The photoreduction of greenhouse gas CO_(2) using photocatalytic technologies not only benefits en-vironmental remediation but also facilitates the production of raw materials for chemicals.Howev-er,the efficiency of ...The photoreduction of greenhouse gas CO_(2) using photocatalytic technologies not only benefits en-vironmental remediation but also facilitates the production of raw materials for chemicals.Howev-er,the efficiency of CO_(2) photoreduction remains generally low due to the challenging activation of CO_(2) and the limited light absorption and separation of charge.Defect engineering of catalysts rep-resents a pivotal strategy to enhance the photocatalytic activity for CO_(2),with most research on met-al oxide catalysts focusing on the creation of anionic vacancies.The exploration of metal vacancies and their effects,however,is still underexplored.In this study,we prepared an In2O3 catalyst with indium vacancies(VIn)through defect engineering for CO_(2) photoreduction.Experimental and theo-retical calculations results demonstrate that VIn not only facilitate light absorption and charge sepa-ration in the catalyst but also enhance CO_(2) adsorption and reduce the energy barrier for the for-mation of the key intermediate*COOH during CO_(2) reduction.Through metal vacancy engineering,the activity of the catalyst was 7.4 times,reaching an outstanding rate of 841.32μmol g(-1)h^(-1).This work unveils the mechanism of metal vacancies in CO_(2) photoreduction and provides theoretical guidance for the development of novel CO_(2) photoreduction catalysts.展开更多
The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,e...Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,existing reviews primarily focus on specific oxidation reactions,such as oxidative organic synthesis and water remediation,often neglecting recent advancements in plastic upgrading,biomass conversion,and H_(2)O_(2)production,and failing to provide an in-depth discussion of catalytic mechanisms.This review addresses these gaps by offering a comprehensive overview of recent advancements in dual-channel redox reactions for photocatalytic H_(2)-evolution and waste photoreforming.It highlights waste-to-wealth design concepts,examines the challenges,advantages and diverse applications of dual-channel photocatalytic reactions,including photoreforming of biomass,alcohol,amine,plastic waste,organic pollutants,and H_(2)O_(2)production.Emphasizing improvement strategies and exploration of catalytic mechanisms,it includes advanced in-situ characterization,spin capture experiments,and DFT calculations.By identifying challenges and future directions in this field,this review provides valuable insights for designing innovative dual-channel photocatalytic systems.展开更多
Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has...Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.展开更多
Ternary Ag/AgC l/BiO IO3 composite photocatalysts are prepared by a facile method. Enhanced visible-light absorption and charge carrier separation are achieved after the introduction of Ag/AgC l particles into BiO IO3...Ternary Ag/AgC l/BiO IO3 composite photocatalysts are prepared by a facile method. Enhanced visible-light absorption and charge carrier separation are achieved after the introduction of Ag/AgC l particles into BiO IO3 systems,as revealed by ultraviolet-visible diffuse-reflectance spectrometry,photocurrent response and electrochemical impedance spectroscopy. The Ag/AgC l/BiO IO3 composites are applied to the visible-light photocatalytic oxidization of NO in air and exhibit an enhanced activity for NO removal in comparison with Ag/AgC l and pure BiO IO3. A possible photocatalytic mechanism for Ag/AgC l/BiO IO3 is proposed,which is related to the surface plasmon resonance effects of Ag metal and the effective carrier separation ability of BiO IO3. This work provides insight into the design and preparation of BiO IO3-based materials with enhanced visible-light photocatalysis ability.展开更多
In order to remove nitric oxides （NO） from flue gas, experimental studies on the photocatalytic oxidation （PCO） of NO are carried out in an efficient laboratory-scale reactor. Nano-sized TiO2 particles loading on ...In order to remove nitric oxides （NO） from flue gas, experimental studies on the photocatalytic oxidation （PCO） of NO are carried out in an efficient laboratory-scale reactor. Nano-sized TiO2 particles loading on quartz sand are prepared and used as the photocatalyst. Effects of several key operating parameters on NO conversion are investigated, including operating temperature, NO inlet concentration, oxygen percentage, relative humidity and residence time. The results illustrate that the NO inlet concentration, the oxygen percentage and the relative humidity play an important role in the oxidation of NO. A lower NO inlet concentration and a higher oxygen percentage result in a higher NO conversion efficiency. When the relative humidity is 8%, the maximum value of NO conversion efficiency is achieved. In addition, the operating temperature and the residence time have a little effect on the conversion efficiency of NO.展开更多
Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after th...Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.展开更多
A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious m...A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance.Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated.It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency.With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples,the photocatalytic activities increased first and then decreased.The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene（9.91×10^-3 min^-1）,which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples,respectively.This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system.Thus,ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.展开更多
Black TiO2（B）/anatase bicrystalline TiO2-x nanofibers were synthesized from a porous titanate derivative by calcination in H2, and were characterized using field-emission scanning electron microscopy, Raman spectros...Black TiO2（B）/anatase bicrystalline TiO2-x nanofibers were synthesized from a porous titanate derivative by calcination in H2, and were characterized using field-emission scanning electron microscopy, Raman spectroscopy, N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet-visible diffuse reflection spectroscopy and photoluminescence measurements. Characterization results showed that no Ti3＋ was present on the surface of black bicrystalline TiO2-x and oxygen vacancies were distributed in the bulk of both TiO2（B） and anatase phases. The O/Ti atom stoichiometric ratio of black bicrystalline TiO2-x was estimated to be 1.97 from the difference of mass loss between black bicrystalline TiO2-x and white bicrystalline TiO2 without oxygen vacancies. The photocatalytic activity of black bicrystalline TiO2-x was 4.2 times higher than that of white bicrystalline TiO2 and 10.5 times higher than that of anatase TiOz. The high photocatalytic activity of black bicrystalline TiO2-x was attributed to its effective separation of electrons and holes, which may be related to the effects of both bicrystalline structure and oxygen vacancies. Black bicrystalline TiO2-x also exhibited good photocatalytic activity after recycling ten times. The black bicrystalline TiO2-x nanofibers show potential for use in environmental and energy applications.展开更多
Graphitic carbon nitride（g-C3N4） with efficient photocatalytic activity was synthesized through thermal polymerization of thiourea with the addition of water（CN-W） or ethanol（CN-E） at 550 ℃for 2 h.The physicoch...Graphitic carbon nitride（g-C3N4） with efficient photocatalytic activity was synthesized through thermal polymerization of thiourea with the addition of water（CN-W） or ethanol（CN-E） at 550 ℃for 2 h.The physicochemical properties of the g-C3N4 were investigated by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,photoluminescence spectroscopy,diffuse-reflection spectroscopy,BET and BJH surface area characterization,and elemental analysis.The carbon content was found to have self-doped into the g-C3N4 matrix during the thermal polymerization of thiourea and ethanol.CN-W and CN-E showed considerably enhanced visible-light photocatalytic activity,with NO removal percentages of 37.2%and 48.3%,respectively.Compared with pure g-C3N4,both the short and long lifetimes of the charge carriers in CN-W and CN-E were found to be prolonged.The mechanism of improved visible-light photocatalytic activity was deduced.The present work may provide a facile route to optimize the microstructure of g-C3N4photocatalysts for high-performance environmental and energy applications.展开更多
Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid i...Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid interfacial charge transfer. However,the present preparation methods usually include complicated and multistep procedures,which can cause damage to the hollow nanostructures. In this paper,a facile template-induced synthesis,based on a template-directed deposition and in situ template-sacrificial dissolution,was employed to prepare Ag-modified TiO 2（Ag/TiO 2） hollow octahedra using Ag2 O octahedra as templates and TiF 4 as the precursor. In the synthetic strategy,the shells of TiO 2 hollow octahedra were formed by coating TiO 2 nanoparticles on the surface of Ag2 O templates based on the template-directed deposition. Simultaneously,the Ag2 O templates can be in situ removed by dissolving the Ag2 O octahedral template in HF solution produced via the hydrolysis reaction of TiF 4 in the reaction system. In addition,Ag nanoparticles were deposited on the inside and outside surfaces of TiO 2 shells by effectively using the photosensitive properties of Ag2 O and Ag＋ ions under light irradiation,along with the formation of TiO 2 hollow octahedra. The Ag/TiO 2 hollow octahedra exhibited high photocatalytic activity because of their（1） short diffusion distances between photogenerated electrons and holes because of the thin shells of Ag/TiO 2 hollow octahedral,（2） deposition of Ag nanoparticles on the inside and outside surfaces of TiO 2 shells,and（3） rapid interfacial charge transfer between TiO 2 shells and Ag nanoparticles. This work may also provide new insights into preparing other Ag-modified and hollow nanostructured photocatalysts.展开更多
particle size （5.0 nm）, large specific surface area （213.45 m1 2/g）, and efficient response to broadband light over the entire ultraviolet-visible spectrum with a narrow band gap of 1.84 eV. In addition, TiO2 -18...particle size （5.0 nm）, large specific surface area （213.45 m1 2/g）, and efficient response to broadband light over the entire ultraviolet-visible spectrum with a narrow band gap of 1.84 eV. In addition, TiO2 -180℃ exhibited the optimal reaction rate constant for the degradation of methylene blue （0.08287 mg/（Lmin））, which is six times higher than that of the mixed rutile/anatase phase TiO2 photocatalytic standard P25 （0.01342 mg/（L min））. Furthermore, cycling photodegradation ex-periments confirmed the stability and reusability of this catalyst. The unique physicochemical properties resulting from the low-temperature preparation of TiO2 -180℃, including its broadband visible absorption associated with a high concentration of oxygen vacancies, large surface area, and enriched surface -OH/H2O may be responsible for this excellent photocatalytic performance. The use of as-prepared TiO2 -180℃ for practical applications is expected after further optimization.展开更多
Bismuth oxide/titania, one interfacial composite semiconductor with high photocatalytic activity under solar light, was prepared at low temperature. The structure was characterized by X-ray diffractometry （XRD）, sca...Bismuth oxide/titania, one interfacial composite semiconductor with high photocatalytic activity under solar light, was prepared at low temperature. The structure was characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, brunauer-emmett-teller （BET）, X-ray photoelectron spectroscopy （XPS） and diffuse reflection spectra （DRS）. The results indicate that deposited titania nanoparticles on bismuth oxide surface have micro-nano structure, and this composite material exhibits porosity and increased surface hydroxyl groups. Furthermore, the as-prepared photocatalyst shows higher photocatalytic activity to the degradation of 4-chlorophenol than pure titania or P25 under sunlight.展开更多
In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degr...In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degraded salicylic acid more effectively than did those obtained at pH 3（BOB-3）,but the order of their photocatalytic activities in rhodamine B（RhB） degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation.展开更多
ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered d...ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.展开更多
文摘The photoreduction of greenhouse gas CO_(2) using photocatalytic technologies not only benefits en-vironmental remediation but also facilitates the production of raw materials for chemicals.Howev-er,the efficiency of CO_(2) photoreduction remains generally low due to the challenging activation of CO_(2) and the limited light absorption and separation of charge.Defect engineering of catalysts rep-resents a pivotal strategy to enhance the photocatalytic activity for CO_(2),with most research on met-al oxide catalysts focusing on the creation of anionic vacancies.The exploration of metal vacancies and their effects,however,is still underexplored.In this study,we prepared an In2O3 catalyst with indium vacancies(VIn)through defect engineering for CO_(2) photoreduction.Experimental and theo-retical calculations results demonstrate that VIn not only facilitate light absorption and charge sepa-ration in the catalyst but also enhance CO_(2) adsorption and reduce the energy barrier for the for-mation of the key intermediate*COOH during CO_(2) reduction.Through metal vacancy engineering,the activity of the catalyst was 7.4 times,reaching an outstanding rate of 841.32μmol g(-1)h^(-1).This work unveils the mechanism of metal vacancies in CO_(2) photoreduction and provides theoretical guidance for the development of novel CO_(2) photoreduction catalysts.
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
文摘Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,existing reviews primarily focus on specific oxidation reactions,such as oxidative organic synthesis and water remediation,often neglecting recent advancements in plastic upgrading,biomass conversion,and H_(2)O_(2)production,and failing to provide an in-depth discussion of catalytic mechanisms.This review addresses these gaps by offering a comprehensive overview of recent advancements in dual-channel redox reactions for photocatalytic H_(2)-evolution and waste photoreforming.It highlights waste-to-wealth design concepts,examines the challenges,advantages and diverse applications of dual-channel photocatalytic reactions,including photoreforming of biomass,alcohol,amine,plastic waste,organic pollutants,and H_(2)O_(2)production.Emphasizing improvement strategies and exploration of catalytic mechanisms,it includes advanced in-situ characterization,spin capture experiments,and DFT calculations.By identifying challenges and future directions in this field,this review provides valuable insights for designing innovative dual-channel photocatalytic systems.
文摘Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.
基金supported by the National Natural Science Foundation of China(5147807051108487)the Science and Technology Project from Chongqing Education Commission(KJ1400617)~~
文摘Ternary Ag/AgC l/BiO IO3 composite photocatalysts are prepared by a facile method. Enhanced visible-light absorption and charge carrier separation are achieved after the introduction of Ag/AgC l particles into BiO IO3 systems,as revealed by ultraviolet-visible diffuse-reflectance spectrometry,photocurrent response and electrochemical impedance spectroscopy. The Ag/AgC l/BiO IO3 composites are applied to the visible-light photocatalytic oxidization of NO in air and exhibit an enhanced activity for NO removal in comparison with Ag/AgC l and pure BiO IO3. A possible photocatalytic mechanism for Ag/AgC l/BiO IO3 is proposed,which is related to the surface plasmon resonance effects of Ag metal and the effective carrier separation ability of BiO IO3. This work provides insight into the design and preparation of BiO IO3-based materials with enhanced visible-light photocatalysis ability.
基金The National High Technology Research Program of China (863 Program) (No. 2008AA05Z303)the Science and Technology Program of Jiangsu Province (No. BE2010184)the Environmental Protection Scientific Research Subject of Jiangsu Province (No.201031)
文摘In order to remove nitric oxides （NO） from flue gas, experimental studies on the photocatalytic oxidation （PCO） of NO are carried out in an efficient laboratory-scale reactor. Nano-sized TiO2 particles loading on quartz sand are prepared and used as the photocatalyst. Effects of several key operating parameters on NO conversion are investigated, including operating temperature, NO inlet concentration, oxygen percentage, relative humidity and residence time. The results illustrate that the NO inlet concentration, the oxygen percentage and the relative humidity play an important role in the oxidation of NO. A lower NO inlet concentration and a higher oxygen percentage result in a higher NO conversion efficiency. When the relative humidity is 8%, the maximum value of NO conversion efficiency is achieved. In addition, the operating temperature and the residence time have a little effect on the conversion efficiency of NO.
基金supported by the National Key Research and Development Project (2016YFC0204702)the National Natural Science Foundation of China (51478070, 21501016, 51108487)+2 种基金the Innovative Research Team of Chongqing (CXTDG201602014)the Natural Science Foundation of Chongqing (cstc2016jcyjA0481)Youth Innovation Promotion Association of Chinese Academy of Sciences (2015316)~~
文摘Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.
基金supported by the National Natural Science Foundation of China (51478370)the Engineering and Physical Sciences Research Council of UK–Natural Science Foundation of China (EPSRC-NSFC) International Joint Research Project (51461135005)~~
文摘A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance.Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated.It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency.With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples,the photocatalytic activities increased first and then decreased.The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene（9.91×10^-3 min^-1）,which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples,respectively.This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system.Thus,ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.
基金supported by the National Natural Science Foundation of China(21406118,91434109,91334202)the Highly Educated Talent Foundation of Nanjing Forestry University(GXL2014036)+2 种基金the Doctor Program of Jiangsu ProvinceDistinguished Experts Program of Science and Technology Vice-manager(Enterprise Innovation Job)the Priority Academic Program Development of Jiangsu Higher Education Institutions~~
文摘Black TiO2（B）/anatase bicrystalline TiO2-x nanofibers were synthesized from a porous titanate derivative by calcination in H2, and were characterized using field-emission scanning electron microscopy, Raman spectroscopy, N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet-visible diffuse reflection spectroscopy and photoluminescence measurements. Characterization results showed that no Ti3＋ was present on the surface of black bicrystalline TiO2-x and oxygen vacancies were distributed in the bulk of both TiO2（B） and anatase phases. The O/Ti atom stoichiometric ratio of black bicrystalline TiO2-x was estimated to be 1.97 from the difference of mass loss between black bicrystalline TiO2-x and white bicrystalline TiO2 without oxygen vacancies. The photocatalytic activity of black bicrystalline TiO2-x was 4.2 times higher than that of white bicrystalline TiO2 and 10.5 times higher than that of anatase TiOz. The high photocatalytic activity of black bicrystalline TiO2-x was attributed to its effective separation of electrons and holes, which may be related to the effects of both bicrystalline structure and oxygen vacancies. Black bicrystalline TiO2-x also exhibited good photocatalytic activity after recycling ten times. The black bicrystalline TiO2-x nanofibers show potential for use in environmental and energy applications.
基金supported by the China Postdoctoral Science Foundation Funded Project (2016M592642)Project from Chongqing Education Commission (KJ1600305)+3 种基金Chongqing Basic Science and Advanced Technology Research (cstc2016jcyjAX0003)the Start-up Foundation for Doctors of Chongqing Normal University (15XLB010, 15XLB014)the National Natural Science Foundation of China (51478070, 51108487)the Innovative Research Team of Chongqing (CXTDG201602014)~~
文摘Graphitic carbon nitride（g-C3N4） with efficient photocatalytic activity was synthesized through thermal polymerization of thiourea with the addition of water（CN-W） or ethanol（CN-E） at 550 ℃for 2 h.The physicochemical properties of the g-C3N4 were investigated by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,photoluminescence spectroscopy,diffuse-reflection spectroscopy,BET and BJH surface area characterization,and elemental analysis.The carbon content was found to have self-doped into the g-C3N4 matrix during the thermal polymerization of thiourea and ethanol.CN-W and CN-E showed considerably enhanced visible-light photocatalytic activity,with NO removal percentages of 37.2%and 48.3%,respectively.Compared with pure g-C3N4,both the short and long lifetimes of the charge carriers in CN-W and CN-E were found to be prolonged.The mechanism of improved visible-light photocatalytic activity was deduced.The present work may provide a facile route to optimize the microstructure of g-C3N4photocatalysts for high-performance environmental and energy applications.
基金supported by the National Natural Science Foundation of China(5120839621277107+5 种基金21477094and 51472192)the Program for New Century Excellent Talents in University(NCET-13-0944)the Fundamental Research Funds for the Central Universities(WUT 2014-1a-0032014-VII-037and 2015IB002)~~
文摘Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid interfacial charge transfer. However,the present preparation methods usually include complicated and multistep procedures,which can cause damage to the hollow nanostructures. In this paper,a facile template-induced synthesis,based on a template-directed deposition and in situ template-sacrificial dissolution,was employed to prepare Ag-modified TiO 2（Ag/TiO 2） hollow octahedra using Ag2 O octahedra as templates and TiF 4 as the precursor. In the synthetic strategy,the shells of TiO 2 hollow octahedra were formed by coating TiO 2 nanoparticles on the surface of Ag2 O templates based on the template-directed deposition. Simultaneously,the Ag2 O templates can be in situ removed by dissolving the Ag2 O octahedral template in HF solution produced via the hydrolysis reaction of TiF 4 in the reaction system. In addition,Ag nanoparticles were deposited on the inside and outside surfaces of TiO 2 shells by effectively using the photosensitive properties of Ag2 O and Ag＋ ions under light irradiation,along with the formation of TiO 2 hollow octahedra. The Ag/TiO 2 hollow octahedra exhibited high photocatalytic activity because of their（1） short diffusion distances between photogenerated electrons and holes because of the thin shells of Ag/TiO 2 hollow octahedral,（2） deposition of Ag nanoparticles on the inside and outside surfaces of TiO 2 shells,and（3） rapid interfacial charge transfer between TiO 2 shells and Ag nanoparticles. This work may also provide new insights into preparing other Ag-modified and hollow nanostructured photocatalysts.
基金supported by Teamwork Project Funded by Guangdong Natural Science Foundation(S2013030012842)~~
文摘particle size （5.0 nm）, large specific surface area （213.45 m1 2/g）, and efficient response to broadband light over the entire ultraviolet-visible spectrum with a narrow band gap of 1.84 eV. In addition, TiO2 -180℃ exhibited the optimal reaction rate constant for the degradation of methylene blue （0.08287 mg/（Lmin））, which is six times higher than that of the mixed rutile/anatase phase TiO2 photocatalytic standard P25 （0.01342 mg/（L min））. Furthermore, cycling photodegradation ex-periments confirmed the stability and reusability of this catalyst. The unique physicochemical properties resulting from the low-temperature preparation of TiO2 -180℃, including its broadband visible absorption associated with a high concentration of oxygen vacancies, large surface area, and enriched surface -OH/H2O may be responsible for this excellent photocatalytic performance. The use of as-prepared TiO2 -180℃ for practical applications is expected after further optimization.
基金Project supported by the Scientific Research Foundation of Nanjing University of Information Science and Technology, ChinaProject (2010490511) supported by the Open Foundation of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, China
文摘Bismuth oxide/titania, one interfacial composite semiconductor with high photocatalytic activity under solar light, was prepared at low temperature. The structure was characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, brunauer-emmett-teller （BET）, X-ray photoelectron spectroscopy （XPS） and diffuse reflection spectra （DRS）. The results indicate that deposited titania nanoparticles on bismuth oxide surface have micro-nano structure, and this composite material exhibits porosity and increased surface hydroxyl groups. Furthermore, the as-prepared photocatalyst shows higher photocatalytic activity to the degradation of 4-chlorophenol than pure titania or P25 under sunlight.
基金supported by the National Natural Science Funds for Distinguished Young Scholars(21425728)the National Natural Science Foundation of China(21173093+4 种基金211770482127308821477044)the Key Project of Natural Science Foundation of Hubei Province(2013CFA114)the the Fundamental Research Funds for the Central Universities(CCNU14Z01001 CCNU14KFY002)~~
文摘In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degraded salicylic acid more effectively than did those obtained at pH 3（BOB-3）,but the order of their photocatalytic activities in rhodamine B（RhB） degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation.
基金Project(21306041)supported by the National Natural Science Young Foundation of ChinaProject(21271071)supported by the National Natural Science Foundation of ChinaProject(15A076)supported by the Scientific Research Foundation of Hunan Provincial Education Department of China
文摘ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.
