One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(...One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(Ti)Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant photodegradation.The NH_(2)-MIL-125(Ti)nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi_(4)O_(5)Br_(2).The as-prepared Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)presents more than 90%degradation of various pollutants,outperforming the counterpart individual ones.The various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials,in which the migration path of carriers from the material's interior to the surface can be reduced,in turn enhancing migration efficiency and separation capability significantly.A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors,radical trapping experiments and liquid chromatography mass spectrometry analysis.This work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts,as well as the effective purification of wastewater in environmental remediation.展开更多
Deep oxidation of NO molecules to nitrate species by photocatalysis with virtually no toxic byproduct NO_(2)generation is a challenging task.In this study,Ti O_(2)in-situ grows based on NH_(2)-MIL-125(Ti)(NM-125)not o...Deep oxidation of NO molecules to nitrate species by photocatalysis with virtually no toxic byproduct NO_(2)generation is a challenging task.In this study,Ti O_(2)in-situ grows based on NH_(2)-MIL-125(Ti)(NM-125)not only inhibited TiO 2agglomeration,but also contacted more tightly to obtain efficient interfacial effects,thus displaying excellent photocatalytic NO removal activity(68.08%).The formation of Ti O_(2) is directly confirmed by characterizations such as X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS).Meanwhile,UV–vis,photoluminescence,and photoelectrochemical analysis indicate that TiO_(2) formation effectively improves the optical properties.Moreover,the strong electron interaction and electron transport direction between NM-125 and Ti O_(2) are investigated by density functional theoretical(DFT)calculation.Finally,combined with the results of electron spin resonance(ESR)and in-situ FT-IR test,the intermediate processes of NO adsorption and photocatalytic oxidation reaction are discussed in depth,where the production of reactive oxygen species(ROS)under light is the key factor in the successful degradation of NO.Compared with NM-125 which can only produce·OH through photogenerated electrons since the lower valence band position,NMT-2 can directly produce·OH through photogenerated holes,thereby relieving the pressure on photogenerated electrons and producing more ROS.This study will provide reasonable guidance for the modification of NM-125 for photocatalytic removal of ppb-level NO.展开更多
Combining interfacial solar evaporation with a three-phase photocatalytic system can theoretically improve the production efficiency of ammonia.Herein,we designed a simple solar evaporator via in situ growth of TiO_(2...Combining interfacial solar evaporation with a three-phase photocatalytic system can theoretically improve the production efficiency of ammonia.Herein,we designed a simple solar evaporator via in situ growth of TiO_(2)onto hydrophilic carbon paper using a fast Joule heating method.This system had porous channels for high water evaporation rates,wide light-responsive wavelength range,effective light absorption,and potentially high catalytic activity.The lattice disorder and oxygen vacancies created by the rapid heating and cooling process could be reaction sites for nitrogen adsorption and activation.The ammonia yield in the three-phase system was up to 360.37 mol·g^(-1)·h^(-1),which was higher than the two-phase system(17.14μmol·g^(-1)·h^(-1)).Additionally,the ammonia yield rate was 73.65μmol·g^(-1)·h^(-1)in an outdoor test,demonstrating the potential for large-scale solar nitrogen reduction reaction(NRR).As detected,the activation energy for N2 reduction to NH3 was reduced to 26.3 kJ·mol^(-1),indicating that this process was facilitated by the design of the photothermal-photocatalytic system.Furthermore,density functional theory(DFT)calculations confirmed the roles of oxygen vacancies as active sites in promoting the NRR.This work provided a new approach to applying solar evaporators for the highly efficient ammonia production by the synergistic effects of photothermal and photocatalytic processes.展开更多
Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise appro...Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise approach.In this work,a novel NH2-MIL-125(Ti)/Bi2WO6 composite was constructed via self-assembly growing Bi2WO6 nanosheets on NH2-MIL-125(Ti)material.The characterization results demonstrated that NH2-MIL-125(Ti)was successfully incorporated into Bi2WO6 and the photoexcited carriers could be efficiently separated and transferred between the two components.NH2-MIL-125(Ti)/Bi2WO6 composites displayed enhanced photocatalytic activity for the removal of rhodamine B(RhB)and tetracycline(TC)under visible light irradiation,and the optimal weight ratio of NH2-MIL-125(Ti)was determined to be 7 wt%.The introduction of NH2-MIL-125(Ti)into Bi2WO6 could raise the absorption of visible light,accelerate the separation and transfer of charge carriers,and boost photocatalytic activity.This research presents a wide range of possibilities for the further development of novel composites in the field of environment purification.展开更多
NH_(2)-MIL-125(Ti)is a Ti-MOFs(MOFs:metal-organic frameworks)with high adsorption properties and is therefore widely used for wastewater purification.However,the powdered MOF material suffers from the disadvantages of...NH_(2)-MIL-125(Ti)is a Ti-MOFs(MOFs:metal-organic frameworks)with high adsorption properties and is therefore widely used for wastewater purification.However,the powdered MOF material suffers from the disadvantages of being difficult to separate and being potentially wasted due to easy agglomeration,which limits its application in practical applications.Here,a mesoporous Ti-MOF/polymer(PEG,PVA,and PAM)monolithic material was prepared by freeze casting in liquid nitrogen(-196℃)as an adsorbent for wastewater remediation.The composites could be easily picked up with tweezers and used for recovery tests.Characterization results such as XRD,BET,FT-IR,and SEM proved the successful synthesis of Ti-MOF/polymer.Adsorption tests using 100 mg/L methylene blue(MB)simulated wastewater showed that the Ti-MOF/PEG monolithic material had the best adsorption capacity.The order of adsorption was Ti-MOF@PEG10(747.4 mg/g)>Ti-MOF@PVA10(687.4 mg/g)>Ti-MOF@PAM10(633.7 mg/g)>NH_(2)-MIL-125(Ti)(571.4 mg/g).The effects of polymer dosage,different pollutants(methylene blue,methyl orange,indigo,actual textile wastewater),pH,anions,and cations on the adsorption effect of Ti-MOF/polymer were also investigated.It was demonstrated that all the above pollutants were well adsorbed by this Ti-MOF/polymer in the pH range 3-9.The adsorption isotherms and kinetic data are fully consistent with the Langmuir and pseudo-secondary models.This suggests that the adsorption between the pollutant and the adsorbent is a chemical interaction.Thermodynamic studies indicate that the adsorption process is exothermic and spontaneous.This work provides the potential methods to fabricate Ti-MOF/polymer monolith to avoid the pollution from powdery adsorbents that could be practical applications.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51302061)the Natural Science Foundation of Hebei province(Nos.E2014201076,E2020201021 and E2023201019)+3 种基金the Research Innovation Team of College of Chemistry and Environmental Science of Hebei University(No.hxkytd2102)Shenzhen Science and Technology Innovation Committee(No.JCYJ20200109141412308)Bintuan Science and Technology Program(Nos.2020DB002 and 2022DB009)CWO funding of Ghent University。
文摘One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(Ti)Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant photodegradation.The NH_(2)-MIL-125(Ti)nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi_(4)O_(5)Br_(2).The as-prepared Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)presents more than 90%degradation of various pollutants,outperforming the counterpart individual ones.The various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials,in which the migration path of carriers from the material's interior to the surface can be reduced,in turn enhancing migration efficiency and separation capability significantly.A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors,radical trapping experiments and liquid chromatography mass spectrometry analysis.This work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts,as well as the effective purification of wastewater in environmental remediation.
基金supported by the National Natural Science Foundation of China(No.22001026)Graduate Innovation Program of Chongqing Technology and Business University(No.yjscxx2023–211–38)Student Science and Technology Innovation Fund Project of Chongqing Technology and Business University(Nos.223006,233012)。
文摘Deep oxidation of NO molecules to nitrate species by photocatalysis with virtually no toxic byproduct NO_(2)generation is a challenging task.In this study,Ti O_(2)in-situ grows based on NH_(2)-MIL-125(Ti)(NM-125)not only inhibited TiO 2agglomeration,but also contacted more tightly to obtain efficient interfacial effects,thus displaying excellent photocatalytic NO removal activity(68.08%).The formation of Ti O_(2) is directly confirmed by characterizations such as X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS).Meanwhile,UV–vis,photoluminescence,and photoelectrochemical analysis indicate that TiO_(2) formation effectively improves the optical properties.Moreover,the strong electron interaction and electron transport direction between NM-125 and Ti O_(2) are investigated by density functional theoretical(DFT)calculation.Finally,combined with the results of electron spin resonance(ESR)and in-situ FT-IR test,the intermediate processes of NO adsorption and photocatalytic oxidation reaction are discussed in depth,where the production of reactive oxygen species(ROS)under light is the key factor in the successful degradation of NO.Compared with NM-125 which can only produce·OH through photogenerated electrons since the lower valence band position,NMT-2 can directly produce·OH through photogenerated holes,thereby relieving the pressure on photogenerated electrons and producing more ROS.This study will provide reasonable guidance for the modification of NM-125 for photocatalytic removal of ppb-level NO.
基金supported by the National Natural Science Foundation of China(No.22002146)Taishan Scholars Foundation of Shandong province(No.tsqn201909058)。
文摘Combining interfacial solar evaporation with a three-phase photocatalytic system can theoretically improve the production efficiency of ammonia.Herein,we designed a simple solar evaporator via in situ growth of TiO_(2)onto hydrophilic carbon paper using a fast Joule heating method.This system had porous channels for high water evaporation rates,wide light-responsive wavelength range,effective light absorption,and potentially high catalytic activity.The lattice disorder and oxygen vacancies created by the rapid heating and cooling process could be reaction sites for nitrogen adsorption and activation.The ammonia yield in the three-phase system was up to 360.37 mol·g^(-1)·h^(-1),which was higher than the two-phase system(17.14μmol·g^(-1)·h^(-1)).Additionally,the ammonia yield rate was 73.65μmol·g^(-1)·h^(-1)in an outdoor test,demonstrating the potential for large-scale solar nitrogen reduction reaction(NRR).As detected,the activation energy for N2 reduction to NH3 was reduced to 26.3 kJ·mol^(-1),indicating that this process was facilitated by the design of the photothermal-photocatalytic system.Furthermore,density functional theory(DFT)calculations confirmed the roles of oxygen vacancies as active sites in promoting the NRR.This work provided a new approach to applying solar evaporators for the highly efficient ammonia production by the synergistic effects of photothermal and photocatalytic processes.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21476098,21471069 and 21576123)and Jiangsu University Scientific Research Funding(No.11JDG0146).
文摘Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise approach.In this work,a novel NH2-MIL-125(Ti)/Bi2WO6 composite was constructed via self-assembly growing Bi2WO6 nanosheets on NH2-MIL-125(Ti)material.The characterization results demonstrated that NH2-MIL-125(Ti)was successfully incorporated into Bi2WO6 and the photoexcited carriers could be efficiently separated and transferred between the two components.NH2-MIL-125(Ti)/Bi2WO6 composites displayed enhanced photocatalytic activity for the removal of rhodamine B(RhB)and tetracycline(TC)under visible light irradiation,and the optimal weight ratio of NH2-MIL-125(Ti)was determined to be 7 wt%.The introduction of NH2-MIL-125(Ti)into Bi2WO6 could raise the absorption of visible light,accelerate the separation and transfer of charge carriers,and boost photocatalytic activity.This research presents a wide range of possibilities for the further development of novel composites in the field of environment purification.
文摘寻找具有高效、高吸附量、高选择性的吸附剂处理放射性的含铀废水,对环境保护具有现实意义.通过溶剂热法合成两种金属有机框架材料MIL-125和NH2-MIL-125,并用X-射线衍射仪(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA/DSC)等仪器对两种材料的结构和形貌分别进行表征,探究不同的初始pH、初始铀浓度、吸附时间等条件下两种材料分别对UO2^2+吸附性能的影响.结果表明:本实验成功合成了MIL-125和NH2-MIL-125两种材料;当初始pH分别为5和8时,MIL-125和NH2-MIL-125材料对UO2^2+的吸附效果最好.通过Langmuir和Freundlich方程进行热力学拟合可知,两种材料的吸附过程更符合Langmuir方程,在25℃时MIL-125、NH2-MIL-125对UO2^2+的最大吸附量分别为264.4 mg·g^-1和327.3 mg·g^-1,最佳吸附时间分别为480 min和70 min.
基金the National Natural Science Foundation of China(No.21902118)
文摘NH_(2)-MIL-125(Ti)is a Ti-MOFs(MOFs:metal-organic frameworks)with high adsorption properties and is therefore widely used for wastewater purification.However,the powdered MOF material suffers from the disadvantages of being difficult to separate and being potentially wasted due to easy agglomeration,which limits its application in practical applications.Here,a mesoporous Ti-MOF/polymer(PEG,PVA,and PAM)monolithic material was prepared by freeze casting in liquid nitrogen(-196℃)as an adsorbent for wastewater remediation.The composites could be easily picked up with tweezers and used for recovery tests.Characterization results such as XRD,BET,FT-IR,and SEM proved the successful synthesis of Ti-MOF/polymer.Adsorption tests using 100 mg/L methylene blue(MB)simulated wastewater showed that the Ti-MOF/PEG monolithic material had the best adsorption capacity.The order of adsorption was Ti-MOF@PEG10(747.4 mg/g)>Ti-MOF@PVA10(687.4 mg/g)>Ti-MOF@PAM10(633.7 mg/g)>NH_(2)-MIL-125(Ti)(571.4 mg/g).The effects of polymer dosage,different pollutants(methylene blue,methyl orange,indigo,actual textile wastewater),pH,anions,and cations on the adsorption effect of Ti-MOF/polymer were also investigated.It was demonstrated that all the above pollutants were well adsorbed by this Ti-MOF/polymer in the pH range 3-9.The adsorption isotherms and kinetic data are fully consistent with the Langmuir and pseudo-secondary models.This suggests that the adsorption between the pollutant and the adsorbent is a chemical interaction.Thermodynamic studies indicate that the adsorption process is exothermic and spontaneous.This work provides the potential methods to fabricate Ti-MOF/polymer monolith to avoid the pollution from powdery adsorbents that could be practical applications.
