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
With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such ...With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such issues, various investigations on the removal of antibiotics have been undertaken. Photocatalysis has received tremendous attention owing to its great potential in removing antibiotics from aqueous solutions via a green, economic, and effective process. However, such a technology employing traditional photocatalysts suffers from major drawbacks such as light absorption being restricted to the UV spectrum only and fast charge recombination. To overcome these issues, considerable effort has been directed towards the development of advanced visible light-driven photocatalysts. This mini review summarises recent research progress in the state-of-the-art design and fabrication of photocatalysts with visible-light response for photocatalytic degradation of antibiotic wastewater. Such design strategies involve the doping of metal and non-metal into ultraviolet light-driven photocatalysts, development of new semiconductor photocatalysts, construction of heterojunction photocatalysts, and fabrication of surface plasmon resonance-enhanced photocatalytic systems. Additionally, some perspectives on the challenges and future developments in the area of photocatalytic degradation of antibiotics are provided.展开更多
A novel visible-light-responding InVO4-Cu2O-TiO2 ternary nanoheterostructure was designed on the basis of the strategy of energy gap engineering and prepared through ordinary wet chemistry methods. The as-prepared nan...A novel visible-light-responding InVO4-Cu2O-TiO2 ternary nanoheterostructure was designed on the basis of the strategy of energy gap engineering and prepared through ordinary wet chemistry methods. The as-prepared nanoheterostructure was characterized by X-ray powder diffraction(XRD), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM) and diffuse reflectance ultraviolet-visible spectroscopy(UV-vis/DRS). The TEM and HRTEM images of 10%InVO4-40%Cu2O-50%TiO2 confirm the formation of nanoheterostructures resulting from contact of the nanosized TiO2, Cu2O and InVO4 in the size of 5–20 nm in diameter. The InVO4-Cu2O-TiO2 nanoheterostructure, when compared with TiO2, Cu2O, InVO4, InVO4-TiO2 and Cu2O-TiO2, shows significant enhancement in the photocatalytic performance for the degradation of methyl orange(MO) under visible-light irradiation. With a 9 W energy-saving fluorescent lamp as the visible-light source, the MO degradation rate of 10%InVO4-40%Cu2O-50%TiO2 reaches close to 90% during 5 h, and the photocatalytic efficiency is maintained at over 90% after six cycles. This may be mainly ascribed to the matched bandgap configurations of TiO2, Cu2O and InVO4, and the formations of two p-n junctions by the p-type semiconductor Cu2O with the n-type semiconductors TiO2 and InVO4, all of which favor spatial photogenerated charge carrier separation. The X-ray photoelectron spectroscopy(XPS) characterization for the used 10%InVO4-40%Cu2O-50%TiO2 reveals that only a small shakeup satellite peak appears for Cu(II) species, implying bearable photocorrosion of Cu2O. This work could provide new insight into the design and preparation of novel visible-light-responding semiconductor composites.展开更多
Constructing Z-scheme heterojunction to improve the separation efficiency of photogenerated carriers of photocatalysts has gained extensive attention.In this work,we fabricated a novel Z-scheme MoO3/Bi2O4 heterojuncti...Constructing Z-scheme heterojunction to improve the separation efficiency of photogenerated carriers of photocatalysts has gained extensive attention.In this work,we fabricated a novel Z-scheme MoO3/Bi2O4 heterojunction photocatalyst by a hydrothermal method.XPS analysis results indicated that strong interaction between MoO3 and Bi2O4 is generated,which contributes to charge transfer and separation of the photogenerated carriers.This was confirmed by photoluminescence(PL)and electrochemical impedance spectroscopy(EIS)tests.The photocatalytic performance of the as-synthesized photocatalysts was evaluated by degrading rhodamine B(RhB)in aqueous solution under visible light irradiation,showing that 15%MoO3/Bi2O4(15-MB)composite exhibited the highest photocatalytic activity,which is 2 times higher than that of Bi2O4.Besides,the heterojunction photocatalyst can keep good photocatalytic activity and stability after five recycles.Trapping experiments demonstrated that the dominant active radicals in photocatalytic reactions are superoxide radical( O2-)and holes(h+),indicating that the 15-MB composite is a Z-scheme photocatalyst.Finally,the mechanism of the Z-scheme MoO3/Bi2O4 composite for photo-degrading RhB in aqueous solution is proposed.This work provides a promising strategy for designing Bi-based Z-scheme heterojunction photocatalysts for highly efficient removal of environmental pollutants.展开更多
Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via ...Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via in situ growth of bismuth oxyiodide(BiOI)nanoplates on the surface of g‐C3N4 nanosheets.The crystal phase,microstructure,optical absorption and textural properties of the synthesized photocatalysts were analyzed by X‐ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),ultraviolet‐visible(UV‐vis)diffuse reflectance spectroscopy(DRS),and nitrogen adsorption‐desorption isotherm measurements.The BiOI/g‐C3N4 nanosheet composite showed high activity and recyclability for the photodegradation of the target pollutant rhodamine B(RhB).The conversion of RhB(20 mg L?1)by the photocatalyst was nearly 100%after 50 min under visible‐light irradiation.The high photoactivity of the BiOI/g‐C3N4 nanosheet composite can be attributed to the enhanced visible‐light absorption of the g‐C3N4 nanosheets sensitized by BiOI nanoplates as well as the high charge separation efficiency obtained by the establishment of an internal electric field between the n‐type g‐C3N4 and p‐type BiOI.Based on the characterization and experimental results,a double‐transfer mechanism of the photoinduced electrons in the BiOI/g‐C3N4 nanosheet composite was proposed to explain its activity.This work represents a new strategy to understand and realize the design and synthesis of g‐C3N4 nanosheet‐based heterojunctions that display highly efficient charge separation and transfer.展开更多
Mesoporous FeVO4 nanorods were successfully synthesized by calcining the precursor Fe- VO4·1.1H2O nanorods, which were obtained via a simple hydrothermal method in the presence of a reactable metal-ion-containing...Mesoporous FeVO4 nanorods were successfully synthesized by calcining the precursor Fe- VO4·1.1H2O nanorods, which were obtained via a simple hydrothermal method in the presence of a reactable metal-ion-containing ionic liquid, 1-octyl-3-methylimidazolium tetrachloride ferrate(III)([Omim]FeCl4). The structure and morphology of the prepared samples were examined using various characterization techniques. During the synthetic process,[Omim]FeCl4 acted as the solvent, reactant, and capping agent simultaneously. Moreover, the porous FeVO4 nanorods as the heterogeneous photo-Fenton-like semiconductor catalyst for the degradation of tetracycline and rhodamine B under visible light irradiation exhibited excellent photocatalytic activity. This excellent photocatalytic activity of the porous FeVO4 nanorods can be attributed to the synergistic effect of their high electron-hole pair separation rate, suitable band gap structure, and large specific surface area. The possible photocatalytic degradation mechanism of FeVO4/H2O2 photocatalytic systems was also discussed in detail.展开更多
Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduct...Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduction band of Ag3PO4.In this study,A composite consisting of Bi2WO6nanosheets and Ag3PO4was developed to curb recombination of charge carriers and enhance the activity and stability of the catalyst.Formation of a Ag3PO4/Bi2WO6composite was confirmed using X‐ray diffraction,energy‐dispersive X‐ray spectroscopy,and X‐ray photoelectron spectroscopy.Photoluminescence spectroscopy provided convincing evidence that compositing Bi2WO6with Ag3PO4effectively reduced photocorrosion of Ag3PO4.The Ag3PO4/Bi2WO6composite gave a high photocatalytic performance in photodegradation of methylene blue.A degradation rate of0.61min?1was achieved;this is1.3and6.0times higher than those achieved using Ag3PO4(0.47min?1)and Bi2WO6(0.10min?1),respectively.Reactive species trapping experiments using the Ag3PO4/Bi2WO6composite showed that holes,?OH,and?O2?all played specific roles in the photodegradation process.The photocatalytic mechanism was investigated and a Z‐scheme was proposed as a plausible mechanism.展开更多
The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflecta...The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.展开更多
Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging...Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light.Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years,it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method.Therefore,developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment.In this work,we successfully prepared porous Bi2O3 in large scale via etching commercial Bi Sn powders,followed by thermal treatment with air.The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue.Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species,such as O2^-·and·OH,which effectively degraded MB.展开更多
Magnetically separable bismuth ferrite(BiFeO3)nanoparticles were fabricated by a citrate self‐combustion method and coated with titanium dioxide(TiO2)by hydrolysis of titanium butoxide(Ti(OBu)4)to form BiFeO3@TiO2cor...Magnetically separable bismuth ferrite(BiFeO3)nanoparticles were fabricated by a citrate self‐combustion method and coated with titanium dioxide(TiO2)by hydrolysis of titanium butoxide(Ti(OBu)4)to form BiFeO3@TiO2core-shell nanocomposites with different mass ratios of TiO2to BiFeO3.The photocatalytic performance of the catalysts was comprehensively investigated via photocatalytic oxidation of methyl violet(MV)under both ultraviolet and visible‐light irradiation.The BiFeO3@TiO2samples exhibited better photocatalytic performance than either BiFeO3or TiO2alone,and a BiFeO3@TiO2sample with a mass ratio of1:1and TiO2shell thickness of50-100nm showed the highest photo‐oxidation activity of the catalysts.The enhanced photocatalytic activity was ascribed to the formation of a p‐n junction of BiFeO3and TiO2with high charge separation efficiency as well as strong light absorption ability.Photoelectrochemical Mott-Schottky(MS)measurements revealed that both the charge carrier transportation and donor density of BiFeO3were markedly enhanced after introduction of TiO2.The mechanism of MV degradation is mainly attributed to hydroxyl radicals and photogenerated electrons based on energy band theory and the formation of an internal electrostatic field.In addition,the unique core-shell structure of BiFeO3@TiO2also promotes charge transfer at the BiFeO3/TiO2interface by increasing the contact area between BiFeO3and TiO2.Finally,the photocatalytic activity of BiFeO3@TiO2was further confirmed by degradation of other industrial dyes under visible‐light irradiation.展开更多
g-C3N4 is a hot visible light photocatalyst. However, the fast recombination of photogenerated electron- hole pairs leads to unsatisfactory photocatalytic efficiencies. In this study, Mg/O co-decorated amorphous carbo...g-C3N4 is a hot visible light photocatalyst. However, the fast recombination of photogenerated electron- hole pairs leads to unsatisfactory photocatalytic efficiencies. In this study, Mg/O co-decorated amorphous carbon nitride (labeled as MgO-CN) with a unique electronic structure was designed and prepared via a combined experimental and theoretical approach. The results showed that the MgO-CN exhibited an increased light absorption ability and promoted charge separation efficiency. The Mg and O co-decoration created a unique structure that could generate localized electrons around O atoms and enhance the reactant activation capacities via the C→O←Mg route. This could dramatically promote the O2 molecule activation on the catalyst surface to generate reactive species (?O2 –/?OH). The optimized MgO-CN exhibited a high photocatalytic activity for the degradation of tetracycline hydrochloride in water, which was five times higher than that of pristine g-C3N4. The present work could provide a new strategy for modifying the electronic structure of g-C3N4 and enhancing its performance for environmental applications.展开更多
Photocatalyst CoPcS/TiO2 was prepared by sol-gel method. Composite CoPcS/TiO2/K2Ti4O9 was prepared by dipping. It was incandesced at various temperatures and modification effect was compared. The results showed that o...Photocatalyst CoPcS/TiO2 was prepared by sol-gel method. Composite CoPcS/TiO2/K2Ti4O9 was prepared by dipping. It was incandesced at various temperatures and modification effect was compared. The results showed that optical absorption of sample incandesce at 423K occurred significant red-shift. Light absorption width extended from ultraviolet region to visible region, especially there was an intensive absorption between 600 nm and 680 nm. X-ray diffraction spectrogram showed that TiO2 in sample still maintained anatase crystal form. Under the illumination of visible light, photocatalysis degradation experiment was taken with Eosin B as simulated pollutants. Decoloration rate of Eosin B was much improved. The rate can reach 80% in 300 minutes.展开更多
Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets and then heating the nanosheets with ure...Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets and then heating the nanosheets with urea. The resulting samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and N2 adsorption-desorption measurements. It was found that N-doping resulted in a much higher thermostability of the layered structure, intrinsic bandgap narrowing and a visible light response. The doped nitrogen atoms were mainly located in the interstitial sites of TiNbOs- lamellae and chemically bound to hydrogen ions. Compared with N-doped HTiNbOs, N-doped HTiNbO5 nanosheets had a much larger specific surface area and richer mesoporosity due to fee rather loose and irregular arrangement of fitanoniobate nanosheets. Both N-doped layered HTiNbOs and HTiNbO5 nanosheets showed a very high visible-light photocatalytic activity for the degradation of rhodamine B (RhB) aqueous solution. Moreover, due to the considerably larger surface area, richer mesoporosity and stronger acidity, N-doped HTiNbO5 nanosheets had an even higher activity than N-doped HTiNbOs, although the latter had a stronger absorption in the visible region. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. The effect of photosensitization was insignificant and RhB was degraded mainly via the typical photocatalytic reaction routes. Two different reaction routes for the photodegradation of RhB under visible light irradiation over N-doped HTiNbO5 nanosheets have been proposed. The present method can be extended to a large number of layered metal oxides that have the characteristics of intercalation and exfoliation, thus providing new opportunities for the fabrication of highly effective and potentially practical visible-light photocatalysts.展开更多
Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitiz...Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitized TiO2 composite used to photocatalytically degrade pollutants.In this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2 composites were prepared using a hydrothermal method.The morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence spectroscopy.The visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model reaction.Results showed that dye-sensitized TiO2 samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2 samples.The double dye-sensitized (or co-sensitized) TiO2 composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2 composite.The electron transfer processes of single and double dye-sensitized TiO2 composites were illustrated according to band theory.展开更多
As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, whic...As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, which only accounts for less than 5% of sunlight. Herein, we reported a TiO2/H2O2-based thermally-assisted photocatalytic process that allows lignin to be efficiently degraded under visible/near-infrared light at an elevated temperature. Adsorption of H2O2 on TiO2 nanoparticles and an increase of temperature facilitate the production and separation of charge carriers under near-infrared and visible light irradiation, accelerate carrier transfer at the TiO2-electrolyte interface and promote the production of hydroxyl radicals, A higher level of H2O2 addition results in an increased degradation rate of lignin,while the optimal temperature for the thermally-assisted photodegradation of lignin is 70℃. A charge carrier excitation and transfer process was proposed for the TiO2/H2O2, thermally-assisted photocatalytic process. This work describes a new method for the photodegradation of organic pollutants,such as residual lignin in paper mill effluent, using wide band gap semiconductors under visible and near-infrared light irradiation.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
Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The ob...Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb(II) and Cr(VI) into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords: 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst展开更多
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supported by the National Natural Science Foundation of China(21421001,21276116,21477050,21301076,21303074)Natural Science Foundation of Jiangsu Province(BK20140530,BK20150482)+5 种基金China Postdoctoral Science Foundation(2015M570409)Chinese-German Cooperation Research Project(GZ1091)Program for High-Level Innovative and Entrepreneurial Talents in Jiangsu ProvinceProgram for New Century Excellent Talents in University(NCET-13-0835)Henry Fok Education Foundation(141068)Six Talents Peak Project in Jiangsu Province(XCL-025)~~
文摘With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such issues, various investigations on the removal of antibiotics have been undertaken. Photocatalysis has received tremendous attention owing to its great potential in removing antibiotics from aqueous solutions via a green, economic, and effective process. However, such a technology employing traditional photocatalysts suffers from major drawbacks such as light absorption being restricted to the UV spectrum only and fast charge recombination. To overcome these issues, considerable effort has been directed towards the development of advanced visible light-driven photocatalysts. This mini review summarises recent research progress in the state-of-the-art design and fabrication of photocatalysts with visible-light response for photocatalytic degradation of antibiotic wastewater. Such design strategies involve the doping of metal and non-metal into ultraviolet light-driven photocatalysts, development of new semiconductor photocatalysts, construction of heterojunction photocatalysts, and fabrication of surface plasmon resonance-enhanced photocatalytic systems. Additionally, some perspectives on the challenges and future developments in the area of photocatalytic degradation of antibiotics are provided.
基金supported by the National Natural Science Foundation of China(21171174)Provincial Natural Science Foundation of Hunan(09JJ3024)Provincial Environmental Science and Technology Foundation of Hunan~~
文摘A novel visible-light-responding InVO4-Cu2O-TiO2 ternary nanoheterostructure was designed on the basis of the strategy of energy gap engineering and prepared through ordinary wet chemistry methods. The as-prepared nanoheterostructure was characterized by X-ray powder diffraction(XRD), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM) and diffuse reflectance ultraviolet-visible spectroscopy(UV-vis/DRS). The TEM and HRTEM images of 10%InVO4-40%Cu2O-50%TiO2 confirm the formation of nanoheterostructures resulting from contact of the nanosized TiO2, Cu2O and InVO4 in the size of 5–20 nm in diameter. The InVO4-Cu2O-TiO2 nanoheterostructure, when compared with TiO2, Cu2O, InVO4, InVO4-TiO2 and Cu2O-TiO2, shows significant enhancement in the photocatalytic performance for the degradation of methyl orange(MO) under visible-light irradiation. With a 9 W energy-saving fluorescent lamp as the visible-light source, the MO degradation rate of 10%InVO4-40%Cu2O-50%TiO2 reaches close to 90% during 5 h, and the photocatalytic efficiency is maintained at over 90% after six cycles. This may be mainly ascribed to the matched bandgap configurations of TiO2, Cu2O and InVO4, and the formations of two p-n junctions by the p-type semiconductor Cu2O with the n-type semiconductors TiO2 and InVO4, all of which favor spatial photogenerated charge carrier separation. The X-ray photoelectron spectroscopy(XPS) characterization for the used 10%InVO4-40%Cu2O-50%TiO2 reveals that only a small shakeup satellite peak appears for Cu(II) species, implying bearable photocorrosion of Cu2O. This work could provide new insight into the design and preparation of novel visible-light-responding semiconductor composites.
基金supported by the Natural Science Foundation of Hubei Province(2016CFA078)the National Natural Science Foundation of China(51472194)~~
文摘Constructing Z-scheme heterojunction to improve the separation efficiency of photogenerated carriers of photocatalysts has gained extensive attention.In this work,we fabricated a novel Z-scheme MoO3/Bi2O4 heterojunction photocatalyst by a hydrothermal method.XPS analysis results indicated that strong interaction between MoO3 and Bi2O4 is generated,which contributes to charge transfer and separation of the photogenerated carriers.This was confirmed by photoluminescence(PL)and electrochemical impedance spectroscopy(EIS)tests.The photocatalytic performance of the as-synthesized photocatalysts was evaluated by degrading rhodamine B(RhB)in aqueous solution under visible light irradiation,showing that 15%MoO3/Bi2O4(15-MB)composite exhibited the highest photocatalytic activity,which is 2 times higher than that of Bi2O4.Besides,the heterojunction photocatalyst can keep good photocatalytic activity and stability after five recycles.Trapping experiments demonstrated that the dominant active radicals in photocatalytic reactions are superoxide radical( O2-)and holes(h+),indicating that the 15-MB composite is a Z-scheme photocatalyst.Finally,the mechanism of the Z-scheme MoO3/Bi2O4 composite for photo-degrading RhB in aqueous solution is proposed.This work provides a promising strategy for designing Bi-based Z-scheme heterojunction photocatalysts for highly efficient removal of environmental pollutants.
文摘Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via in situ growth of bismuth oxyiodide(BiOI)nanoplates on the surface of g‐C3N4 nanosheets.The crystal phase,microstructure,optical absorption and textural properties of the synthesized photocatalysts were analyzed by X‐ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),ultraviolet‐visible(UV‐vis)diffuse reflectance spectroscopy(DRS),and nitrogen adsorption‐desorption isotherm measurements.The BiOI/g‐C3N4 nanosheet composite showed high activity and recyclability for the photodegradation of the target pollutant rhodamine B(RhB).The conversion of RhB(20 mg L?1)by the photocatalyst was nearly 100%after 50 min under visible‐light irradiation.The high photoactivity of the BiOI/g‐C3N4 nanosheet composite can be attributed to the enhanced visible‐light absorption of the g‐C3N4 nanosheets sensitized by BiOI nanoplates as well as the high charge separation efficiency obtained by the establishment of an internal electric field between the n‐type g‐C3N4 and p‐type BiOI.Based on the characterization and experimental results,a double‐transfer mechanism of the photoinduced electrons in the BiOI/g‐C3N4 nanosheet composite was proposed to explain its activity.This work represents a new strategy to understand and realize the design and synthesis of g‐C3N4 nanosheet‐based heterojunctions that display highly efficient charge separation and transfer.
基金financially supported by the National Natural Science Foundation of China(21471069,21476098,and 21576123)Jiangsu University Scientific Research Funding(11JDG0146)~~
文摘Mesoporous FeVO4 nanorods were successfully synthesized by calcining the precursor Fe- VO4·1.1H2O nanorods, which were obtained via a simple hydrothermal method in the presence of a reactable metal-ion-containing ionic liquid, 1-octyl-3-methylimidazolium tetrachloride ferrate(III)([Omim]FeCl4). The structure and morphology of the prepared samples were examined using various characterization techniques. During the synthetic process,[Omim]FeCl4 acted as the solvent, reactant, and capping agent simultaneously. Moreover, the porous FeVO4 nanorods as the heterogeneous photo-Fenton-like semiconductor catalyst for the degradation of tetracycline and rhodamine B under visible light irradiation exhibited excellent photocatalytic activity. This excellent photocatalytic activity of the porous FeVO4 nanorods can be attributed to the synergistic effect of their high electron-hole pair separation rate, suitable band gap structure, and large specific surface area. The possible photocatalytic degradation mechanism of FeVO4/H2O2 photocatalytic systems was also discussed in detail.
基金supported by the National Natural Science Foundation of China(51572103,51502106)the Foundation for Young Talents in College of Anhui Province(gxyqZD201751)~~
文摘Ag3PO4has good potential for use in photocatalytic degradation of organic contaminants.However,the activity and stability of Ag3PO4is hard to sustain because of photocorrosion and the positive potential of the conduction band of Ag3PO4.In this study,A composite consisting of Bi2WO6nanosheets and Ag3PO4was developed to curb recombination of charge carriers and enhance the activity and stability of the catalyst.Formation of a Ag3PO4/Bi2WO6composite was confirmed using X‐ray diffraction,energy‐dispersive X‐ray spectroscopy,and X‐ray photoelectron spectroscopy.Photoluminescence spectroscopy provided convincing evidence that compositing Bi2WO6with Ag3PO4effectively reduced photocorrosion of Ag3PO4.The Ag3PO4/Bi2WO6composite gave a high photocatalytic performance in photodegradation of methylene blue.A degradation rate of0.61min?1was achieved;this is1.3and6.0times higher than those achieved using Ag3PO4(0.47min?1)and Bi2WO6(0.10min?1),respectively.Reactive species trapping experiments using the Ag3PO4/Bi2WO6composite showed that holes,?OH,and?O2?all played specific roles in the photodegradation process.The photocatalytic mechanism was investigated and a Z‐scheme was proposed as a plausible mechanism.
基金Project(8451063201001261) supported by the Guangdong Natural Science Fund Committee,ChinaProject(LYM08022) supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong,China+1 种基金Project (2007A032400001, 2008A030202010) supported by the Scientific and Technological Planning of Guangdong Province,ChinaProject(216113132) supported by the Scientific Research Cultivation and Innovation Fund, Jinan University,China
文摘The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.
基金the National Natural Science Foundation of China(No.51801235,No.11875258,No.11505187,No.51374255,No.51802356,No.51572299,and No.41701359)the Innovation-Driven Project of Central South University(No.2018CX004)+4 种基金the Start-up Funding of Central South University(No.502045005)the Fundamental Research Funds for the Central Universities(No.WK2310000066,No.WK2060190081)Posdoctoral Science Foundation of China(No.2019M652797)Central South University Postdoctoral Research Opening Fundthe Fundamental Research Funds for the Central Universities of Central South University(No.2018zzts402)。
文摘Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light.Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years,it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method.Therefore,developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment.In this work,we successfully prepared porous Bi2O3 in large scale via etching commercial Bi Sn powders,followed by thermal treatment with air.The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue.Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species,such as O2^-·and·OH,which effectively degraded MB.
基金supported by the Australian Research Council(ARC DP150103026)the National Natural Science Foundation of China(51278242)~~
文摘Magnetically separable bismuth ferrite(BiFeO3)nanoparticles were fabricated by a citrate self‐combustion method and coated with titanium dioxide(TiO2)by hydrolysis of titanium butoxide(Ti(OBu)4)to form BiFeO3@TiO2core-shell nanocomposites with different mass ratios of TiO2to BiFeO3.The photocatalytic performance of the catalysts was comprehensively investigated via photocatalytic oxidation of methyl violet(MV)under both ultraviolet and visible‐light irradiation.The BiFeO3@TiO2samples exhibited better photocatalytic performance than either BiFeO3or TiO2alone,and a BiFeO3@TiO2sample with a mass ratio of1:1and TiO2shell thickness of50-100nm showed the highest photo‐oxidation activity of the catalysts.The enhanced photocatalytic activity was ascribed to the formation of a p‐n junction of BiFeO3and TiO2with high charge separation efficiency as well as strong light absorption ability.Photoelectrochemical Mott-Schottky(MS)measurements revealed that both the charge carrier transportation and donor density of BiFeO3were markedly enhanced after introduction of TiO2.The mechanism of MV degradation is mainly attributed to hydroxyl radicals and photogenerated electrons based on energy band theory and the formation of an internal electrostatic field.In addition,the unique core-shell structure of BiFeO3@TiO2also promotes charge transfer at the BiFeO3/TiO2interface by increasing the contact area between BiFeO3and TiO2.Finally,the photocatalytic activity of BiFeO3@TiO2was further confirmed by degradation of other industrial dyes under visible‐light irradiation.
基金supported by the Specialized Innovation of Social and People’s Livelihood in Chongqing(cstc2016shmszx20012)Converting Outstanding Achievements of University-Funded Projects of Chongqing(KJZH17122)+3 种基金the National Natural Science Foundation of China(5160080705)the Key Laboratory Open Project from Chongqing Technology and Business University(1556036)Innovative Research Project from Chongqing Technology and Business University(yjscxx2016-060-34)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ130704)~~
文摘g-C3N4 is a hot visible light photocatalyst. However, the fast recombination of photogenerated electron- hole pairs leads to unsatisfactory photocatalytic efficiencies. In this study, Mg/O co-decorated amorphous carbon nitride (labeled as MgO-CN) with a unique electronic structure was designed and prepared via a combined experimental and theoretical approach. The results showed that the MgO-CN exhibited an increased light absorption ability and promoted charge separation efficiency. The Mg and O co-decoration created a unique structure that could generate localized electrons around O atoms and enhance the reactant activation capacities via the C→O←Mg route. This could dramatically promote the O2 molecule activation on the catalyst surface to generate reactive species (?O2 –/?OH). The optimized MgO-CN exhibited a high photocatalytic activity for the degradation of tetracycline hydrochloride in water, which was five times higher than that of pristine g-C3N4. The present work could provide a new strategy for modifying the electronic structure of g-C3N4 and enhancing its performance for environmental applications.
基金Acknowledgements: This project is supported by the fund of the Plan of Postgraduate Scientific Research Innovation of Jiangsu Province (No. CX07B_175z) and the Natural Science Foundation of Henan Province (No. 0624720029).
文摘Photocatalyst CoPcS/TiO2 was prepared by sol-gel method. Composite CoPcS/TiO2/K2Ti4O9 was prepared by dipping. It was incandesced at various temperatures and modification effect was compared. The results showed that optical absorption of sample incandesce at 423K occurred significant red-shift. Light absorption width extended from ultraviolet region to visible region, especially there was an intensive absorption between 600 nm and 680 nm. X-ray diffraction spectrogram showed that TiO2 in sample still maintained anatase crystal form. Under the illumination of visible light, photocatalysis degradation experiment was taken with Eosin B as simulated pollutants. Decoloration rate of Eosin B was much improved. The rate can reach 80% in 300 minutes.
基金Acknowledgements The authors greatly appreciate the financial support of the National Natural Science Foundation of China (Grant Nos. 21073084 and 20773065), the National Basic Research Program (973 Project) (Grant No. 2007CB936302) and the Modern Analysis Center of Nanjing University.
文摘Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets and then heating the nanosheets with urea. The resulting samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and N2 adsorption-desorption measurements. It was found that N-doping resulted in a much higher thermostability of the layered structure, intrinsic bandgap narrowing and a visible light response. The doped nitrogen atoms were mainly located in the interstitial sites of TiNbOs- lamellae and chemically bound to hydrogen ions. Compared with N-doped HTiNbOs, N-doped HTiNbO5 nanosheets had a much larger specific surface area and richer mesoporosity due to fee rather loose and irregular arrangement of fitanoniobate nanosheets. Both N-doped layered HTiNbOs and HTiNbO5 nanosheets showed a very high visible-light photocatalytic activity for the degradation of rhodamine B (RhB) aqueous solution. Moreover, due to the considerably larger surface area, richer mesoporosity and stronger acidity, N-doped HTiNbO5 nanosheets had an even higher activity than N-doped HTiNbOs, although the latter had a stronger absorption in the visible region. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. The effect of photosensitization was insignificant and RhB was degraded mainly via the typical photocatalytic reaction routes. Two different reaction routes for the photodegradation of RhB under visible light irradiation over N-doped HTiNbO5 nanosheets have been proposed. The present method can be extended to a large number of layered metal oxides that have the characteristics of intercalation and exfoliation, thus providing new opportunities for the fabrication of highly effective and potentially practical visible-light photocatalysts.
基金supported by the National Natural Science Foundation of China (20407002)National Basic Research Program of China (2002CB410802)Special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control
文摘Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitized TiO2 composite used to photocatalytically degrade pollutants.In this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2 composites were prepared using a hydrothermal method.The morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence spectroscopy.The visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model reaction.Results showed that dye-sensitized TiO2 samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2 samples.The double dye-sensitized (or co-sensitized) TiO2 composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2 composite.The electron transfer processes of single and double dye-sensitized TiO2 composites were illustrated according to band theory.
基金funded by the National Natural Science Foundation of China (31270625)
文摘As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, which only accounts for less than 5% of sunlight. Herein, we reported a TiO2/H2O2-based thermally-assisted photocatalytic process that allows lignin to be efficiently degraded under visible/near-infrared light at an elevated temperature. Adsorption of H2O2 on TiO2 nanoparticles and an increase of temperature facilitate the production and separation of charge carriers under near-infrared and visible light irradiation, accelerate carrier transfer at the TiO2-electrolyte interface and promote the production of hydroxyl radicals, A higher level of H2O2 addition results in an increased degradation rate of lignin,while the optimal temperature for the thermally-assisted photodegradation of lignin is 70℃. A charge carrier excitation and transfer process was proposed for the TiO2/H2O2, thermally-assisted photocatalytic process. This work describes a new method for the photodegradation of organic pollutants,such as residual lignin in paper mill effluent, using wide band gap semiconductors under visible and near-infrared light irradiation.
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.
基金jointly supported by the National Natural Science Foundation of China(21401190)the Science and Technology Project of Research Foundation of China Postdoctoral Science(2017M612710 and 2016M592519)+2 种基金Shenzhen Peacock Plan(827-000059,827-000113 and KQTD2016053112042971)the Science and Technology Planning Project of Guangdong Province(2016B050501005)the Educational Commission of Guangdong Province(2016KCXTD006 and 2016KSTCX126)
文摘Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb(II) and Cr(VI) into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords: 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst