Ce O2@Si O2 core-shell nanoparticles were prepared by microemulsion method, and metalloporphyrins were immobilized on the Ce O2@Si O2 core-shell nanoparticles surface via amide bond. The supported metalloporphyrin cat...Ce O2@Si O2 core-shell nanoparticles were prepared by microemulsion method, and metalloporphyrins were immobilized on the Ce O2@Si O2 core-shell nanoparticles surface via amide bond. The supported metalloporphyrin catalysts were characterized by N2 adsorption-desorption isotherm(BET), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), ultraviolet and visible spectroscopy(UV-Vis), and Fourier transform infrared spectroscopy(FT-IR). The results show that the morphology of Ce O2@Si O2 nanoparticles is core-shell microspheres with about 30 nm in diameter, and metalloporphyrins are immobilized on the Ce O2@Si O2 core-shell nanoparticles via amide bond. Especially, the core-shell structure contains multi Ce O2 core and thin Si O2 shell, which may benefit the synergistic effect between the Ce O2 core and the porphyrin anchored on the very thin Si O2 shell. As a result, this supported metalloporphyrin catalysts present comparably high catalytic activity and stability for oxidation of ethylbenzene with molecular oxygen, namely, ethylbenzene conversion remains around 12% with identical selectivity of about 80% for acetophenone even after six-times reuse of the catalyst.展开更多
Atomically dispersed catalysts have shown promising prospects in catalysis studies.Among all of the developed methods for synthesizing atomically dispersed catalysts,the photochemical approach has recently aroused muc...Atomically dispersed catalysts have shown promising prospects in catalysis studies.Among all of the developed methods for synthesizing atomically dispersed catalysts,the photochemical approach has recently aroused much attention owing to its simple procedure and mild preparation conditions involved.In the present study,we demonstrate the application of the photochemical method to synthesize atomically dispersed Pd catalysts on(001)‐exposed anatase nanocrystals and commercial TiO2(P25).The as‐prepared catalysts exhibit both high activity and stability in the hydrogenation of styrene and catalytic oxidation of CO.展开更多
Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS (tetraethyl orthosilicate)....Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS (tetraethyl orthosilicate).Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM (scanning electron microscopy).The conversion of toluene and para-xylene selectivity were influenced remarkably by the n(SiO2)/n(Al2O3) ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.展开更多
Molybdenum (VI) complex, namely molybdenum dioxobis(2,4-pentanedione) [MoO2(acac)2] used as epoxidation catalyst species, was synthesized and characterized by elemental analysis and infrared spectrum. Polystyrene-supp...Molybdenum (VI) complex, namely molybdenum dioxobis(2,4-pentanedione) [MoO2(acac)2] used as epoxidation catalyst species, was synthesized and characterized by elemental analysis and infrared spectrum. Polystyrene-supported molybdenum dioxobis(2,4-pentanedione) [MoO2(acac)2] for synthesis of epoxycyclohexane was prepared by phase transfer catalysis method. Effects of various factors in synthesis of epoxycyclohexane by reaction of cyclohexene and t-BuOOH in the atmosphere of nitrogen catalyzed by polystyrene-supported MoO2(acac)2 were also investigated. Under the following conditions, n(cyclohexene):n(t-BuOOH)=3.5:l (based on 0.1 mol of t-BuOOH), volume of solvent -10ml, reaction temperature -80℃, reaction time -60min, and mass of molybdenum in the catalyst -2.30×0^(-3)g, the yield of epoxycyclohexane on the basis of t-BuOOH is over 99.5%, and the purity of epoxycyclohexane is about 99.9% by gas chromatogram(GC) analysis.展开更多
A novel vehicle for the delivery of aspirin (ASA) was prepared from porous nano-hydroxyapafite/poly(styrene-divinylbenzene) [nano-HAP/P(St-DVB)] composite microspheres by grafting nano-HAP [Ca10(PO4)6(OH)2] ...A novel vehicle for the delivery of aspirin (ASA) was prepared from porous nano-hydroxyapafite/poly(styrene-divinylbenzene) [nano-HAP/P(St-DVB)] composite microspheres by grafting nano-HAP [Ca10(PO4)6(OH)2] onto porous P(St-DVB) micro- spheres. Four types of porous composite microspheres were prepared, each with different nano-HAP contents. The ASA-loaded composite microspheres prepared with 10% and 15% nano-HAP (mass ratio) exhibited excellent buoyancy with relatively short instantaneous floating time (within l0 min) and a long sustained floating time (12 h) in simulated gastric juice. They also offered good sustained release of ASA (up to 8 h). Furthermore, these composite microspheres displayed good buff- ering capacity that prevented the buildup of acidity caused by hydrolysis of ASA, keeping the pH of gastric juice within the normal range (pH 0.9 to 1.5). The results showed that porous nano-HAP/P(St-DVB) composite microspheres prepared with 10% and 15% nano-HAP could be used as a novel drug carrier for ASA, providing a sustained release dose without leading to stomach irritation, a side effect that is often associated with ASA medication.展开更多
Silver nanowires (AgNWs) surrounded by insulating poly(vinylpyrrolidone) have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heatt...Silver nanowires (AgNWs) surrounded by insulating poly(vinylpyrrolidone) have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heattreatment at about 200 ℃ which forms connecting junctions between AgNWs. Such a heating process is, however, one of the drawbacks of the fabrication of AgNW electrodes on heat-sensitive substrates. Here it has been demonstrated that the electrical conductivity of AgNW electrodes can be improved by mechanical pressing at 25 MPa for 5 s at room temperature. This simple process results in a low sheet resistance of 8.6 Ω/square and a transparency of 80.0%, equivalent to the properties of the AgNW electrodes heated at 200 ℃. This technique makes it possible to fabricate AgNW transparent electrodes on heat-sensitive substrates. The AgNW electrodes on poly(ethylene terephthalate) films exhibited high stability of their electrical conductivities against the repeated bending test. In addition, the surface roughness of the pressed AgNW electrodes is one-third of that of the heat-treated electrode because the AgNW junctions are mechanically compressed. As a result, an organic solar cell fabricated on the pressed AgNW electrodes exhibited a power conversion as much as those fabricated on indium tin oxide electrodes. These findings enable continuous roll-to-roll processing at room temperature, resulting in relatively simple, inexpensive, and scalable processing that is suitable for forthcoming technologies such as organic solar cells, flexible displays, and touch screens.展开更多
Various polysulfonamide (PSA) statistical copolymers were synthesized by polycondensation of three aromatic diamines and terephthaloyl chloride. The inherent viscosities of the resulting PSA copolymers range from 1....Various polysulfonamide (PSA) statistical copolymers were synthesized by polycondensation of three aromatic diamines and terephthaloyl chloride. The inherent viscosities of the resulting PSA copolymers range from 1.54 to 1.66 dL/g. The precipitated PSA copolymers with feed content of p-phenylene diamine (PPD) being less than 50% (mole fraction) can be redissolved in N-methyl-2-pryrrolidone (NMP) or N, N-dimethylacetamide (DMAc) with lithium chloride of WLiC1 : 0.02. All of the PSA copolymers exhibit enhanced tensile strength in comparison with PSA and still maintain excellent thermal stability in either air or nitrogen atmosphere展开更多
CdS nanocrystals have been successfully grown on porous silicon(PS) by sol-gel method. The plan-view field emission scanning electron microscopy(FESEM) shows that the pore size of PS is smaller than 5 μm in diameter ...CdS nanocrystals have been successfully grown on porous silicon(PS) by sol-gel method. The plan-view field emission scanning electron microscopy(FESEM) shows that the pore size of PS is smaller than 5 μm in diameter and the agglomerates of Cd S are broadly distributed on the surface of PS substrate. With the increase of annealing time, the Cd S nanoparticles grow in both length and diameter along the preferred orientation. The cross-sectional FESEM images of Zn O/PS show that Cd S nanocrystals are uniformly penetrated into all PS layers and adhere to them very well. photoluminescence(PL) spectra demonstrate that the intensity of PL peak located at about 425 nm has almost no change after the annealing time increases. The range of emission wavelength of Cd S/PS is from 425 nm to 455 nm and the PL intensity is decreasing with the annealing temperature increasing from 100 °C to 200 °C.展开更多
基金Projects(J21103045,J1210040,J1103312) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities of China
文摘Ce O2@Si O2 core-shell nanoparticles were prepared by microemulsion method, and metalloporphyrins were immobilized on the Ce O2@Si O2 core-shell nanoparticles surface via amide bond. The supported metalloporphyrin catalysts were characterized by N2 adsorption-desorption isotherm(BET), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), ultraviolet and visible spectroscopy(UV-Vis), and Fourier transform infrared spectroscopy(FT-IR). The results show that the morphology of Ce O2@Si O2 nanoparticles is core-shell microspheres with about 30 nm in diameter, and metalloporphyrins are immobilized on the Ce O2@Si O2 core-shell nanoparticles via amide bond. Especially, the core-shell structure contains multi Ce O2 core and thin Si O2 shell, which may benefit the synergistic effect between the Ce O2 core and the porphyrin anchored on the very thin Si O2 shell. As a result, this supported metalloporphyrin catalysts present comparably high catalytic activity and stability for oxidation of ethylbenzene with molecular oxygen, namely, ethylbenzene conversion remains around 12% with identical selectivity of about 80% for acetophenone even after six-times reuse of the catalyst.
基金supported by the Ministry of Science and Technology of nano major research projects(2015CB932303)the National Natural Science Foundation of China(21420102001,21131005,21333008,21390390)~~
文摘Atomically dispersed catalysts have shown promising prospects in catalysis studies.Among all of the developed methods for synthesizing atomically dispersed catalysts,the photochemical approach has recently aroused much attention owing to its simple procedure and mild preparation conditions involved.In the present study,we demonstrate the application of the photochemical method to synthesize atomically dispersed Pd catalysts on(001)‐exposed anatase nanocrystals and commercial TiO2(P25).The as‐prepared catalysts exhibit both high activity and stability in the hydrogenation of styrene and catalytic oxidation of CO.
基金Supported by the Key Natural Science Foundation for Universities of Jiangsu Province(06KJA53012) the National Natural Science Foundation of China(20776069 20976084)
文摘Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS (tetraethyl orthosilicate).Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM (scanning electron microscopy).The conversion of toluene and para-xylene selectivity were influenced remarkably by the n(SiO2)/n(Al2O3) ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.
基金Supported by the Outstanding Personality Innovation Funds of Henan Province(No.0121001900).
文摘Molybdenum (VI) complex, namely molybdenum dioxobis(2,4-pentanedione) [MoO2(acac)2] used as epoxidation catalyst species, was synthesized and characterized by elemental analysis and infrared spectrum. Polystyrene-supported molybdenum dioxobis(2,4-pentanedione) [MoO2(acac)2] for synthesis of epoxycyclohexane was prepared by phase transfer catalysis method. Effects of various factors in synthesis of epoxycyclohexane by reaction of cyclohexene and t-BuOOH in the atmosphere of nitrogen catalyzed by polystyrene-supported MoO2(acac)2 were also investigated. Under the following conditions, n(cyclohexene):n(t-BuOOH)=3.5:l (based on 0.1 mol of t-BuOOH), volume of solvent -10ml, reaction temperature -80℃, reaction time -60min, and mass of molybdenum in the catalyst -2.30×0^(-3)g, the yield of epoxycyclohexane on the basis of t-BuOOH is over 99.5%, and the purity of epoxycyclohexane is about 99.9% by gas chromatogram(GC) analysis.
基金financially supported by the Young Scientists Fund of the Natural Science Foundation of Heilongjiang Province (QC2011C099)Scientific Fund of Heilongjiang Province Department of Health (2009-259)+3 种基金Grant from Educational Office of Heilongjiang Province (11551178 and1154HZ11)Fund of Daqing GaoXin Qu (DQGX09YF016)the National Natural Science Foundation of China (30871007)the Natural Science Foundation of Heilongjiang Province (ZD2008-08 and LC2009C12)
文摘A novel vehicle for the delivery of aspirin (ASA) was prepared from porous nano-hydroxyapafite/poly(styrene-divinylbenzene) [nano-HAP/P(St-DVB)] composite microspheres by grafting nano-HAP [Ca10(PO4)6(OH)2] onto porous P(St-DVB) micro- spheres. Four types of porous composite microspheres were prepared, each with different nano-HAP contents. The ASA-loaded composite microspheres prepared with 10% and 15% nano-HAP (mass ratio) exhibited excellent buoyancy with relatively short instantaneous floating time (within l0 min) and a long sustained floating time (12 h) in simulated gastric juice. They also offered good sustained release of ASA (up to 8 h). Furthermore, these composite microspheres displayed good buff- ering capacity that prevented the buildup of acidity caused by hydrolysis of ASA, keeping the pH of gastric juice within the normal range (pH 0.9 to 1.5). The results showed that porous nano-HAP/P(St-DVB) composite microspheres prepared with 10% and 15% nano-HAP could be used as a novel drug carrier for ASA, providing a sustained release dose without leading to stomach irritation, a side effect that is often associated with ASA medication.
文摘Silver nanowires (AgNWs) surrounded by insulating poly(vinylpyrrolidone) have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heattreatment at about 200 ℃ which forms connecting junctions between AgNWs. Such a heating process is, however, one of the drawbacks of the fabrication of AgNW electrodes on heat-sensitive substrates. Here it has been demonstrated that the electrical conductivity of AgNW electrodes can be improved by mechanical pressing at 25 MPa for 5 s at room temperature. This simple process results in a low sheet resistance of 8.6 Ω/square and a transparency of 80.0%, equivalent to the properties of the AgNW electrodes heated at 200 ℃. This technique makes it possible to fabricate AgNW transparent electrodes on heat-sensitive substrates. The AgNW electrodes on poly(ethylene terephthalate) films exhibited high stability of their electrical conductivities against the repeated bending test. In addition, the surface roughness of the pressed AgNW electrodes is one-third of that of the heat-treated electrode because the AgNW junctions are mechanically compressed. As a result, an organic solar cell fabricated on the pressed AgNW electrodes exhibited a power conversion as much as those fabricated on indium tin oxide electrodes. These findings enable continuous roll-to-roll processing at room temperature, resulting in relatively simple, inexpensive, and scalable processing that is suitable for forthcoming technologies such as organic solar cells, flexible displays, and touch screens.
基金the National Natural Science Foundation of China (No. 50973059)the Scientific Research Foundation of 2009 Graduate School of Shanghai University
文摘Various polysulfonamide (PSA) statistical copolymers were synthesized by polycondensation of three aromatic diamines and terephthaloyl chloride. The inherent viscosities of the resulting PSA copolymers range from 1.54 to 1.66 dL/g. The precipitated PSA copolymers with feed content of p-phenylene diamine (PPD) being less than 50% (mole fraction) can be redissolved in N-methyl-2-pryrrolidone (NMP) or N, N-dimethylacetamide (DMAc) with lithium chloride of WLiC1 : 0.02. All of the PSA copolymers exhibit enhanced tensile strength in comparison with PSA and still maintain excellent thermal stability in either air or nitrogen atmosphere
基金supported by the Xinjiang Science and Technology Project(No.2015211C275)
文摘CdS nanocrystals have been successfully grown on porous silicon(PS) by sol-gel method. The plan-view field emission scanning electron microscopy(FESEM) shows that the pore size of PS is smaller than 5 μm in diameter and the agglomerates of Cd S are broadly distributed on the surface of PS substrate. With the increase of annealing time, the Cd S nanoparticles grow in both length and diameter along the preferred orientation. The cross-sectional FESEM images of Zn O/PS show that Cd S nanocrystals are uniformly penetrated into all PS layers and adhere to them very well. photoluminescence(PL) spectra demonstrate that the intensity of PL peak located at about 425 nm has almost no change after the annealing time increases. The range of emission wavelength of Cd S/PS is from 425 nm to 455 nm and the PL intensity is decreasing with the annealing temperature increasing from 100 °C to 200 °C.