Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of highly active co-catalysts has proven to be a promising approach for improving photocatalytic activity. Thus far, the most de...Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of highly active co-catalysts has proven to be a promising approach for improving photocatalytic activity. Thus far, the most developed co-catalysts for semiconductor-based photocatalysis are inorganic materials;the employment of a specific organic molecule as a co-catalyst for photocatalytic hydrogen evolution and pollutant photodegradation is rare and still remains a challenging task. Herein, we report on the use of an organic molecule, oxamide (OA), as a novel co-catalyst to enhance electron- hole separation, photocatalytic H2 evolution, and dye degradation over TiO2 nanosheets. OA-modified TiO2 samples were prepared by a wet chemical route and demonstrated improved light absorption in the visible-light region and more efficient charge transport. The photocatalytic performance of H2 evolution from water splitting and rhodamine B (RhB) degradation for an optimal OA-modified TiO2 photocatalyst reached 2.37 mmol g^–1 h^–1 and 1.43 × 10^-2 min^-1, respectively, which were 2.4 and 3.8 times higher than those of pristine TiO2, respectively. A possible mechanism is proposed, in which the specific π-conjugated structure of OA is suggested to play a key role in the enhancement of the charge transfer and catalytic capability of TiO2. This work may provide advanced insight into the development of a variety of metal-free organic molecules as functional co-catalysts for improved solar-to-fuel conversion and environmental remediation.展开更多
A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocom...A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocomposite was characterised by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy,energy-dispersive X-ray spectroscopy（EDX）,UV-visible spectroscopy,transmission electron microscopy（TEM）,N2 gas sorption analysis,X-ray photoelectron spectroscopy（XPS）,and vibrating sample magnetometry.The FT-IR,XRD,EDX and XPS results confirmed the formation of the CoFe2O4/Cd S nanocomposite.Based on the TEM analysis,the CoFe2O4/Cd S nanocomposite constituted nearly uniform,sphere-like nanoparticles of ～20 nm in size.The optical absorption spectrum of the CoFe2O4/Cd S nanocomposite displayed a band gap of 2.21 e V,which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants.Accordingly,the sonocatalytic activity of the CoFe2O4/Cd S nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue,rhodamine B,and methyl orange under ultrasonic irradiation.The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min.Furthermore,a comparison study revealed that the CoFe2O4/Cd S nanocomposite is a more efficient sonocatalyst than pure Cd S;thus,adopting the nanocomposite approach is an excellent means to improve the sonoactivity of Cd S.Moreover,the magnetic properties displayed by the CoFe2O4/Cd S nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.展开更多
A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐progr...A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐programmed reduction by H2,cyclic voltammetry,and temperature‐programmed desorption by O2.The results showed that Mo6+diffused into the Cu‐Fe‐O crystal lattice and then formed a new crystalline phase of CuMoO4.The Mo‐Cu‐Fe‐O catalyst had redox properties,and its surface contained active sites for oxygen adsorption.In addition,the catalytic activity of the Mo‐Cu‐Fe‐O composite was evaluated by the degradation of Cationic Red GTL,Crystal Violet,and Acid Red in catalytic wet air oxidation(CWAO)at ambient temperature and pressure.The Mo‐Cu‐Fe‐O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL.High removal efficiencies of91.5%and92.8%were achieved for Cationic Red GTL and Crystal Violet,respectively,in wastewater,and the efficiency remained high after seven cycles.However,almost no degradation of Acid Red occurred in the CWAO process.Furthermore,hydroxyl radicals were formed in the CWAO process,which induced the decomposition of the two cationic dyes in wastewater,and the toxicity of their effluents was decreased after degradation.The results indicate that the Mo‐Cu‐Fe‐O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.展开更多
Polyoxomolybdate [Mo36O110（NO）4（H2O）14].52H2O was synthesized by a simple one-pot procedure through reducing an acidified mixture of Na2MoO4.2H2O and NH2OH. HCl. In order to create a heterogeneous catalyst system,...Polyoxomolybdate [Mo36O110（NO）4（H2O）14].52H2O was synthesized by a simple one-pot procedure through reducing an acidified mixture of Na2MoO4.2H2O and NH2OH. HCl. In order to create a heterogeneous catalyst system, the polyoxomolybdate was pillared with MgAI-LDH-NO3 by direct ion exchange. These novel materials were carefully analyzed by various chemico-physical methods, The catalytic degradation of methylene blue （MB） and rhodamine B （RB） as common dyes in the presence of MgAl-LDH-1 nanoparticles with aqueous hydrogen peroxide, H2O2, as an oxidizing agent was studied in aqueous solution at room temperature. More importantly, the catalyst can be recovered and reused efficiently up to five consecutive cycles with negligible loss of catalytic activity.展开更多
Zinc oxide （ZnO） has been used as heterogeneous catalyst for the degradation of Acid Alizarin Black S dye （AAB） in aqueous solutions using UV light irradiation. Experiments were conducted at various operating para...Zinc oxide （ZnO） has been used as heterogeneous catalyst for the degradation of Acid Alizarin Black S dye （AAB） in aqueous solutions using UV light irradiation. Experiments were conducted at various operating parameters. The operating parameters were amount of catalyst （50 rag, 100 mg and 150 mg）, initial concentration of dye （30 mg/L, 50 mg/L and 70 mg/L）, the pH of solution （2, 4, 6, 8, l0 and 12） and the UV light intensity （6 watt and 12 watt）. The progress of the degradation reaction was monitored spectrophotometrically. It was found that the degradation process of AAB solution was accelerated with increased catalyst dosage and decreased initial concentration of AAB. It was also found that the removal efficiency of AAB significantly depend on pH value of solution. The results show that the degradation percent reaches the highest values with pH close to neutral. The data proved that removal percent of dye decreased when 6 watt lamp used instead of 12 watt lamp. The kinetic study confirmed that photocatalytic degradation of AAB dye follows a pseudo first order reaction rate.展开更多
Magnetic Fe_3O_4@PANI@Au nanocomposites are fabricated through electrostatic self-assembly and seed growth methods.The rate constant K_(app) is calculated to be 8.63×10^(-3) s^(-1) at room temperature for the red...Magnetic Fe_3O_4@PANI@Au nanocomposites are fabricated through electrostatic self-assembly and seed growth methods.The rate constant K_(app) is calculated to be 8.63×10^(-3) s^(-1) at room temperature for the reduction of 4-nitrophenol to 4-aminophenol with an excessive amount of NaBH_4 as a model system showing outstanding catalytic efficiency and stability.For recyclable performance,the catalyst exhibits slight loss in catalytic performance on the conversion of 4-nitrophenol after running for more than 10 cycles.Besides,the smaller and simpler the structure,the easier the molecular structure can be degraded,and the faster the cationic dyes can be degraded than the anionic dyes,which can reveal the selectivity.For practical application,Congo red as a pollutant of the lake water is degraded rapidly after Fe_3O_4@PANI@Au is added to the solution in a few minutes.It has been demonstrated that magnetic Fe_3O_4@PANI@Au nanoparticle composite is a promising catalyst for environment sewage.展开更多
A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both red...A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both reductant and surfactant for the first time. Time-dependent morphologic evolution was made in order to explore the formation mechanism of the as-prepared product. The copper selenides with different morphologies, phases and structural forms could be prepared by varying the synthesis parameters, such as precursor molar ratios, precursor combinations, and the molecular weight of PVP. The fernwort-like superstructures of CuSe show excellent Fenton-like catalytic activities in degrading malachite green （MG） and rhodamine B （RhB）. These catalysts play an important role in the degradation process of MG and RhB solution with the aid of H202 which can yield highly reactive hydroxyl radicals （HO.）. Besides, the as-prepared CuSe catalyst is stable and reusable, thus it could be applied to the treatment of the dye contaminated waste water.展开更多
基金supported by the National Natural Science Foundation of China(51672113,51602132)the Six Talent Peaks Project in Jiangsu Province(2015-XCL-026)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20171299)the Training Project of Jiangsu University for Young Cadre Teachers(5521220009)the Youth Research Project of Jiangsu Health and Family Planning Commission in 2016(Q201609)~~
文摘Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of highly active co-catalysts has proven to be a promising approach for improving photocatalytic activity. Thus far, the most developed co-catalysts for semiconductor-based photocatalysis are inorganic materials;the employment of a specific organic molecule as a co-catalyst for photocatalytic hydrogen evolution and pollutant photodegradation is rare and still remains a challenging task. Herein, we report on the use of an organic molecule, oxamide (OA), as a novel co-catalyst to enhance electron- hole separation, photocatalytic H2 evolution, and dye degradation over TiO2 nanosheets. OA-modified TiO2 samples were prepared by a wet chemical route and demonstrated improved light absorption in the visible-light region and more efficient charge transport. The photocatalytic performance of H2 evolution from water splitting and rhodamine B (RhB) degradation for an optimal OA-modified TiO2 photocatalyst reached 2.37 mmol g^–1 h^–1 and 1.43 × 10^-2 min^-1, respectively, which were 2.4 and 3.8 times higher than those of pristine TiO2, respectively. A possible mechanism is proposed, in which the specific π-conjugated structure of OA is suggested to play a key role in the enhancement of the charge transfer and catalytic capability of TiO2. This work may provide advanced insight into the development of a variety of metal-free organic molecules as functional co-catalysts for improved solar-to-fuel conversion and environmental remediation.
基金the Lorestan University and Iran Nanotechnology Initiative Council (INIC) for their financial support
文摘A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocomposite was characterised by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy,energy-dispersive X-ray spectroscopy（EDX）,UV-visible spectroscopy,transmission electron microscopy（TEM）,N2 gas sorption analysis,X-ray photoelectron spectroscopy（XPS）,and vibrating sample magnetometry.The FT-IR,XRD,EDX and XPS results confirmed the formation of the CoFe2O4/Cd S nanocomposite.Based on the TEM analysis,the CoFe2O4/Cd S nanocomposite constituted nearly uniform,sphere-like nanoparticles of ～20 nm in size.The optical absorption spectrum of the CoFe2O4/Cd S nanocomposite displayed a band gap of 2.21 e V,which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants.Accordingly,the sonocatalytic activity of the CoFe2O4/Cd S nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue,rhodamine B,and methyl orange under ultrasonic irradiation.The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min.Furthermore,a comparison study revealed that the CoFe2O4/Cd S nanocomposite is a more efficient sonocatalyst than pure Cd S;thus,adopting the nanocomposite approach is an excellent means to improve the sonoactivity of Cd S.Moreover,the magnetic properties displayed by the CoFe2O4/Cd S nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.
基金supported by the National Natural Science Foundation of China(51678511,51308484)the Natural Science Foundation of Hunan Province(13JJ4049)+3 种基金the Education Department Fund of Hunan Province(14C1094)the Open Fund of Key Laboratory of Mineralogy and Metallogeny in Chinese Academy of Sciences(KLMM20150104)the Major Talent Training Program of Xiangtan University(16PYZ09)the Specialized Research Fund for the Doctoral Program of Xiangtan University(12QDZ18)~~
文摘A novel‐structured Mo‐Cu‐Fe‐O composite was successfully prepared by co‐precipitation and impregnation method.The properties of the as‐prepared samples were determined using X‐ray diffraction,temperature‐programmed reduction by H2,cyclic voltammetry,and temperature‐programmed desorption by O2.The results showed that Mo6+diffused into the Cu‐Fe‐O crystal lattice and then formed a new crystalline phase of CuMoO4.The Mo‐Cu‐Fe‐O catalyst had redox properties,and its surface contained active sites for oxygen adsorption.In addition,the catalytic activity of the Mo‐Cu‐Fe‐O composite was evaluated by the degradation of Cationic Red GTL,Crystal Violet,and Acid Red in catalytic wet air oxidation(CWAO)at ambient temperature and pressure.The Mo‐Cu‐Fe‐O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL.High removal efficiencies of91.5%and92.8%were achieved for Cationic Red GTL and Crystal Violet,respectively,in wastewater,and the efficiency remained high after seven cycles.However,almost no degradation of Acid Red occurred in the CWAO process.Furthermore,hydroxyl radicals were formed in the CWAO process,which induced the decomposition of the two cationic dyes in wastewater,and the toxicity of their effluents was decreased after degradation.The results indicate that the Mo‐Cu‐Fe‐O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.
基金Supported by the Iranian National Science Foundation(INSF)and University of Maragheh
文摘Polyoxomolybdate [Mo36O110（NO）4（H2O）14].52H2O was synthesized by a simple one-pot procedure through reducing an acidified mixture of Na2MoO4.2H2O and NH2OH. HCl. In order to create a heterogeneous catalyst system, the polyoxomolybdate was pillared with MgAI-LDH-NO3 by direct ion exchange. These novel materials were carefully analyzed by various chemico-physical methods, The catalytic degradation of methylene blue （MB） and rhodamine B （RB） as common dyes in the presence of MgAl-LDH-1 nanoparticles with aqueous hydrogen peroxide, H2O2, as an oxidizing agent was studied in aqueous solution at room temperature. More importantly, the catalyst can be recovered and reused efficiently up to five consecutive cycles with negligible loss of catalytic activity.
文摘Zinc oxide （ZnO） has been used as heterogeneous catalyst for the degradation of Acid Alizarin Black S dye （AAB） in aqueous solutions using UV light irradiation. Experiments were conducted at various operating parameters. The operating parameters were amount of catalyst （50 rag, 100 mg and 150 mg）, initial concentration of dye （30 mg/L, 50 mg/L and 70 mg/L）, the pH of solution （2, 4, 6, 8, l0 and 12） and the UV light intensity （6 watt and 12 watt）. The progress of the degradation reaction was monitored spectrophotometrically. It was found that the degradation process of AAB solution was accelerated with increased catalyst dosage and decreased initial concentration of AAB. It was also found that the removal efficiency of AAB significantly depend on pH value of solution. The results show that the degradation percent reaches the highest values with pH close to neutral. The data proved that removal percent of dye decreased when 6 watt lamp used instead of 12 watt lamp. The kinetic study confirmed that photocatalytic degradation of AAB dye follows a pseudo first order reaction rate.
基金supported by the National Natural Science Foundation of China(Grant No.11272232)Science and Technology Supporting Major Project of Tianjin City(Grant No.16YFZCSY00850)
文摘Magnetic Fe_3O_4@PANI@Au nanocomposites are fabricated through electrostatic self-assembly and seed growth methods.The rate constant K_(app) is calculated to be 8.63×10^(-3) s^(-1) at room temperature for the reduction of 4-nitrophenol to 4-aminophenol with an excessive amount of NaBH_4 as a model system showing outstanding catalytic efficiency and stability.For recyclable performance,the catalyst exhibits slight loss in catalytic performance on the conversion of 4-nitrophenol after running for more than 10 cycles.Besides,the smaller and simpler the structure,the easier the molecular structure can be degraded,and the faster the cationic dyes can be degraded than the anionic dyes,which can reveal the selectivity.For practical application,Congo red as a pollutant of the lake water is degraded rapidly after Fe_3O_4@PANI@Au is added to the solution in a few minutes.It has been demonstrated that magnetic Fe_3O_4@PANI@Au nanoparticle composite is a promising catalyst for environment sewage.
基金supported by the National Natural Science Foundation of China (21375109)
文摘A simple green hydrothermal template-free method was developed to prepare single-crystalline superstructures of fern- wort-like copper selenide （CuSe） in large-scale by using polyvinylpyrrolidone （PVP） as both reductant and surfactant for the first time. Time-dependent morphologic evolution was made in order to explore the formation mechanism of the as-prepared product. The copper selenides with different morphologies, phases and structural forms could be prepared by varying the synthesis parameters, such as precursor molar ratios, precursor combinations, and the molecular weight of PVP. The fernwort-like superstructures of CuSe show excellent Fenton-like catalytic activities in degrading malachite green （MG） and rhodamine B （RhB）. These catalysts play an important role in the degradation process of MG and RhB solution with the aid of H202 which can yield highly reactive hydroxyl radicals （HO.）. Besides, the as-prepared CuSe catalyst is stable and reusable, thus it could be applied to the treatment of the dye contaminated waste water.
