The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditi...The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditions.The photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 or SiO2@Fe3O4nanoparticles or coordinated with an axial azide ligand was also investigated.The results demonstrated that the photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4.The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction.The highest degradation rate for CoPz（BuS）8 loaded Al2O3 at pH = 4 after 160 min was 84.6%.However,the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz（BuS）8 loaded SiO2@Fe3O4 cannot be ignored.When electron-rich NaN3 was coordinated with CoPz（BuS）8 as an axial ligand and loaded on Al2O3,the resulting catalyst produced more active oxygen species such as O2^- and HO· to promote the quicker degradation of RhB than that by the other catalysts.For the N3-coordinated CoPz（BuS）8 loaded on Al2O3,the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics,and the degradation rate reached 77.6%after 80 min at pH = 4.展开更多
Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence o...Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.展开更多
Photocatalytic process represents a promising approach to overcome the pollution challenge associated with the antibiotics-containing wastewater.This study provides a green,efficient and novel approach to remove cepha...Photocatalytic process represents a promising approach to overcome the pollution challenge associated with the antibiotics-containing wastewater.This study provides a green,efficient and novel approach to remove cephalosporins,particularly cefoperazone sodium(CFP).Bi_(4)O_(5)Br_(2) was chosen for the first time to systematically study its degradation for CFP,including the analysis of material structure,degradation performance,the structure and toxicity of the transformation products,etc.The degradation rate results indicated that Bi_(4)O_(5)Br_(2) had an excellent catalytic activity leading to 78%CFP removal compared with the pure BiOBr(38%)within 120 min of visible light irradiation.In addition,the Bi_(4)O_(5)Br_(2) presents high stability and good organic carbon removal efficiency.The effects of the solution p H(3.12-8.75)on catalytic activity revealed that CFP was mainly photocatalyzed under acidic conditions and hydrolyzed under alkaline conditions.Combined with active species and degradation product identification,the photocatalytic degradation pathways of CFP by Bi_(4)O_(5)Br_(2) was proposed,including hydrolysis,oxidation,reduction and decarboxylation.Most importantly,the identified products were all hydrolysis rather than oxidation byproducts transformed from the intermediate ofβ-lactam bond cleavage in CFP molecule,quite different from the mostly previous studies.Furthermore,the final products were demonstrated to be less toxic through the toxicity analysis.Overall,this study illustrates the detailed mechanism of CFP degradation by Bi_(4)O_(5)Br_(2) and confirms Bi_(4)O_(5)Br_(2) to be a promising material for the photodegradation of CFP.展开更多
基金supported by National Natural Science Foundation of China (20977115, 21272281)Natural Science Foundation of Hubei Province (2014CFB919)the Science and Technology Plan Innovation Team of Wuhan City (2015070504020220)~~
文摘The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditions.The photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 or SiO2@Fe3O4nanoparticles or coordinated with an axial azide ligand was also investigated.The results demonstrated that the photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4.The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction.The highest degradation rate for CoPz（BuS）8 loaded Al2O3 at pH = 4 after 160 min was 84.6%.However,the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz（BuS）8 loaded SiO2@Fe3O4 cannot be ignored.When electron-rich NaN3 was coordinated with CoPz（BuS）8 as an axial ligand and loaded on Al2O3,the resulting catalyst produced more active oxygen species such as O2^- and HO· to promote the quicker degradation of RhB than that by the other catalysts.For the N3-coordinated CoPz（BuS）8 loaded on Al2O3,the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics,and the degradation rate reached 77.6%after 80 min at pH = 4.
基金supported by Fundamental Research Funds for the Central Universities (2662014BQ061, 2015PY120, 2015PY047, 2016PY088)the National Natural Science Foundation of China (51572101, 21502059, 21607047)~~
文摘Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.
基金the National Natural Science Foundation of China(Nos.21972073,21677086 and 21577077)Hubei Province Introduces Foreign Talents and Intelligence Projects(No.2019BJH004)+2 种基金China Postdoctoral Science Foundation(No.2018M640721)Postdoctoral Science Foundation of Hubei Province(No.G83)Open Fund of Engineering Research Center of Eco-environment in Three Gorges Reservoir Region(No.KF2019-02)。
文摘Photocatalytic process represents a promising approach to overcome the pollution challenge associated with the antibiotics-containing wastewater.This study provides a green,efficient and novel approach to remove cephalosporins,particularly cefoperazone sodium(CFP).Bi_(4)O_(5)Br_(2) was chosen for the first time to systematically study its degradation for CFP,including the analysis of material structure,degradation performance,the structure and toxicity of the transformation products,etc.The degradation rate results indicated that Bi_(4)O_(5)Br_(2) had an excellent catalytic activity leading to 78%CFP removal compared with the pure BiOBr(38%)within 120 min of visible light irradiation.In addition,the Bi_(4)O_(5)Br_(2) presents high stability and good organic carbon removal efficiency.The effects of the solution p H(3.12-8.75)on catalytic activity revealed that CFP was mainly photocatalyzed under acidic conditions and hydrolyzed under alkaline conditions.Combined with active species and degradation product identification,the photocatalytic degradation pathways of CFP by Bi_(4)O_(5)Br_(2) was proposed,including hydrolysis,oxidation,reduction and decarboxylation.Most importantly,the identified products were all hydrolysis rather than oxidation byproducts transformed from the intermediate ofβ-lactam bond cleavage in CFP molecule,quite different from the mostly previous studies.Furthermore,the final products were demonstrated to be less toxic through the toxicity analysis.Overall,this study illustrates the detailed mechanism of CFP degradation by Bi_(4)O_(5)Br_(2) and confirms Bi_(4)O_(5)Br_(2) to be a promising material for the photodegradation of CFP.
