Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate ...Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate photocatalysts.Herein,a novel S-scheme Sb2WO6/g-C3N4 nanocomposite was fabricated by an ultrasound-assisted method,which exhibited excellent performance for photocatalytic ppb-level NO removal.Compared with the pure constituents of the nanocomposite,the as-prepared 15%-Sb2WO6/g-C3N4 photocatalyst could remove more than 68%continuous-flowing NO(initial concentration:400 ppb)under visible-light irradiation in 30 min.The findings of the trapping experiments confirmed that•O2^–and h+were the important active species in the NO oxidation reaction.Meanwhile,the transient photocurrent response and PL spectroscopy analyses proved that the unique S-scheme structure of the samples could enhance the charge separation efficiency.In situ DRIFTS revealed that the photocatalytic reaction pathway of NO removal over the Sb2WO6/g-C3N4 nanocomposite occurred via an oxygen-induced route.The present work proposes a new concept for fabricating efficient photocatalysts for photocatalytic ppb-level NO oxidation and provides deeper insights into the mechanism of photocatalytic NO oxidation.展开更多
Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(X...Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy spectra(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Ultravioletvisible diffuse reflection spectroscopy(DRS),photocurrent and electrochemical impedance spectroscopy(EIS),electron spin resonance(ESR),respectively.Rhodamine B(Rh B)was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites.The Bi_2WO_6/2D g-C_3N_4exhibited a remarkable improvement compared with the pure Bi_2WO_6.The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites.The photocatalytic mechanism was also researched in detail through ESR analysis.展开更多
The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/...The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.展开更多
Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channe...Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channel.Herein,we present a Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)Z-scheme heterojunction prepared with an in-situ growth method based on the Sb atomic pinning effect.As revealed by the analysis of experimental and theoretical calculation results,the introduction of Sb anchors on C_(3)N_(4)leads to the formation of an Sb–N charge transfer bridge between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4),promoting interfacial charge communication over Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)heterojunction.Moreover,it can induce the heterojunction interfacial charge transfer pathway between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4)to change from type II to the type Z-scheme,enabling the change of the catalytic site from C_(3)N_(4)to Cs_(3)Sb_(2)Br_(9),thus promoting the CO_(2)activation.As a result,Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)achieves efficient CO_(2)to CO photocatalytic conversion using water as the electron source under simulated solar light irradiation(100 mW·cm^(−2)),with the yield of 198.4μmol·g^(−1)·h^(−1),which is nearly 3-fold and 9-fold over the counterpart synthesized catalyst without Sb anchors(Cs_(3)Sb_(2)Br_(9)/g–C_(3)N_(4))and pure g–C_(3)N_(4),respectively.This work provides a new alternative solution for the design of highly efficient heterojunction photocatalysts.展开更多
The films of photocatalysts have been widely used in decomposition pollutants. In this study, the films were successfully prepared from Bi2MoO6 and g-C3N4/Bi2MoO6 by a simple method, respectively. The samples were cha...The films of photocatalysts have been widely used in decomposition pollutants. In this study, the films were successfully prepared from Bi2MoO6 and g-C3N4/Bi2MoO6 by a simple method, respectively. The samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared spectroscopy（FTIR）, photoluminescence（PL）, UV-Vis diffuse reflectance spectroscopy（DRS） and electrochemical experiments to investigate crystalline structure, morphology, composition and properties. The photocatalytic activity of the photocatalyst films for the pollutants was evaluated by degradation of methylene blue（MB） in aqueous solution under visible light irradiation. Experiments revealed that the film of g-C3Na/Bi2MoO6 exhibited higher photocatalytic ability compared to the single-component photocatalyst, and proved its stability. The superior catalytic performance can be attributed to the effective separation of electron-hole pairs and the reduced rate of recombination. This work is of great value for the preparation of photocatalysts films.展开更多
文摘Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate photocatalysts.Herein,a novel S-scheme Sb2WO6/g-C3N4 nanocomposite was fabricated by an ultrasound-assisted method,which exhibited excellent performance for photocatalytic ppb-level NO removal.Compared with the pure constituents of the nanocomposite,the as-prepared 15%-Sb2WO6/g-C3N4 photocatalyst could remove more than 68%continuous-flowing NO(initial concentration:400 ppb)under visible-light irradiation in 30 min.The findings of the trapping experiments confirmed that•O2^–and h+were the important active species in the NO oxidation reaction.Meanwhile,the transient photocurrent response and PL spectroscopy analyses proved that the unique S-scheme structure of the samples could enhance the charge separation efficiency.In situ DRIFTS revealed that the photocatalytic reaction pathway of NO removal over the Sb2WO6/g-C3N4 nanocomposite occurred via an oxygen-induced route.The present work proposes a new concept for fabricating efficient photocatalysts for photocatalytic ppb-level NO oxidation and provides deeper insights into the mechanism of photocatalytic NO oxidation.
基金supported by National Nature Science Foundation of China (21476097, 21776118)Six talent peaks project in Jiangsu Province (2014-JNHB-014)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy spectra(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Ultravioletvisible diffuse reflection spectroscopy(DRS),photocurrent and electrochemical impedance spectroscopy(EIS),electron spin resonance(ESR),respectively.Rhodamine B(Rh B)was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites.The Bi_2WO_6/2D g-C_3N_4exhibited a remarkable improvement compared with the pure Bi_2WO_6.The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites.The photocatalytic mechanism was also researched in detail through ESR analysis.
基金financially supported by the Science Foundation of China University of Petroleum,Beijing(2462017YJRC048,2462018BJC005)the National Natural Science Foundation of China(51802351)~~
文摘The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.
基金financially supported by the National Key R&D Program of China(2022YFA1502902)the National Natural Science Foundation of China(U21A20286 and 22305214)+2 种基金the Natural Science Foundation of Tianjin City(17JCJQJC43800)the 111 Project of Chinathe Jiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB616)。
文摘Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channel.Herein,we present a Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)Z-scheme heterojunction prepared with an in-situ growth method based on the Sb atomic pinning effect.As revealed by the analysis of experimental and theoretical calculation results,the introduction of Sb anchors on C_(3)N_(4)leads to the formation of an Sb–N charge transfer bridge between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4),promoting interfacial charge communication over Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)heterojunction.Moreover,it can induce the heterojunction interfacial charge transfer pathway between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4)to change from type II to the type Z-scheme,enabling the change of the catalytic site from C_(3)N_(4)to Cs_(3)Sb_(2)Br_(9),thus promoting the CO_(2)activation.As a result,Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)achieves efficient CO_(2)to CO photocatalytic conversion using water as the electron source under simulated solar light irradiation(100 mW·cm^(−2)),with the yield of 198.4μmol·g^(−1)·h^(−1),which is nearly 3-fold and 9-fold over the counterpart synthesized catalyst without Sb anchors(Cs_(3)Sb_(2)Br_(9)/g–C_(3)N_(4))and pure g–C_(3)N_(4),respectively.This work provides a new alternative solution for the design of highly efficient heterojunction photocatalysts.
基金Supported by the National Natural Science Foundation of China（No.21276036）, the National Key Technology Support Program of China（No.2014BAB 12B06）, the Program for Liaoning Excellent Talents in University, China（No.LJQ2015013） and the Fundamental Research Funds for the Central Universities, China（Nos.3132014323, 3132015085）.
文摘The films of photocatalysts have been widely used in decomposition pollutants. In this study, the films were successfully prepared from Bi2MoO6 and g-C3N4/Bi2MoO6 by a simple method, respectively. The samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared spectroscopy（FTIR）, photoluminescence（PL）, UV-Vis diffuse reflectance spectroscopy（DRS） and electrochemical experiments to investigate crystalline structure, morphology, composition and properties. The photocatalytic activity of the photocatalyst films for the pollutants was evaluated by degradation of methylene blue（MB） in aqueous solution under visible light irradiation. Experiments revealed that the film of g-C3Na/Bi2MoO6 exhibited higher photocatalytic ability compared to the single-component photocatalyst, and proved its stability. The superior catalytic performance can be attributed to the effective separation of electron-hole pairs and the reduced rate of recombination. This work is of great value for the preparation of photocatalysts films.
