In this work, a novel heterojunction composite Ag_(2)S/KTa_(x)Nb_(1-x)O_(3)was designed and synthesized through a combination of hydrothermal and precipitation procedures. The Ta/Nb ratio of the KTa_(x)Nb_(1-x)O_(3)an...In this work, a novel heterojunction composite Ag_(2)S/KTa_(x)Nb_(1-x)O_(3)was designed and synthesized through a combination of hydrothermal and precipitation procedures. The Ta/Nb ratio of the KTa_(x)Nb_(1-x)O_(3)and the Ag_(2)S content were optimized. The best 0.5% Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3)(KTN) sample presents an enhanced photocatalytic performance in ammonia synthesis than KTN and Ag_(2)S. Under simulated sunlight, the NH_(3)generation rate of 0.5% Ag_(2)S/KTN reaches 2.0 times that of pure KTN. Under visible light, the reaction rate ratio of the two catalysts is 6.0.XRD, XPS, and TEM analysis revealed that Ag2S was intimately decorated on the KTN nanocubes surface, which promoted the electron transfer between the two semiconductors. The band structure investigation indicated that the Ag_(2)S/KTN heterojunction established a type-Ⅱ band alignment with intimate contact, thus realizing the effective transfer and separation of photogenerated carriers. The change in charge separation was considered as the main reason for the enhanced photocatalytic performance. Interestingly, the Ag_(2)S/KTN composite exhibited higher NH3generation performance under the combined action of ultrasonic vibration and simulated sunlight. The enhanced piezo-photocatalytic performance can be ascribed that the piezoelectric effect of KTN improved the bulk separation of charge carriers in KTN. This study not only provides a potential catalyst for photocatalytic nitrogen fixation but also shows new ideas for the design of highly efficient catalysts via semiconductor modification and external field coupling.展开更多
In this paper,Cu-doped Bi_(2)WO_(6)was synthesized via a solvothermal method and applied it in photocatalytic N_(2)immobilization.Characterization results showed the presence of a small amount of metallic Bi in the ph...In this paper,Cu-doped Bi_(2)WO_(6)was synthesized via a solvothermal method and applied it in photocatalytic N_(2)immobilization.Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst,indicating that the synthesized photocatalyst is actually Bi/Cu-Bi_(2)WO_(6)composite.The doped Cu had a valence state of+2 and most likely substituted the position of Bi^(3+).The introduced Cu did not affect the metallic Bi content,but mainly influenced the energy band structure of Bi_(2)WO_(6).The band gap was slightly narrowed,the conduction band was elevated,and the work function was reduced.The reduced work function improved the transfer and separation of charge carriers,which mainly caused the increased photoactivity.The optimized NH_(3)generation rates of Bi/Cu-Bi_(2)WO_(6)reached 624 and 243μmol·L^(-1)·g^(-1)·h^(-1)under simulated solar and visible light,and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi_(2)WO_(6),respectively.This research provides a method for improving the photocatalytic N_(2)fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N_(2)-to-NH_(3)conversion.展开更多
This paper synthesized a new type of ternary piezoelectric catalyst MoO_(x)/ZnS/ZnO (MZZ)by a one-step method.The catalytic degradation of Rhodamine B (RhB) solution (10μg/g,pH=7.0) shows that the composite catalyst ...This paper synthesized a new type of ternary piezoelectric catalyst MoO_(x)/ZnS/ZnO (MZZ)by a one-step method.The catalytic degradation of Rhodamine B (RhB) solution (10μg/g,pH=7.0) shows that the composite catalyst has excellent piezoelectric catalytic activity under ultrasonic vibration (40 k Hz).The piezoelectric degradation rate of the optimal sample reached 0.054 min^(-1),which was about 2.5 times that of pure ZnO.X-ray diffraction(XRD),X-ray photoelectron spectroscopy (XPS),Raman,transmission electron microscopy(TEM),scanning electron microscopy (SEM),and electrochemical impedance spectroscopy(EIS) technologies were used to analyze the structure,morphology,and interface charge transfer properties of the MZZ piezocatalysts.The results showed that the composite catalyst may have a core-shell structure.ZnS is coated on the surface of ZnO,while MoO_(x)adheres to the surface of ZnS.This structure endowed MZZ larger specific surface area than ZnO,which benefits the RhB adsorption.More importantly,the formed heterojunction structure between ZnS and ZnO promotes the separation of positive and negative charges induced by the piezoelectric effect.MoO_(x)species may act as a charge trap to further promote more carriers to participate in the reaction.In addition,MoO_(x)may also be beneficial in adsorbing dyes.Active species capture experiments show that superoxide radicals and holes are the main active species in piezoelectric catalytic reactions on MZZ catalysts.展开更多
This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation o...This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.展开更多
基金financially supported by National Natural Science Foundation of China (Grant No. 22172144)Nature Science Foundation of Zhejiang Province (Grant No. LY20B030004)。
文摘In this work, a novel heterojunction composite Ag_(2)S/KTa_(x)Nb_(1-x)O_(3)was designed and synthesized through a combination of hydrothermal and precipitation procedures. The Ta/Nb ratio of the KTa_(x)Nb_(1-x)O_(3)and the Ag_(2)S content were optimized. The best 0.5% Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3)(KTN) sample presents an enhanced photocatalytic performance in ammonia synthesis than KTN and Ag_(2)S. Under simulated sunlight, the NH_(3)generation rate of 0.5% Ag_(2)S/KTN reaches 2.0 times that of pure KTN. Under visible light, the reaction rate ratio of the two catalysts is 6.0.XRD, XPS, and TEM analysis revealed that Ag2S was intimately decorated on the KTN nanocubes surface, which promoted the electron transfer between the two semiconductors. The band structure investigation indicated that the Ag_(2)S/KTN heterojunction established a type-Ⅱ band alignment with intimate contact, thus realizing the effective transfer and separation of photogenerated carriers. The change in charge separation was considered as the main reason for the enhanced photocatalytic performance. Interestingly, the Ag_(2)S/KTN composite exhibited higher NH3generation performance under the combined action of ultrasonic vibration and simulated sunlight. The enhanced piezo-photocatalytic performance can be ascribed that the piezoelectric effect of KTN improved the bulk separation of charge carriers in KTN. This study not only provides a potential catalyst for photocatalytic nitrogen fixation but also shows new ideas for the design of highly efficient catalysts via semiconductor modification and external field coupling.
基金The work was financially supported by National Natural Science Foundation of China(Grant No.22172144)Natural Science Foundation of Zhejiang Province(Grant No.LY20B030004).
文摘In this paper,Cu-doped Bi_(2)WO_(6)was synthesized via a solvothermal method and applied it in photocatalytic N_(2)immobilization.Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst,indicating that the synthesized photocatalyst is actually Bi/Cu-Bi_(2)WO_(6)composite.The doped Cu had a valence state of+2 and most likely substituted the position of Bi^(3+).The introduced Cu did not affect the metallic Bi content,but mainly influenced the energy band structure of Bi_(2)WO_(6).The band gap was slightly narrowed,the conduction band was elevated,and the work function was reduced.The reduced work function improved the transfer and separation of charge carriers,which mainly caused the increased photoactivity.The optimized NH_(3)generation rates of Bi/Cu-Bi_(2)WO_(6)reached 624 and 243μmol·L^(-1)·g^(-1)·h^(-1)under simulated solar and visible light,and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi_(2)WO_(6),respectively.This research provides a method for improving the photocatalytic N_(2)fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N_(2)-to-NH_(3)conversion.
基金financially supported by National Natural Science Foundation of China (No. 22172144)Nature Science Foundation of Zhejiang Province (No. LY20B030004)。
文摘This paper synthesized a new type of ternary piezoelectric catalyst MoO_(x)/ZnS/ZnO (MZZ)by a one-step method.The catalytic degradation of Rhodamine B (RhB) solution (10μg/g,pH=7.0) shows that the composite catalyst has excellent piezoelectric catalytic activity under ultrasonic vibration (40 k Hz).The piezoelectric degradation rate of the optimal sample reached 0.054 min^(-1),which was about 2.5 times that of pure ZnO.X-ray diffraction(XRD),X-ray photoelectron spectroscopy (XPS),Raman,transmission electron microscopy(TEM),scanning electron microscopy (SEM),and electrochemical impedance spectroscopy(EIS) technologies were used to analyze the structure,morphology,and interface charge transfer properties of the MZZ piezocatalysts.The results showed that the composite catalyst may have a core-shell structure.ZnS is coated on the surface of ZnO,while MoO_(x)adheres to the surface of ZnS.This structure endowed MZZ larger specific surface area than ZnO,which benefits the RhB adsorption.More importantly,the formed heterojunction structure between ZnS and ZnO promotes the separation of positive and negative charges induced by the piezoelectric effect.MoO_(x)species may act as a charge trap to further promote more carriers to participate in the reaction.In addition,MoO_(x)may also be beneficial in adsorbing dyes.Active species capture experiments show that superoxide radicals and holes are the main active species in piezoelectric catalytic reactions on MZZ catalysts.
基金financially supported by the National Natural Science Foundation of China(Grant No.22172144).
文摘This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.
