In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mes...In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mesoporous anatase 70 TiO2-30 SiO2-950 nanocomposite（crystallized at 950 °C for 2 h） as a precursor, NaO H as an etchant of SiO2 via a ＂creating mesopores in the pore walls＂ approach. Our strategy adopts mild conditions of creating pores such as diluted NaO H solution, appropriate temperature and solid/liquid ratio, etc. aiming at ensuring the integrities of mesopores architecture and anatase nanocrystals. XRD, TEM and N2 sorption techniques have been used to systematically investigate the physico-chemical properties of the nanocomposites. The results show that the intrawall mesopores are highly dense and uniform（average pore size 3.6 nm）, and highly link the initial mesochannels in a 3D manner while retaining mesostructural integrity. There is no significant change to either crystallinity or size of the anatase nanocrystals before and after creating the intrawall mesopores. The photocatalytic degradation rates of rhodamine B（RhB, 0.303 min^–1） and methylene blue（MB, 0.757 min^–1） dyes on the resultant nanocomposite are very high, which are 5.1 and 5.3 times that of the precursor; even up to 16.5 and 24.1 times that of Degussa P25 photocatalyst, respectively. These results clearly demonstrate that the 3D interconnected mesopores structure plays an overwhelming role to the increments of activities. The 3D mesoporous anatase TiO2-SiO2 nanocomposite exhibits unexpected-high degradation activities to RhB and MB in the mesoporous metal oxide-based materials reported so far. Additionally, the nanocomposite is considerably stable and reusable. We believe that this method would pave the way for the preparation of other 3D highly interconnected mesoporous metal oxide-based materials with ultra-high performance.展开更多
Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combi...Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.展开更多
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
Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of str...Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.展开更多
Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4...Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4/Ti O2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to Ti O2 were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), N2 sorption, Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/Ti O2 with a mass ratio of 1.5:1 exhibited the best degradation performance. Under UV, the degradation rate of g-C3N4/Ti O2 was 6.92 and 2.65 times higher than g-C3N4 and Ti O2, respectively. While under visible light, the enhancement factors became 9.27(to g-C3N4) and 7.03(to Ti O2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and Ti O2. This work suggests that hybridization can produce promising solar materials for environmental remediation.展开更多
Recently, the photocatalysts have attracted lots of attention and efforts due to their great potential for environmental remediation application. Toxic ions in water are an increasing environmental pollutant with the ...Recently, the photocatalysts have attracted lots of attention and efforts due to their great potential for environmental remediation application. Toxic ions in water are an increasing environmental pollutant with the fast development. Numerous researches have been made to develop photocatalysts to treat ionic pollutants under the illumination of ultraviolet light and visible light. Here, photocatalytic remediation of toxic ionic pollutants has been reviewed. This review summarized and discussed various photocatalysts including TiO〉 modified TiO2, metal oxides, metalsulfides, and nitrides and their recent progress in removing ionic pollutants such as heavy metal ion. The latest achievements and their future prospects of photocatalytic remediation of ion pollutant have also been reviewed.展开更多
In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiti...In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiting from the molecularly precise backbones,regular and homogeneous porosity,lightelement composition,nitrogen-rich system with unique electronic band structure of two-dimensional(2D)covalent triazine framework(CTF),as well as the huge specific surface area,superior thermal conductivity,excellent carrier mobility and mechanical properties of 2D graphene,CTF/graphene hybrid-based photocatalysts show great application potential in the field of photocatalysis.In this review,the recent development in synthesis of CTF/graphene hybrid-based photocatalysts,and their applications in photocatalytic water splitting for hydrogen production and photocatalytic degradation of pollutants are summarized.Firstly,we briefly describe the molecular structures,physicochemical properties,and synthetic strategies for CTF/graphene hybrid-based photocatalysts including solution mixing method,in-situ polymerization method and sol-gel method.We further assess the impact of different preparation methods on the structure,morphology,and interacting model between CTF and graphene in CTF/graphene hybrids.Following the various preparation process for CTF/graphene hybrid-based photocatalysts,these methods are analyzed and compared regarding their merits and demerits.Secondly,the functions of CTF/graphene hybrid-based photocatalysts obtained from different synthesis approaches that enhance the catalytic activity for photocataLytic hydrogen evolution and photocatalytic degradation of pollutants are discussed from the three aspects of light harvesting,charge separation and transfer,and surface catalysis.Particular focus has been placed on the catalytic mechanisms of CTF/graphene hybridbased photocatalysts for enhanced photocatalytic hydrogen evolution and improved photocatalytic degradation of pollutants.Then the rational manipulation of selection and building units of CTF,connecting bonds between CTF and graphene,dimensions and pore structures of CTF/graphene hybrids in design of CTF/graphene hybrid-based photocatalysts is discussed,aiming to inspire critical thinking about the effective strategies for modification of photocatalysts rather than the development of novel materials.In the end,the challenges and some future trends of CTF/graphene hybrids as advanced photocatalysts are also discussed from three aspects:catalysts design,performance stability and reaction mechanism.The approaches offer potential solutions to address the challenges of largescale production,catalyst activity and stability in the further research and development of new types of metal-free hybrid photocatalysts with high efficiency.展开更多
基金supported by the National Natural Science Foundation of China(21373056)the Science and Technology Commission of Shanghai Municipality(13DZ2275200)~~
文摘In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mesoporous anatase 70 TiO2-30 SiO2-950 nanocomposite（crystallized at 950 °C for 2 h） as a precursor, NaO H as an etchant of SiO2 via a ＂creating mesopores in the pore walls＂ approach. Our strategy adopts mild conditions of creating pores such as diluted NaO H solution, appropriate temperature and solid/liquid ratio, etc. aiming at ensuring the integrities of mesopores architecture and anatase nanocrystals. XRD, TEM and N2 sorption techniques have been used to systematically investigate the physico-chemical properties of the nanocomposites. The results show that the intrawall mesopores are highly dense and uniform（average pore size 3.6 nm）, and highly link the initial mesochannels in a 3D manner while retaining mesostructural integrity. There is no significant change to either crystallinity or size of the anatase nanocrystals before and after creating the intrawall mesopores. The photocatalytic degradation rates of rhodamine B（RhB, 0.303 min^–1） and methylene blue（MB, 0.757 min^–1） dyes on the resultant nanocomposite are very high, which are 5.1 and 5.3 times that of the precursor; even up to 16.5 and 24.1 times that of Degussa P25 photocatalyst, respectively. These results clearly demonstrate that the 3D interconnected mesopores structure plays an overwhelming role to the increments of activities. The 3D mesoporous anatase TiO2-SiO2 nanocomposite exhibits unexpected-high degradation activities to RhB and MB in the mesoporous metal oxide-based materials reported so far. Additionally, the nanocomposite is considerably stable and reusable. We believe that this method would pave the way for the preparation of other 3D highly interconnected mesoporous metal oxide-based materials with ultra-high performance.
基金financially supported by the National Natural Science Foundation of China(51872341,51572209)the Start-up Funds for High-Level Talents of Sun Yat-sen University(38000-31131105)+1 种基金the Fundamental Research Funds for the Central Universities(19lgzd29)the Science and Technology Program of Guangzhou(201707010095)~~
文摘Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.
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.
文摘Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.
基金Supported by the Innovative Research Team Program by the Ministry of Education of China(IRT13070)the Nature Science Foundation of Jiangsu Province(BK2012423,BK20130925)the Opening Project of State Key Laboratory of Materials-Oriented Chemical Engineering of China(KL13-02)
文摘Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4/Ti O2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to Ti O2 were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), N2 sorption, Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/Ti O2 with a mass ratio of 1.5:1 exhibited the best degradation performance. Under UV, the degradation rate of g-C3N4/Ti O2 was 6.92 and 2.65 times higher than g-C3N4 and Ti O2, respectively. While under visible light, the enhancement factors became 9.27(to g-C3N4) and 7.03(to Ti O2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and Ti O2. This work suggests that hybridization can produce promising solar materials for environmental remediation.
基金supported by Recruitment Program of Global Experts in Chinathe Start-up Funds from Shanghai Jiao Tong University+1 种基金the National Natural Science Foundation of China(51372151,21303103)the Foundation of Shanghai Government(15PJ1404000)
文摘Recently, the photocatalysts have attracted lots of attention and efforts due to their great potential for environmental remediation application. Toxic ions in water are an increasing environmental pollutant with the fast development. Numerous researches have been made to develop photocatalysts to treat ionic pollutants under the illumination of ultraviolet light and visible light. Here, photocatalytic remediation of toxic ionic pollutants has been reviewed. This review summarized and discussed various photocatalysts including TiO〉 modified TiO2, metal oxides, metalsulfides, and nitrides and their recent progress in removing ionic pollutants such as heavy metal ion. The latest achievements and their future prospects of photocatalytic remediation of ion pollutant have also been reviewed.
文摘In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiting from the molecularly precise backbones,regular and homogeneous porosity,lightelement composition,nitrogen-rich system with unique electronic band structure of two-dimensional(2D)covalent triazine framework(CTF),as well as the huge specific surface area,superior thermal conductivity,excellent carrier mobility and mechanical properties of 2D graphene,CTF/graphene hybrid-based photocatalysts show great application potential in the field of photocatalysis.In this review,the recent development in synthesis of CTF/graphene hybrid-based photocatalysts,and their applications in photocatalytic water splitting for hydrogen production and photocatalytic degradation of pollutants are summarized.Firstly,we briefly describe the molecular structures,physicochemical properties,and synthetic strategies for CTF/graphene hybrid-based photocatalysts including solution mixing method,in-situ polymerization method and sol-gel method.We further assess the impact of different preparation methods on the structure,morphology,and interacting model between CTF and graphene in CTF/graphene hybrids.Following the various preparation process for CTF/graphene hybrid-based photocatalysts,these methods are analyzed and compared regarding their merits and demerits.Secondly,the functions of CTF/graphene hybrid-based photocatalysts obtained from different synthesis approaches that enhance the catalytic activity for photocataLytic hydrogen evolution and photocatalytic degradation of pollutants are discussed from the three aspects of light harvesting,charge separation and transfer,and surface catalysis.Particular focus has been placed on the catalytic mechanisms of CTF/graphene hybridbased photocatalysts for enhanced photocatalytic hydrogen evolution and improved photocatalytic degradation of pollutants.Then the rational manipulation of selection and building units of CTF,connecting bonds between CTF and graphene,dimensions and pore structures of CTF/graphene hybrids in design of CTF/graphene hybrid-based photocatalysts is discussed,aiming to inspire critical thinking about the effective strategies for modification of photocatalysts rather than the development of novel materials.In the end,the challenges and some future trends of CTF/graphene hybrids as advanced photocatalysts are also discussed from three aspects:catalysts design,performance stability and reaction mechanism.The approaches offer potential solutions to address the challenges of largescale production,catalyst activity and stability in the further research and development of new types of metal-free hybrid photocatalysts with high efficiency.
