluorescent conversion materials for solid state lighting is prospected.
White light-emitting diode(w-LED) has the advantages of long service life, environmental protection, energy saving and high safety, which has basically replaced traditional incandescent and fluorescent lamp after development of more than ten years and is considered to be the new generation lighting source. As the core material of w-LED, fluorescence conversion material directly affects the performance of the device. Therefore, the development of high-performance fluorescent conversion materials is of great importance to further enhance the performance of w-LED devices. This review mainly describes the rare-earth phosphors and inorganic quantum dots which used in solid-state lighting device. We summarize the progress of the structural design, composition and photoluminescent tuning of rare-earth phosphors and typically introduce the design and photoluminescence tuning of chalcogenide quantum dots represented by ZnS, perovskite quantum dots and carbon dots used in w-LED. Finally, the future development including the opportunity and challenge of the fluorescent conversion materials for solid state lighting is prospected.
2018, 35(8): 871-880
doi: 10.11944/j.issn.1000-0518.2018.08.180154
Abstract:
The development of electroluminescent light-emitting diodes(LEDs) has been received widespread attention for their potential applications in solid-state lighting technology, full-color displays due to their superior properties such as energy-saving, robust, long-lifetime and environment-friendly features. The notable advantage of electrophosphorescent LEDs is that they can simultaneously utilize both singlet and triplet exciton states which can reach to 100% internal quantum efficiency theoretically compared with those of conventional fluorescent LEDs. Therefore, it is highly desired to develop LEDs based on phosphorescent materials. In this review, we mainly discussed the latest researches on phosphorescent materials, including organometallic complexes, organic molecules, polymers, metal-organic frameworks and carbon quantum dots, etc., and focused on the applications of electrophosphorescent materials in LEDs. We hope this review will provide critical insights to inspire more exciting researches on environment-friendly phosphorescent materials for the application of electrophosphorescent LEDs in the near future.
The development of electroluminescent light-emitting diodes(LEDs) has been received widespread attention for their potential applications in solid-state lighting technology, full-color displays due to their superior properties such as energy-saving, robust, long-lifetime and environment-friendly features. The notable advantage of electrophosphorescent LEDs is that they can simultaneously utilize both singlet and triplet exciton states which can reach to 100% internal quantum efficiency theoretically compared with those of conventional fluorescent LEDs. Therefore, it is highly desired to develop LEDs based on phosphorescent materials. In this review, we mainly discussed the latest researches on phosphorescent materials, including organometallic complexes, organic molecules, polymers, metal-organic frameworks and carbon quantum dots, etc., and focused on the applications of electrophosphorescent materials in LEDs. We hope this review will provide critical insights to inspire more exciting researches on environment-friendly phosphorescent materials for the application of electrophosphorescent LEDs in the near future.
2018, 35(8): 881-889
doi: 10.11944/j.issn.1000-0518.2018.08.180130
Abstract:
Benefiting from the large specific surface area, open microstructure, tunable interlayer distance and chemical composition, the transition metals based layered double hydroxides(TM LDHs) have been widely applied and studied as efficient catalysts in recent years. This review introduces the design and applications of LDHs for electrochemical catalytic water oxidation. Illustrative examples are given on the origin of the advanced catalytic performance of TM LDHs towards water splitting, by focusing on their chemical compositions, microstructures and electronic properties. Possible strategies for further improving the catalytic performance and future development of TM LDHs are also prospected.
Benefiting from the large specific surface area, open microstructure, tunable interlayer distance and chemical composition, the transition metals based layered double hydroxides(TM LDHs) have been widely applied and studied as efficient catalysts in recent years. This review introduces the design and applications of LDHs for electrochemical catalytic water oxidation. Illustrative examples are given on the origin of the advanced catalytic performance of TM LDHs towards water splitting, by focusing on their chemical compositions, microstructures and electronic properties. Possible strategies for further improving the catalytic performance and future development of TM LDHs are also prospected.
2018, 35(8): 890-901
doi: 10.11944/j.issn.1000-0518.2018.08.180133
Abstract:
Hot electrons derived from the surface plasmon resonance of metallic nanocrystals have been demonstrated to play a promising role in promoting the efficiency of photocatalytic and photoelectrochemical solar-to-fuel generation. In this review, we try to describe the underlying mechanisms of the generation and relaxation process of hot electrons, give a discussion on the key factors that affect the efficiency of hot electron injection from metal to semiconductor, and provide an overview of the research progress on hot electron-mediated photocatalytic and photoelectrochemical water splitting. This review also outlines the critical limitations in current studies and sheds light on the possible future developments in this research field.
Hot electrons derived from the surface plasmon resonance of metallic nanocrystals have been demonstrated to play a promising role in promoting the efficiency of photocatalytic and photoelectrochemical solar-to-fuel generation. In this review, we try to describe the underlying mechanisms of the generation and relaxation process of hot electrons, give a discussion on the key factors that affect the efficiency of hot electron injection from metal to semiconductor, and provide an overview of the research progress on hot electron-mediated photocatalytic and photoelectrochemical water splitting. This review also outlines the critical limitations in current studies and sheds light on the possible future developments in this research field.
2018, 35(8): 902-915
doi: 10.11944/j.issn.1000-0518.2018.08.180177
Abstract:
The dye-sensitized solar cell(DSSC) has attracted a great attention in the solar energy conversion fields owing to its advantages including low cost, simple fabrication process, and relatively high efficiency. The component and microstructure of semiconductor photoanode as an important part of DSSC have direct roles on the photoelectrochemical performance of solar cell. Hollow micro/nano-structure can provide large surface area and high loading capacity of dyes, improve the light harvesting and promote the charge transport in photovoltaic devices. Therefore, the photoanode materials with hollow micro/nano-structures became a hot topic in recent years. This review addresses the progress of hollow micro/nano-structured photoanode materials, including hollow microsphere, hollow box, core-shell structure, hierarchical hollow microspheres, multi-shelled structure besides the pure or hybrid components. The relationships between each structure and power conversion efficiency(PCE) are analyzed especially. The facing challenge and prospect of hollow micro/nano-structured photoanode in the future are also discussed.
The dye-sensitized solar cell(DSSC) has attracted a great attention in the solar energy conversion fields owing to its advantages including low cost, simple fabrication process, and relatively high efficiency. The component and microstructure of semiconductor photoanode as an important part of DSSC have direct roles on the photoelectrochemical performance of solar cell. Hollow micro/nano-structure can provide large surface area and high loading capacity of dyes, improve the light harvesting and promote the charge transport in photovoltaic devices. Therefore, the photoanode materials with hollow micro/nano-structures became a hot topic in recent years. This review addresses the progress of hollow micro/nano-structured photoanode materials, including hollow microsphere, hollow box, core-shell structure, hierarchical hollow microspheres, multi-shelled structure besides the pure or hybrid components. The relationships between each structure and power conversion efficiency(PCE) are analyzed especially. The facing challenge and prospect of hollow micro/nano-structured photoanode in the future are also discussed.
2018, 35(8): 916-924
doi: 10.11944/j.issn.1000-0518.2018.08.180141
Abstract:
Due to the low-cost and simple fabrication processes, organometal trihalide perovskite solar cells(PSCs) have garnered recent interest in the scientific community, and their power conversion efficiencies have been rapidly increased to the levels comparable to traditional crystalline Si solar cells. However, the low stability of PSCs has obviously limited their commercialization. Among various kinds of PSCs, the one using carbon electrode(C-PSCs) as hole extraction electrode has shown the promise to address the stability issues because unstable hole transport materials were removed, while the carbon electrode is highly stable. Since first reported in 2013, much progress has been made on C-PSCs with the efficiency rapidly increasing from 6.6% to 15.9%. Herein, we have systematically reviewed the recent developments in C-PSCs, including device structure and working principles, progress on different parts of C-PSCs(electron transporting layer, perovskite layer and carbon electrode), and the issues needed to be addressed.
Due to the low-cost and simple fabrication processes, organometal trihalide perovskite solar cells(PSCs) have garnered recent interest in the scientific community, and their power conversion efficiencies have been rapidly increased to the levels comparable to traditional crystalline Si solar cells. However, the low stability of PSCs has obviously limited their commercialization. Among various kinds of PSCs, the one using carbon electrode(C-PSCs) as hole extraction electrode has shown the promise to address the stability issues because unstable hole transport materials were removed, while the carbon electrode is highly stable. Since first reported in 2013, much progress has been made on C-PSCs with the efficiency rapidly increasing from 6.6% to 15.9%. Herein, we have systematically reviewed the recent developments in C-PSCs, including device structure and working principles, progress on different parts of C-PSCs(electron transporting layer, perovskite layer and carbon electrode), and the issues needed to be addressed.
2018, 35(8): 925-931
doi: 10.11944/j.issn.1000-0518.2018.08.180127
Abstract:
Sulfur-doped titanium dioxide/titanium carbide(S-TiO2/Ti3C2)composites were prepared via in-situ hydrothermal oxidation and chemical vapor phase sulfurization using two-dimensional layered Ti3C2 as the raw material. The results show that the TiO2 nanoparticles in situ grew on the Ti3C2 nanosheets and sulphur was successfully doped into titanium dioxide. The S-TiO2/Ti3C2 composite as anode material for lithium ion batteries exhibits superior electrochemical performance. A discharge specific capacity of 288 mA·h/g can be obtained after 100 cycles at a current density of 0.2 A/g, which is much higher than those of TiO2/Ti3C2 and pure Ti3C2 electrodes. The outstanding cycle stability and discharge specific capacity of the S-TiO2/Ti3C2 electrode are attributed to following reasons:TiO2 nanoparticles electrically contacting Ti3C2 nanosheets can facilitate the interfacial electron transfer and effectively avoid the separation of the two components during the cycle. In addition, S-TiO2 can improve the conductivity of the TiO2 and produce some defects to enhance the reactivity. This work provides a new strategy for the preparation of two-dimensional composite materials through an in-situ transformation.
Sulfur-doped titanium dioxide/titanium carbide(S-TiO2/Ti3C2)composites were prepared via in-situ hydrothermal oxidation and chemical vapor phase sulfurization using two-dimensional layered Ti3C2 as the raw material. The results show that the TiO2 nanoparticles in situ grew on the Ti3C2 nanosheets and sulphur was successfully doped into titanium dioxide. The S-TiO2/Ti3C2 composite as anode material for lithium ion batteries exhibits superior electrochemical performance. A discharge specific capacity of 288 mA·h/g can be obtained after 100 cycles at a current density of 0.2 A/g, which is much higher than those of TiO2/Ti3C2 and pure Ti3C2 electrodes. The outstanding cycle stability and discharge specific capacity of the S-TiO2/Ti3C2 electrode are attributed to following reasons:TiO2 nanoparticles electrically contacting Ti3C2 nanosheets can facilitate the interfacial electron transfer and effectively avoid the separation of the two components during the cycle. In addition, S-TiO2 can improve the conductivity of the TiO2 and produce some defects to enhance the reactivity. This work provides a new strategy for the preparation of two-dimensional composite materials through an in-situ transformation.
2018, 35(8): 932-938
doi: 10.11944/j.issn.1000-0518.2018.08.180129
Abstract:
The morphology of γ-AlOOH, as a precursor to γ-Al2O3 in the liquid-phase synthesis system, is closely related with the performance of final product. In this paper, γ-AlOOH nanorods were synthesized by hydrothermal method. The aspect ratio of γ-AlOOH nanorods was modified by changing the concentration of Al3+ and the type of base. The crystal structure and morphology of the as-synthesized products were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM). The results show that the aspect ratio of γ-AlOOH nanorods can be tuned in the range of 5.9~8.0 with the increase of concentration of Al3+, and further adjusted into 8.0~10.0 by changing the type of base. Based on the analysis of the crystallization process, it is believed that the complexation reaction between aluminum ions and hydroxyl groups is accelerated by increasing the concentration of Al3+ and the base strength of precipitants. The increase of the content of Al(OH)3 is beneficial to the formation of γ-AlOOH nuclei and facilitates the oriented attachment of nuclei, leading to a significant increase of aspect ratio of nanorods. The positive impact breakdown strength of transformer oil modified by nano γ-Al2O3(volume fraction of 0.1%) obtained by sintering γ-AlOOH nanorods with a length to diameter ratio of 10.0 is 9.9% higher than that of pure oil.
The morphology of γ-AlOOH, as a precursor to γ-Al2O3 in the liquid-phase synthesis system, is closely related with the performance of final product. In this paper, γ-AlOOH nanorods were synthesized by hydrothermal method. The aspect ratio of γ-AlOOH nanorods was modified by changing the concentration of Al3+ and the type of base. The crystal structure and morphology of the as-synthesized products were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM). The results show that the aspect ratio of γ-AlOOH nanorods can be tuned in the range of 5.9~8.0 with the increase of concentration of Al3+, and further adjusted into 8.0~10.0 by changing the type of base. Based on the analysis of the crystallization process, it is believed that the complexation reaction between aluminum ions and hydroxyl groups is accelerated by increasing the concentration of Al3+ and the base strength of precipitants. The increase of the content of Al(OH)3 is beneficial to the formation of γ-AlOOH nuclei and facilitates the oriented attachment of nuclei, leading to a significant increase of aspect ratio of nanorods. The positive impact breakdown strength of transformer oil modified by nano γ-Al2O3(volume fraction of 0.1%) obtained by sintering γ-AlOOH nanorods with a length to diameter ratio of 10.0 is 9.9% higher than that of pure oil.
2018, 35(8): 939-945
doi: 10.11944/j.issn.1000-0518.2018.08.180147
Abstract:
The conductivity of commercial LiFePO4(LFP) cathode materials has been the key to improving its electrochemical performance. Porous carbon was prepared by using zeolite imidazolate framework-8(ZIF-8) to improve the conductivity of commercial LFP cathode material for enhancing its electrochemical performance. Two routes for modifying LFP are compared:1)the carbonized ZIF-8(CZIF-8) was mixed with LFP to form LFP/CZIF-8 cathode material; 2)the LFP@CZIF-8 cathode material was obtained by in situ growth and annealing of ZIF-8 on the surface of LFP. X-ray powder diffraction(XRD), N2 adsorption and desorption isotherms(BET) and Raman spectra reveal that the modified LFP still has an olivine structure, and the characteristics of graphite carbon materials with mesoporous structure appear at the same time. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) tests display that there is no link structure between LFP and CZIF-8 in the LFP/CZIF-8 samples, while LFP@CZIF-8 sample has a core-shell structure. Electrochemical impedance spectroscopy(EIS) shows that the ion transport impedance of the modified samples decreased significantly, indicating that the conductivity of LFP can be improved by these two routes. The charge-discharge cycle test proves that the two modified methods can improve the cycle performance and Coulombic efficiency of LFP cathode material. The high C rate charge-discharge test shows that the LFP/CZIF-8 sample is better than LFP@CZIF-8 sample, the discharge capacity of LFP/CZIF-8 sample can reach 57.8 mA·h/g at 10.0 C. This research provides a new idea for the modification of commercial lithium ion battery electrode materials, and lays the foundation for industrialization via the method optimization.
The conductivity of commercial LiFePO4(LFP) cathode materials has been the key to improving its electrochemical performance. Porous carbon was prepared by using zeolite imidazolate framework-8(ZIF-8) to improve the conductivity of commercial LFP cathode material for enhancing its electrochemical performance. Two routes for modifying LFP are compared:1)the carbonized ZIF-8(CZIF-8) was mixed with LFP to form LFP/CZIF-8 cathode material; 2)the LFP@CZIF-8 cathode material was obtained by in situ growth and annealing of ZIF-8 on the surface of LFP. X-ray powder diffraction(XRD), N2 adsorption and desorption isotherms(BET) and Raman spectra reveal that the modified LFP still has an olivine structure, and the characteristics of graphite carbon materials with mesoporous structure appear at the same time. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) tests display that there is no link structure between LFP and CZIF-8 in the LFP/CZIF-8 samples, while LFP@CZIF-8 sample has a core-shell structure. Electrochemical impedance spectroscopy(EIS) shows that the ion transport impedance of the modified samples decreased significantly, indicating that the conductivity of LFP can be improved by these two routes. The charge-discharge cycle test proves that the two modified methods can improve the cycle performance and Coulombic efficiency of LFP cathode material. The high C rate charge-discharge test shows that the LFP/CZIF-8 sample is better than LFP@CZIF-8 sample, the discharge capacity of LFP/CZIF-8 sample can reach 57.8 mA·h/g at 10.0 C. This research provides a new idea for the modification of commercial lithium ion battery electrode materials, and lays the foundation for industrialization via the method optimization.
2018, 35(8): 956-962
doi: 10.11944/j.issn.1000-0518.2018.08.180145
Abstract:
Transition metal sulfides have emerged as a desirable anode material for lithium-ion batteries in recent years. Among them, molybdenum disulfide(MoS2) has received intensive research attention because of its unique 2D-layered structure, which can provide an effective diffusion path for the intercalation and exfoliation of lithium ions during the electrochemical reaction process and high theoretical specific capacities(670 mA·h/g). However, as an typical semiconductor material, MoS2 suffers from the inherent low electrical conductivity and large volumetric expansion/shrinkage upon cycling, which will result in poor rate capability and rapid capacity decay that limit its large-scale applications. Much efforts have been devoted to passing these problems by optimizing MoS2 materials to nanostructures and integrating MoS2 with other conductive materials. Cobalt sulfide(Co9S8) is a metallic transition metal sulfide with relatively higher electrical conductivity but shows inferior electrochemical performance, which is possibly related to its sluggish ion transport kinetics. In this regard, the combination of MoS2 and Co9S8 into rationally designed hybrid architectures may offer synergistic advantages, which manifest overall structural merits over the individual component. Herein, we report the synthesis of uniform MoS2@Co9S8 yolk-shell spheres via solvothermal together with chemical vapor deposition method. The MoS2 and Co9S8 are homogeneously distributed throughout the entire yolk-shell spheres, which leads to a faster electron and Li-ion transport and effectively improves the cycling stability and reversible capacity. The void space in the yolk-shell structure can efficiently cushion the volume change during the discharge/charge process. The uniform mixing of the Co9S8 and MoS2 nanocrystals can also facilitate rapid ion/electron transportation and help to stabilize the cycling performance. Therefore, the as-prepared MoS2@Co9S8 yolk-shell spheres deliver superior Li storage performance with good rate capability and stable cycling performance. Especially for the lithium ion battery application, the MoS2@Co9S8 yolk-shell spheres show a remarkably reversible capacity of about 631.5 mA·h/g after 500th cycles at a current density of 0.2 A/g.
Transition metal sulfides have emerged as a desirable anode material for lithium-ion batteries in recent years. Among them, molybdenum disulfide(MoS2) has received intensive research attention because of its unique 2D-layered structure, which can provide an effective diffusion path for the intercalation and exfoliation of lithium ions during the electrochemical reaction process and high theoretical specific capacities(670 mA·h/g). However, as an typical semiconductor material, MoS2 suffers from the inherent low electrical conductivity and large volumetric expansion/shrinkage upon cycling, which will result in poor rate capability and rapid capacity decay that limit its large-scale applications. Much efforts have been devoted to passing these problems by optimizing MoS2 materials to nanostructures and integrating MoS2 with other conductive materials. Cobalt sulfide(Co9S8) is a metallic transition metal sulfide with relatively higher electrical conductivity but shows inferior electrochemical performance, which is possibly related to its sluggish ion transport kinetics. In this regard, the combination of MoS2 and Co9S8 into rationally designed hybrid architectures may offer synergistic advantages, which manifest overall structural merits over the individual component. Herein, we report the synthesis of uniform MoS2@Co9S8 yolk-shell spheres via solvothermal together with chemical vapor deposition method. The MoS2 and Co9S8 are homogeneously distributed throughout the entire yolk-shell spheres, which leads to a faster electron and Li-ion transport and effectively improves the cycling stability and reversible capacity. The void space in the yolk-shell structure can efficiently cushion the volume change during the discharge/charge process. The uniform mixing of the Co9S8 and MoS2 nanocrystals can also facilitate rapid ion/electron transportation and help to stabilize the cycling performance. Therefore, the as-prepared MoS2@Co9S8 yolk-shell spheres deliver superior Li storage performance with good rate capability and stable cycling performance. Especially for the lithium ion battery application, the MoS2@Co9S8 yolk-shell spheres show a remarkably reversible capacity of about 631.5 mA·h/g after 500th cycles at a current density of 0.2 A/g.
2018, 35(8): 963-968
doi: 10.11944/j.issn.1000-0518.2018.08.180143
Abstract:
Finding new energy has become the key to solving the energy and environmental problems. Hydrogen became the research focus because of its high energy efficiency and non-pollution. In recent years, Co9S8 is becoming a hot research topic with the excellent electrochemical hydrogen storage properties and high hydrogen storage capacity, but its anti-powering property still needs to be further improved. In this paper, TiO2 with different mass fraction coated Co9S8 electrode materials were obtained by using sol-gel and calcination methods. X-ray diffraction spectra(XRD), scanning electron microscope(SEM) and electrochemical measurement system were used to analyze the composition and hydrogen storage capacity of coating materials. The effects of TiO2 with different mass fractions on the electrochemical hydrogen storage performance were studied. The experimental results show that, when the mass fraction of TiO2 is 3%, the hydrogen storage capacity and cycling stability of the product are disirable. The maximum hydrogen storage capacity of the product is 2.03%(mass fraction), along with a favorable cycling stability of 60% after 30 cycles.
Finding new energy has become the key to solving the energy and environmental problems. Hydrogen became the research focus because of its high energy efficiency and non-pollution. In recent years, Co9S8 is becoming a hot research topic with the excellent electrochemical hydrogen storage properties and high hydrogen storage capacity, but its anti-powering property still needs to be further improved. In this paper, TiO2 with different mass fraction coated Co9S8 electrode materials were obtained by using sol-gel and calcination methods. X-ray diffraction spectra(XRD), scanning electron microscope(SEM) and electrochemical measurement system were used to analyze the composition and hydrogen storage capacity of coating materials. The effects of TiO2 with different mass fractions on the electrochemical hydrogen storage performance were studied. The experimental results show that, when the mass fraction of TiO2 is 3%, the hydrogen storage capacity and cycling stability of the product are disirable. The maximum hydrogen storage capacity of the product is 2.03%(mass fraction), along with a favorable cycling stability of 60% after 30 cycles.
2018, 35(8): 946-955
doi: 10.11944/j.issn.1000-0518.2018.08.180148
Abstract:
Designing and developing active, cost-effective and stable photocatalysts for the degradation of antibiotic pollutants are still an ongoing challenge. Herein, the fabrication of Bi4V2O11/reduced graphene oxide(BR) composite through a facile hydrothermal reaction, and the effective photocatalytic activity of BR composite towards the degradation of antibiotic pollutants under visible light are demonstrated. The active species of the photocatalytic system are proved to be h+ and·OH radicals by free radical trapping experiments. Based on the results, a reasonably reaction mechanism to explain the improved photocatalytic activity was also given. The introduction of reduced graphene oxide (rGO) can promote the effective separation of photo-generated electron-hole pairs of Bi4V2O11 materials, and ultimately increase its photocatalytic activity. As the results, the composite shows high activity and excellent stability towards the degradation of antibiotic pollutants. This method produces a high photocatalytic activity based on rGO support, providing a new avenue for designing excellent photocatalysts.
Designing and developing active, cost-effective and stable photocatalysts for the degradation of antibiotic pollutants are still an ongoing challenge. Herein, the fabrication of Bi4V2O11/reduced graphene oxide(BR) composite through a facile hydrothermal reaction, and the effective photocatalytic activity of BR composite towards the degradation of antibiotic pollutants under visible light are demonstrated. The active species of the photocatalytic system are proved to be h+ and·OH radicals by free radical trapping experiments. Based on the results, a reasonably reaction mechanism to explain the improved photocatalytic activity was also given. The introduction of reduced graphene oxide (rGO) can promote the effective separation of photo-generated electron-hole pairs of Bi4V2O11 materials, and ultimately increase its photocatalytic activity. As the results, the composite shows high activity and excellent stability towards the degradation of antibiotic pollutants. This method produces a high photocatalytic activity based on rGO support, providing a new avenue for designing excellent photocatalysts.
2018, 35(8): 969-971
doi: 10.11944/j.issn.1000-0518.2018.08.180139
Abstract:
The thermal stability and electrically responsive ability of composite material systems consist of polymer-stabilized blue phase(PSBP) and multi-wall carbon nanotubes(MWNTs) in different size were studied. The threshold voltages of electric field-induced broadening of reflection spectra can be greatly decreased by doping MWNTs, and it is found that the effect is closely related to the size of MWNTs. The threshold electric field strength is successfully decreased to about 0.1 V/μm in the MWNTs doped PSBP liquid crystalline photonic crystal, and the bandwidth is broadened from 20 nm to 310 nm under electric field with 1.3 V/μm. The materials are promising to be applied in areas of reflective-mode displays or tunable optical filters.
The thermal stability and electrically responsive ability of composite material systems consist of polymer-stabilized blue phase(PSBP) and multi-wall carbon nanotubes(MWNTs) in different size were studied. The threshold voltages of electric field-induced broadening of reflection spectra can be greatly decreased by doping MWNTs, and it is found that the effect is closely related to the size of MWNTs. The threshold electric field strength is successfully decreased to about 0.1 V/μm in the MWNTs doped PSBP liquid crystalline photonic crystal, and the bandwidth is broadened from 20 nm to 310 nm under electric field with 1.3 V/μm. The materials are promising to be applied in areas of reflective-mode displays or tunable optical filters.
2018, 35(8): 972-974
doi: 10.11944/j.issn.1000-0518.2018.08.180138
Abstract:
The use of electrospinning technology to prepare organic nonlinear optical nanofibers can effectively control the molecular orientation of nonlinear optical materials, the chromophores can achieve optimized arrangement similar to that of the organic single crystal showing macroscopic second-order nonlinear optics similar to pure chromophore molecules quality. In this paper, nonlinear optical organic salts were doped in polyvinylpyrrolidone to prepare nanofiber films with anisotropic structure, smooth surface and orderly arrangement. Kurtz nonlinear tests reflect that the second harmonic signal intensities are enhanced in a proportional manner with the increase of film thickness.
The use of electrospinning technology to prepare organic nonlinear optical nanofibers can effectively control the molecular orientation of nonlinear optical materials, the chromophores can achieve optimized arrangement similar to that of the organic single crystal showing macroscopic second-order nonlinear optics similar to pure chromophore molecules quality. In this paper, nonlinear optical organic salts were doped in polyvinylpyrrolidone to prepare nanofiber films with anisotropic structure, smooth surface and orderly arrangement. Kurtz nonlinear tests reflect that the second harmonic signal intensities are enhanced in a proportional manner with the increase of film thickness.
