The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fa...The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.展开更多
Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change...Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change the reaction equilibrium to increase the propylene yield,and the Boudouard reaction can assist in the carbon accumulation elimination.However,the efficiency of the catalysts developed so far is limited,we introduced the Cr active component during the synthesis of porous silica spheres to form a CO_(2)-ODP catalyst,with a uniform distribution of active sites via(NH_(4))_(3)[CrMo_(6)O_(24)H_(6)]·7H_(2)O produce a derivative.As anα-type Anderson series of polyoxometalates(POMs),this six octahedral structure formed by Mo participation surrounds the central atom Cr,which is more stable in structure by electrostatic effect,its derivatives generated after calcination are stably bound to the silica-based carrier,which reduces the formation of inertα-Cr_(2)O_(3)by CrO_(x)aggregation during the catalytic process.Meanwhile,the oxygen atoms rich in polyoxometalates are more likely to form Si-O bonds with the carrier,which makes the active sites evenly and stably branched in the inner wall of the pores of mesoporous silica spheres,reduces the influence of carbon accumulation,and facilitates the activation and regeneration.The CO_(2)conversion of the catalyst CrMoO_(x)@mesoporous silica spheres(MSS)is typically greater than 20%under selected ideal conditions.This synthesis method of assembling POMs with mesoporous materials opens a new pathway for developing propane dehydrogenation catalysts.Compared to traditional impregnation synthesis,this catalyst contains a lower Cr content while achieving higher CO_(2)consumption efficiency.展开更多
基金supported by the National Natural Science Foundation of China(21707173,51872341,51572209)the Science and Technology Program of Guangzhou(201707010095)+2 种基金the Start-up Funds for High-Level Talents of Sun Yat-sen University(38000-31131103)the Fundamental Research Funds for the Central Universities(19lgzd29)the China Postdoctoral Science Foundation(2017M622869)~~
文摘The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.
基金financial support by“Grassland Talents”of Inner Mongolia Autonomous Region,Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT23030)Technology Breakthrough Engineering Hydrogen Energy Field"Unveiling and Leading"Project(No.2024KJTW0018)+4 种基金“Steed plan High level Talents”of Inner Mongolia University,Carbon neutralization research project(No.STZX202218)the National Natural Science Foundation of China(No.U22A20107)Inner Mongolia Autonomous Region Natural Science Foundation(No.2023MS02002)Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion(No.MATEC2024KF011)National Key R&D Program of China(No.2022YFA1205201).
文摘Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change the reaction equilibrium to increase the propylene yield,and the Boudouard reaction can assist in the carbon accumulation elimination.However,the efficiency of the catalysts developed so far is limited,we introduced the Cr active component during the synthesis of porous silica spheres to form a CO_(2)-ODP catalyst,with a uniform distribution of active sites via(NH_(4))_(3)[CrMo_(6)O_(24)H_(6)]·7H_(2)O produce a derivative.As anα-type Anderson series of polyoxometalates(POMs),this six octahedral structure formed by Mo participation surrounds the central atom Cr,which is more stable in structure by electrostatic effect,its derivatives generated after calcination are stably bound to the silica-based carrier,which reduces the formation of inertα-Cr_(2)O_(3)by CrO_(x)aggregation during the catalytic process.Meanwhile,the oxygen atoms rich in polyoxometalates are more likely to form Si-O bonds with the carrier,which makes the active sites evenly and stably branched in the inner wall of the pores of mesoporous silica spheres,reduces the influence of carbon accumulation,and facilitates the activation and regeneration.The CO_(2)conversion of the catalyst CrMoO_(x)@mesoporous silica spheres(MSS)is typically greater than 20%under selected ideal conditions.This synthesis method of assembling POMs with mesoporous materials opens a new pathway for developing propane dehydrogenation catalysts.Compared to traditional impregnation synthesis,this catalyst contains a lower Cr content while achieving higher CO_(2)consumption efficiency.
