Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction ...Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction is constructed by hybridizing a 3D flower like Schiff-based covalent organic framework(COF)with a porous structure g-C_(3)N_(4),and a comprehensive strategy is proposed to achieve efficient H_(2)O_(2)pro-duction yield coupling highly Rhodamine B(RhB)degradation rate.The charge carrier transfer mechanism is validated by an in-situ X-ray photoelectron spectroscopy,the density functional theory calculation,and a femtosecond transient absorption spectroscopy.Interestingly,the COF/g-C_(3)N_(4)S-scheme heterojunction exhibits better charge separation efficiency compared to bare COF and pure g-C_(3)N_(4),resulting in ameliora-tive photocatalytic activity.In addition,RhB is employed to consume photogenerated holes.Remarkably,2307μmol g^(-1)h^(-1)H_(2)O_(2)achieved over 10%-COF/g-C_(3)N_(4)composite in RhB solution and O_(2)atmosphere,and 100%-RhB degradation rate obtained at 45 min.This work improves a facile strategy to ameliorate SchiffCOF-based S-scheme heterojunction for efficient H_(2)O_(2)production with full hole-electron utilization ability.展开更多
Cooperative coupling of hydrogen peroxide(H_(2)O_(2))photosynthesis with organic pollutant degradation is promising strategy applied in chemical synthesis and environmental protection.Nonetheless,the photocatalytic pe...Cooperative coupling of hydrogen peroxide(H_(2)O_(2))photosynthesis with organic pollutant degradation is promising strategy applied in chemical synthesis and environmental protection.Nonetheless,the photocatalytic performance is limited by sluggish photogenerated carrier separation and limited redox potentials.Herein,an S-scheme heterojunction was constructed by assembling the TiO_(2)nanoparticles and a Schiff-base COF together.The formed S-scheme TiO_(2)/COF heterojunction can efficiently produce H_(2)O_(2)and degrade Rhodamine B(RhB)synchronously.The S-scheme charge transfer mechanism in TiO_(2)/COF composite is well unveiled by in situ irradiated X-ray photoelectron spectroscopy and DFT calculation.The femtosecond transient absorption spectra reveal the superior charge migration at interface between TiO_(2)and COF.The designed TiO2/COF composite shows drastically enhanced H_(2)O_(2)yield of 1326μmol·g^(-1)·h^(-1)in RhB solution,and the AQY value of 4.11%under 420 nm monochromatic light irradiation is achieved.Meanwhile,100%of RhB degraded under light irradiation for 40 min with TiO_(2)/TD COF as photocatalyst.This work exemplifies a promising approach to design COF-based S-scheme heterojunction with ameliorative photocatalytic performance for simultaneous organic pollutants degradation and H_(2)O_(2)production.展开更多
Pure ZnO exhibits low photocatalytic H_(2)O_(2)production activity due to the rapid charge recombination.To realize the spatial separation of photogenerated electrons and holes,constructing an electron transfer channe...Pure ZnO exhibits low photocatalytic H_(2)O_(2)production activity due to the rapid charge recombination.To realize the spatial separation of photogenerated electrons and holes,constructing an electron transfer channel on the ZnO surface is an effective approach.This study successfully modified the surface of ZnO using F^(-)(ZnO/F)by introducing NH4F in an aqueous phase photocatalytic system.The F^(-)is adsorbed on the ZnO surface by Coulombic force and significantly improves the photocatalytic H_(2)O_(2)production performance of ZnO,with the highest efficiency of 4137.2μmol,g·^(-1)·L^(-1)·h^(-1).The photocatalytic performance enhancement mechanism of ZnO/F is explained in terms of electron transfer dynamics by femtosecond transient absorption spectroscopy(fs-TAS)measurements.F^(-)surface modification constructs a new ultrafast electron transport pathway from the ZnO CB to F^(-),and the optimal ZnO/F exhibits the fastest interfacial electron transfer lifetime of 5.8 ps.The F^(-)surface modification effectively facilitates the charge separation,thereby increasing the number of electrons available for photocatalytic H_(2)O_(2)reaction.This study has revealed the roles of F^(-)surface modification in the photocatalytic H_(2)O_(2)production by ZnO and provides guidance for ionic modification to improve photocatalytic performance.展开更多
S-scheme heterojunction has garnered significant interest owing to its distinctive band structure and interfacial interaction.In this work,nanosheets-like Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction photocatalyst w...S-scheme heterojunction has garnered significant interest owing to its distinctive band structure and interfacial interaction.In this work,nanosheets-like Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction photocatalyst with dual surface oxygen vacancies was synthesized by epitaxial growing method.The experiment results revealed that the evolution rate of CO from CO_(2)photoreduction for optimal Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction was 219.3 mmol·g^(-1)·h^(-1),being 9.8 times greater than that of pure BiOBr.The S-scheme band structure was shown to promote sunlight utilization,raise the reduction power of photogenerated electrons,and improve the separation and transfer of photogenerated charge carriers.Moreover,the presence of dual oxygen vacancies on the interfacial surface of Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction facilitates the adsorption and activation of CO_(2)and H2O molecules.The work focuses on the combined impact of the S-scheme band structure and oxygen vacancy on the property of photocatalytic reduction of CO_(2).The study presents a straightforward strategy for the on-site creation of S-scheme heterojunction with defect.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22409128,22378103,and 52202376)the China Postdoctoral Science Foundation(No.2022TQ0316).
文摘Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction is constructed by hybridizing a 3D flower like Schiff-based covalent organic framework(COF)with a porous structure g-C_(3)N_(4),and a comprehensive strategy is proposed to achieve efficient H_(2)O_(2)pro-duction yield coupling highly Rhodamine B(RhB)degradation rate.The charge carrier transfer mechanism is validated by an in-situ X-ray photoelectron spectroscopy,the density functional theory calculation,and a femtosecond transient absorption spectroscopy.Interestingly,the COF/g-C_(3)N_(4)S-scheme heterojunction exhibits better charge separation efficiency compared to bare COF and pure g-C_(3)N_(4),resulting in ameliora-tive photocatalytic activity.In addition,RhB is employed to consume photogenerated holes.Remarkably,2307μmol g^(-1)h^(-1)H_(2)O_(2)achieved over 10%-COF/g-C_(3)N_(4)composite in RhB solution and O_(2)atmosphere,and 100%-RhB degradation rate obtained at 45 min.This work improves a facile strategy to ameliorate SchiffCOF-based S-scheme heterojunction for efficient H_(2)O_(2)production with full hole-electron utilization ability.
基金supported by National Natural Science Foundation of China(22409128,22378103,22262012).
文摘Cooperative coupling of hydrogen peroxide(H_(2)O_(2))photosynthesis with organic pollutant degradation is promising strategy applied in chemical synthesis and environmental protection.Nonetheless,the photocatalytic performance is limited by sluggish photogenerated carrier separation and limited redox potentials.Herein,an S-scheme heterojunction was constructed by assembling the TiO_(2)nanoparticles and a Schiff-base COF together.The formed S-scheme TiO_(2)/COF heterojunction can efficiently produce H_(2)O_(2)and degrade Rhodamine B(RhB)synchronously.The S-scheme charge transfer mechanism in TiO_(2)/COF composite is well unveiled by in situ irradiated X-ray photoelectron spectroscopy and DFT calculation.The femtosecond transient absorption spectra reveal the superior charge migration at interface between TiO_(2)and COF.The designed TiO2/COF composite shows drastically enhanced H_(2)O_(2)yield of 1326μmol·g^(-1)·h^(-1)in RhB solution,and the AQY value of 4.11%under 420 nm monochromatic light irradiation is achieved.Meanwhile,100%of RhB degraded under light irradiation for 40 min with TiO_(2)/TD COF as photocatalyst.This work exemplifies a promising approach to design COF-based S-scheme heterojunction with ameliorative photocatalytic performance for simultaneous organic pollutants degradation and H_(2)O_(2)production.
基金supported by National Natural Science Foundation of China(U23A20102,52202375,22469001)the Natural Science Foundation of Hubei Province of China(2022CFA001).
文摘Pure ZnO exhibits low photocatalytic H_(2)O_(2)production activity due to the rapid charge recombination.To realize the spatial separation of photogenerated electrons and holes,constructing an electron transfer channel on the ZnO surface is an effective approach.This study successfully modified the surface of ZnO using F^(-)(ZnO/F)by introducing NH4F in an aqueous phase photocatalytic system.The F^(-)is adsorbed on the ZnO surface by Coulombic force and significantly improves the photocatalytic H_(2)O_(2)production performance of ZnO,with the highest efficiency of 4137.2μmol,g·^(-1)·L^(-1)·h^(-1).The photocatalytic performance enhancement mechanism of ZnO/F is explained in terms of electron transfer dynamics by femtosecond transient absorption spectroscopy(fs-TAS)measurements.F^(-)surface modification constructs a new ultrafast electron transport pathway from the ZnO CB to F^(-),and the optimal ZnO/F exhibits the fastest interfacial electron transfer lifetime of 5.8 ps.The F^(-)surface modification effectively facilitates the charge separation,thereby increasing the number of electrons available for photocatalytic H_(2)O_(2)reaction.This study has revealed the roles of F^(-)surface modification in the photocatalytic H_(2)O_(2)production by ZnO and provides guidance for ionic modification to improve photocatalytic performance.
基金supported by National Natural Science Foundation of China(12274118,52202375)Natural Science Foundation of Hebei of China(B2022205008)Innovation Capability Improvement Plan Project of Hebei Province(22567604H).
文摘S-scheme heterojunction has garnered significant interest owing to its distinctive band structure and interfacial interaction.In this work,nanosheets-like Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction photocatalyst with dual surface oxygen vacancies was synthesized by epitaxial growing method.The experiment results revealed that the evolution rate of CO from CO_(2)photoreduction for optimal Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction was 219.3 mmol·g^(-1)·h^(-1),being 9.8 times greater than that of pure BiOBr.The S-scheme band structure was shown to promote sunlight utilization,raise the reduction power of photogenerated electrons,and improve the separation and transfer of photogenerated charge carriers.Moreover,the presence of dual oxygen vacancies on the interfacial surface of Bi_(2)O_(2)S_(0.8)F_(0.4)/BiOBr heterojunction facilitates the adsorption and activation of CO_(2)and H2O molecules.The work focuses on the combined impact of the S-scheme band structure and oxygen vacancy on the property of photocatalytic reduction of CO_(2).The study presents a straightforward strategy for the on-site creation of S-scheme heterojunction with defect.
