Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ ass...Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.展开更多
Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a...Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.展开更多
In this research,a novel metal-organic framework-modified biochar composite(MIL-88b@BC)was created for the first time by modifying rice husk biochar using the excellent adsorption properties of metal-organic framework...In this research,a novel metal-organic framework-modified biochar composite(MIL-88b@BC)was created for the first time by modifying rice husk biochar using the excellent adsorption properties of metal-organic framework(MOF),as well as reducing the solubility of MOF using biochar as a substrate,aiming to improve the understanding of the adsorption characteristics of rare-earth metal recycling and to predict its adsorption mechanism.Density functional theory(DFT)computations allowed for rationally constructing the adsorption model.According to DFT calculations,the primary processes involved in the adsorption of La^(3+)wereπ–πinteraction and ligand exchange,wherein the surface hydroxyl group played a crucial role.MIL-88b@BC interacted better with La^(3+)than biochar or MOF did.Accompanying batch tests with the theoretical conjecture’s verification demonstrated that the pseudosecond-order model and the Langmuir model,respectively,provided a good fit for the adsorption kinetics and isotherms.The maximum La^(3+)adsorption capacity of MOF@BC(288.89 mg g^(−1))was achieved at pH 6.0,which was significantly higher than the adsorbents’previously documented adsorption capacities.Confirming the DFT estimations,the adsorption capacity of BC@MIL-88b for La^(3+)was higher than that of MOF and BC.Additionally,MOF@BC can be recycled at least four times.To mitigate the growing scarcity of rare earth elements(REEs)and lessen their negative environmental effects,this work laid the path for effectively treating substantial volumes of wastewater produced while mining REEs.展开更多
文摘Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.
基金supported by the National Natural Science Foundation of China(Nos.52300120 and 52070144)the Fundamental Research Funds for the Central Universities(No.22120240465).
文摘Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.
基金supported by the International Science&Technology Innovation Program of Chinese Academy of Agriculture Science(CAASCFSGLCA-IEDA-202302 and CAAS-ZDRW202110)Basic Scientific Research Project of Liaoning Provincial Department of Education(JYTMS20230179)the Young Scientist Exchange Programme between the People’s Republic of China and the Republic of Korea.
文摘In this research,a novel metal-organic framework-modified biochar composite(MIL-88b@BC)was created for the first time by modifying rice husk biochar using the excellent adsorption properties of metal-organic framework(MOF),as well as reducing the solubility of MOF using biochar as a substrate,aiming to improve the understanding of the adsorption characteristics of rare-earth metal recycling and to predict its adsorption mechanism.Density functional theory(DFT)computations allowed for rationally constructing the adsorption model.According to DFT calculations,the primary processes involved in the adsorption of La^(3+)wereπ–πinteraction and ligand exchange,wherein the surface hydroxyl group played a crucial role.MIL-88b@BC interacted better with La^(3+)than biochar or MOF did.Accompanying batch tests with the theoretical conjecture’s verification demonstrated that the pseudosecond-order model and the Langmuir model,respectively,provided a good fit for the adsorption kinetics and isotherms.The maximum La^(3+)adsorption capacity of MOF@BC(288.89 mg g^(−1))was achieved at pH 6.0,which was significantly higher than the adsorbents’previously documented adsorption capacities.Confirming the DFT estimations,the adsorption capacity of BC@MIL-88b for La^(3+)was higher than that of MOF and BC.Additionally,MOF@BC can be recycled at least four times.To mitigate the growing scarcity of rare earth elements(REEs)and lessen their negative environmental effects,this work laid the path for effectively treating substantial volumes of wastewater produced while mining REEs.
