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2019 Volume 35 Issue 3
2019, 35(3): 369-375
doi: 10.11862/CJIC.2019.056
Abstract:
The novel sulfur-doped ordered mesoporous carbon (S-OMC) was prepared via one-step hard-template method employing thymol blue as a single precursor. The S-OMC obtained at 900℃ showed appropriate graphitization degree and hierarchical pore structures with a high surface area of 1 230 m2·g-1 and a pore size distribution centered at 4.6 nm. These unique local structures and thio-phene S active sites for oxygen reduction reaction (ORR) contributed to the efficient catalytic performance of this ordered mesoporous carbon. It exhibited the ORR half wave potential of -0.21 V in 0.1 mol·L-1 KOH, and with superior stability and methanol tolerance in alkaline media. This one-step nanocasting route provides an industrially feasible synthesis for S doped ordered mesoporous carbon and shows efficient electroreduction activity for ORR compared to commercial Pt/C.
The novel sulfur-doped ordered mesoporous carbon (S-OMC) was prepared via one-step hard-template method employing thymol blue as a single precursor. The S-OMC obtained at 900℃ showed appropriate graphitization degree and hierarchical pore structures with a high surface area of 1 230 m2·g-1 and a pore size distribution centered at 4.6 nm. These unique local structures and thio-phene S active sites for oxygen reduction reaction (ORR) contributed to the efficient catalytic performance of this ordered mesoporous carbon. It exhibited the ORR half wave potential of -0.21 V in 0.1 mol·L-1 KOH, and with superior stability and methanol tolerance in alkaline media. This one-step nanocasting route provides an industrially feasible synthesis for S doped ordered mesoporous carbon and shows efficient electroreduction activity for ORR compared to commercial Pt/C.
2019, 35(3): 376-384
doi: 10.11862/CJIC.2019.035
Abstract:
Y3+ modified TiO2 photocatalysts were prepared by ball milling method. The structures and properties of the photocatalysts were characterized by UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activities were evaluated by the degradation of methylene blue (MB) aqueous solution under UV light, and the ball milling processes were optimized. Then Y3+/TiO2 photocatalysts prepared at the best conditions were coated on the plastic balls with different diameters. These balls were applied to treat shrimp wastewater under UV and visible light and CODCr (chemical oxygen demand) and 3D fluorescence spectroscopy were detected during the photocatalytic experiments. The results showed that when the molar ratio of Y3+ was 2%, milling time was 4 h, ball-to-powder weight ratio was 4:1 and milling rate was 500 r·min-1, the reaction rate constant of MB degradation can reach up to 0.111 3 min-1 which was 4.2 times as fast as pure TiO2. From the UV-Vis DRS, XPS, N2 absorption-desorption, XRD, SEM results, the band gap of 2%Y3+/TiO2 decreased to 3.05 eV. All Y3+/TiO2 samples showed a redshift of absorption compared to pure TiO2 and it led to visible light absorption response. The content of surface oxygen vacancy had a significant increase and the BET specific area increased to 104 m2 g-1. Pure TiO2 and 2%Y3+/TiO2 were used as photocatalysts to treat shrimp wastewater, CODCr removal rates were 14.7% and 18.8% under visible light, respectively. Moreover, CODCr removal rates were 26.9% and 37.5% under UV light, respectively. The photocatalytic efficiencies of three types of plastic ball with diameters of 1, 2 and 3 cm were investigated. The results showed that the performance of 2 cm balls was best and CODCr removal rate was 38.5%.
Y3+ modified TiO2 photocatalysts were prepared by ball milling method. The structures and properties of the photocatalysts were characterized by UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activities were evaluated by the degradation of methylene blue (MB) aqueous solution under UV light, and the ball milling processes were optimized. Then Y3+/TiO2 photocatalysts prepared at the best conditions were coated on the plastic balls with different diameters. These balls were applied to treat shrimp wastewater under UV and visible light and CODCr (chemical oxygen demand) and 3D fluorescence spectroscopy were detected during the photocatalytic experiments. The results showed that when the molar ratio of Y3+ was 2%, milling time was 4 h, ball-to-powder weight ratio was 4:1 and milling rate was 500 r·min-1, the reaction rate constant of MB degradation can reach up to 0.111 3 min-1 which was 4.2 times as fast as pure TiO2. From the UV-Vis DRS, XPS, N2 absorption-desorption, XRD, SEM results, the band gap of 2%Y3+/TiO2 decreased to 3.05 eV. All Y3+/TiO2 samples showed a redshift of absorption compared to pure TiO2 and it led to visible light absorption response. The content of surface oxygen vacancy had a significant increase and the BET specific area increased to 104 m2 g-1. Pure TiO2 and 2%Y3+/TiO2 were used as photocatalysts to treat shrimp wastewater, CODCr removal rates were 14.7% and 18.8% under visible light, respectively. Moreover, CODCr removal rates were 26.9% and 37.5% under UV light, respectively. The photocatalytic efficiencies of three types of plastic ball with diameters of 1, 2 and 3 cm were investigated. The results showed that the performance of 2 cm balls was best and CODCr removal rate was 38.5%.
2019, 35(3): 385-392
doi: 10.11862/CJIC.2019.054
Abstract:
Based on the functional complementarity between the reversible electrochromic property of the Dawson type polyanions P2W18O626- and the excellent luminescent property of Tb3+, the reversible electrochromic and luminescent switching properties of P2W18O626-@Tb3+ mixed solution were achieved under redox potential stimulation. The effects of applied reduction potential on electrochromic response time and the energy transfer efficiency of luminescent switch were investigated. And the energy transfer efficiency of the mixed solution P2W18O626-@Tb3+ were 85.97%, 87.53% and 93.42% when applied different reduction potential -0.38, -0.69 and -0.85 V, respectively. On this basis, the UV-Vis and fluorescence spectroscopy bi-functional detection for H2O2 were realized by combining electrochemical reduction with chemical oxidation methods. The detection limits for H2O2 were 1.76×10-2 and 3.04 μmol·L-1 by the UV-Vis and fluorescence spectroscopy, respectively.
Based on the functional complementarity between the reversible electrochromic property of the Dawson type polyanions P2W18O626- and the excellent luminescent property of Tb3+, the reversible electrochromic and luminescent switching properties of P2W18O626-@Tb3+ mixed solution were achieved under redox potential stimulation. The effects of applied reduction potential on electrochromic response time and the energy transfer efficiency of luminescent switch were investigated. And the energy transfer efficiency of the mixed solution P2W18O626-@Tb3+ were 85.97%, 87.53% and 93.42% when applied different reduction potential -0.38, -0.69 and -0.85 V, respectively. On this basis, the UV-Vis and fluorescence spectroscopy bi-functional detection for H2O2 were realized by combining electrochemical reduction with chemical oxidation methods. The detection limits for H2O2 were 1.76×10-2 and 3.04 μmol·L-1 by the UV-Vis and fluorescence spectroscopy, respectively.
2019, 35(3): 393-402
doi: 10.11862/CJIC.2019.068
Abstract:
Lanthanides-doped fluorescent silica nanoparticles(FSNPs) were synthesized via a two-step protocol:lanthanide ion was chelated with a conjugation of a chromophore, a ligand and a (3-aminopropyl)triethoxysilane (APTES) molecule. Then the complex was condensed in a water-in-oil microemulsion system together with tetraethyl orthosilicate (TEOS). The existence of coupling silane ensured the bonding in the formation of silica. The influence of water-to-surfactant molar ratio and the amount of prepared conjugation on controlling the particle size and the loading capacity of lanthanides were investigated. Meanwhile, an energy transfer process in lanthanides-doped FSNPs was illustrated by using different chromophores and lanthanides, so that made the excitation wavelength, emission wavelength and fluorescent intensity controllable. Thus, a framework was shaped for the design of silica nanoparticles with diverse fluorescent properties based on engineering the energy levels. In addition, the energy transfer process in rare earth doped FSNPs is further elaborated, and a new method for adjusting the fluorescence of FSNPs by energy level is proposed.
Lanthanides-doped fluorescent silica nanoparticles(FSNPs) were synthesized via a two-step protocol:lanthanide ion was chelated with a conjugation of a chromophore, a ligand and a (3-aminopropyl)triethoxysilane (APTES) molecule. Then the complex was condensed in a water-in-oil microemulsion system together with tetraethyl orthosilicate (TEOS). The existence of coupling silane ensured the bonding in the formation of silica. The influence of water-to-surfactant molar ratio and the amount of prepared conjugation on controlling the particle size and the loading capacity of lanthanides were investigated. Meanwhile, an energy transfer process in lanthanides-doped FSNPs was illustrated by using different chromophores and lanthanides, so that made the excitation wavelength, emission wavelength and fluorescent intensity controllable. Thus, a framework was shaped for the design of silica nanoparticles with diverse fluorescent properties based on engineering the energy levels. In addition, the energy transfer process in rare earth doped FSNPs is further elaborated, and a new method for adjusting the fluorescence of FSNPs by energy level is proposed.
2019, 35(3): 403-412
doi: 10.11862/CJIC.2019.066
Abstract:
The geometric structure, vibrational spectra and binding energies of[UO2(Uracil)j(H2O)k]2+ (Uijk, i represents six kinds of uracil tautomers and j+k=5) have been studied by B3LYP method with 6-311++G(d, p) and RLC ECP basis sets. The solvent effect of water was simulated by polarized continuum model. The results show that as the number of the uracil increases, the U-Ouracil bond and the U=O bond in coordination ions are elongated and the stretching vibrational frequencies of the U=O bond gradually decrease in the aqueous solution. Meanwhile, the total binding energies of the coordination ions obviously increase, and the calculation also shows a linear relationship between the binding energies and the number of uracil ligand. Besides, the affinity of uracil ligand for the uranyl ion far exceeds that of H2O ligand. The U-Ouracil bond lengths calculated in the gaseous phase are slightly shorter than those obtained in the aqueous phase, however, the lengths of the U-OH2 bond show opposite behavior. In the Ui14 system, the bond length of U-Ouracil is negatively correlated with the bond length of U-OH2, while is positively correlated with the vibrational frequency of U=O bond. The maximum binding energy of the coordination ion is evidently not formed by the lowest energy conformer of uracil. The topological analysis of electron density indicates that the coordination bond shows ionic character. Atomic charge analysis reveals that the charge transfer is from uracil to uranyl during the coordination process, and the amount of the uracil charge is inversely related with coordination number. The Ur6 tautomer possesses the most charge among six kinds of uracil tautomers because of forming bidentate complexation with uranyl.
The geometric structure, vibrational spectra and binding energies of[UO2(Uracil)j(H2O)k]2+ (Uijk, i represents six kinds of uracil tautomers and j+k=5) have been studied by B3LYP method with 6-311++G(d, p) and RLC ECP basis sets. The solvent effect of water was simulated by polarized continuum model. The results show that as the number of the uracil increases, the U-Ouracil bond and the U=O bond in coordination ions are elongated and the stretching vibrational frequencies of the U=O bond gradually decrease in the aqueous solution. Meanwhile, the total binding energies of the coordination ions obviously increase, and the calculation also shows a linear relationship between the binding energies and the number of uracil ligand. Besides, the affinity of uracil ligand for the uranyl ion far exceeds that of H2O ligand. The U-Ouracil bond lengths calculated in the gaseous phase are slightly shorter than those obtained in the aqueous phase, however, the lengths of the U-OH2 bond show opposite behavior. In the Ui14 system, the bond length of U-Ouracil is negatively correlated with the bond length of U-OH2, while is positively correlated with the vibrational frequency of U=O bond. The maximum binding energy of the coordination ion is evidently not formed by the lowest energy conformer of uracil. The topological analysis of electron density indicates that the coordination bond shows ionic character. Atomic charge analysis reveals that the charge transfer is from uracil to uranyl during the coordination process, and the amount of the uracil charge is inversely related with coordination number. The Ur6 tautomer possesses the most charge among six kinds of uracil tautomers because of forming bidentate complexation with uranyl.
2019, 35(3): 413-421
doi: 10.11862/CJIC.2019.051
Abstract:
The δ-MnO2 catalysts doped with different metal ions Mn+ (Mn+=Co2+, Cu2+, Fe3+, Al3+, Ce4+) were prepared by hydrothermal method, which was referred to as MMn for catalytic oxidation of chlorobenzene. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 absorption-desorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR). The results showed that the catalytic efficiency of chlorobenzene under the same reaction conditions was:AlMn > FeMn > CeMn > CuMn > δ-MnO2 > CoMn. The higher specific surface area, the lower reducible temperature and more surface active oxygen Osur of Al-doped δ-MnO2 catalyst are important factors for higher catalytic activity.
The δ-MnO2 catalysts doped with different metal ions Mn+ (Mn+=Co2+, Cu2+, Fe3+, Al3+, Ce4+) were prepared by hydrothermal method, which was referred to as MMn for catalytic oxidation of chlorobenzene. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 absorption-desorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR). The results showed that the catalytic efficiency of chlorobenzene under the same reaction conditions was:AlMn > FeMn > CeMn > CuMn > δ-MnO2 > CoMn. The higher specific surface area, the lower reducible temperature and more surface active oxygen Osur of Al-doped δ-MnO2 catalyst are important factors for higher catalytic activity.
2019, 35(3): 422-432
doi: 10.11862/CJIC.2019.053
Abstract:
The nitrogen-doped nanocomposite based on TiO2 nanoparticles and HTi2NbO7 nanosheets was success-fully synthesized by the following procedures:Layered CsTi2NbO7 was firstly prepared by high temperature solid-state method, and then treated with HNO3 solution to obtain layered HTi2NbO7 by proton-exchange reaction. The resulted layered HTi2NbO7 was well dispersed in tetrabutylammonium hydroxide (TBAOH) solution in order to prepare HTi2NbO7 nanosheets by exfoliation reaction and then freeze-dried treatment. Finally, to prepare nitrogen-doped TiO2/HTi2NbO7 nanosheets (denoted as N-TTN) nanocomposites, the mixtures of the freeze-dried HTi2NbO7 nanosheets and titanium(Ⅳ) isopropoxide were calcinated in the presence of urea as N source. The as-prepared samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoelectrochemical properties measurements, UV-Vis spectroscopy as well as N2 adsorption-desorption measurements. It was found that anatase TiO2 nanoparticles were well-distributed on the surface of HTi2NbO7 nanosheets, resulting in the formation of heterojunction structure between two components. The photocatalytic activities of samples were evaluated by the photodegradation of rhodamine B (RhB) under visible light irradiation. It indicated that the resultant N-TTN nanocomposite showed a highest photocatalytic activity toward the degradation of RhB, owing to the synergistic effects of nitrogen doping, the formation of heterojunction, increased specific surface area and rich mesoporous structure.
The nitrogen-doped nanocomposite based on TiO2 nanoparticles and HTi2NbO7 nanosheets was success-fully synthesized by the following procedures:Layered CsTi2NbO7 was firstly prepared by high temperature solid-state method, and then treated with HNO3 solution to obtain layered HTi2NbO7 by proton-exchange reaction. The resulted layered HTi2NbO7 was well dispersed in tetrabutylammonium hydroxide (TBAOH) solution in order to prepare HTi2NbO7 nanosheets by exfoliation reaction and then freeze-dried treatment. Finally, to prepare nitrogen-doped TiO2/HTi2NbO7 nanosheets (denoted as N-TTN) nanocomposites, the mixtures of the freeze-dried HTi2NbO7 nanosheets and titanium(Ⅳ) isopropoxide were calcinated in the presence of urea as N source. The as-prepared samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoelectrochemical properties measurements, UV-Vis spectroscopy as well as N2 adsorption-desorption measurements. It was found that anatase TiO2 nanoparticles were well-distributed on the surface of HTi2NbO7 nanosheets, resulting in the formation of heterojunction structure between two components. The photocatalytic activities of samples were evaluated by the photodegradation of rhodamine B (RhB) under visible light irradiation. It indicated that the resultant N-TTN nanocomposite showed a highest photocatalytic activity toward the degradation of RhB, owing to the synergistic effects of nitrogen doping, the formation of heterojunction, increased specific surface area and rich mesoporous structure.
2019, 35(3): 433-441
doi: 10.11862/CJIC.2019.050
Abstract:
Cerium oxide/Bismuth molybdate catalysts were synthesized by hydrothermal method. The relationships between cerium oxide and the composition, structure, photocatalytic activity of Bismuth molybdate were further investigated under the different acid-base reaction system solutions. The samples were characterized by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy. It was found that the addition of CeO2 seriously affected the morphology, composition, structure and photocatalytic properties of bismuth molybdate in different acid-base synthesis systems. The reaction product was more beneficial to the formation of Bi2MoO6 in the acidic system and made for the formation of Bi3.64Mo0.36O6.55/Bi2MoO6 in alkaline condition without CeO2. When CeO2 was added to reaction-solution system, the composition and structure of the substances were almost unchanged in the acidic system; the photocatalytic activity was greatly enhanced. The morphology, composition, structure and photocatalytic properties of the materials have changed greatly under alkaline conditions. The reaction product was more beneficial to the formation of Bi3.64Mo0.36O6.55. Therefore, under alkaline conditions, the addition of CeO2 promoted the conversion of Bi2MoO6 to Bi3.64Mo0.36O6.55.
Cerium oxide/Bismuth molybdate catalysts were synthesized by hydrothermal method. The relationships between cerium oxide and the composition, structure, photocatalytic activity of Bismuth molybdate were further investigated under the different acid-base reaction system solutions. The samples were characterized by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy. It was found that the addition of CeO2 seriously affected the morphology, composition, structure and photocatalytic properties of bismuth molybdate in different acid-base synthesis systems. The reaction product was more beneficial to the formation of Bi2MoO6 in the acidic system and made for the formation of Bi3.64Mo0.36O6.55/Bi2MoO6 in alkaline condition without CeO2. When CeO2 was added to reaction-solution system, the composition and structure of the substances were almost unchanged in the acidic system; the photocatalytic activity was greatly enhanced. The morphology, composition, structure and photocatalytic properties of the materials have changed greatly under alkaline conditions. The reaction product was more beneficial to the formation of Bi3.64Mo0.36O6.55. Therefore, under alkaline conditions, the addition of CeO2 promoted the conversion of Bi2MoO6 to Bi3.64Mo0.36O6.55.
2019, 35(3): 442-448
doi: 10.11862/CJIC.2019.060
Abstract:
Based on the synergetic effects among hydrogen bond donors, halide anions and suitable amines for the CO2 cycloaddition reaction, the multi-functionalized graphene oxide (containing silanol group, quaternary ammonium salt and tertiary amine) were synthesized by a "in-situ approach". Hexamethylenetetramine that is non-toxic, cheap and rich in tertiary amine was used as precursor for quaternary ammonium salt. Then, further quaternization was conducted by adding halohydrocarbon for the formation of multi-cationic quaternary ammonium salt functionalized graphene oxide (F-GO) heterogeneous catalysts. As characterized by X-ray photoelectron spectroscopy and elemental analysis, the loading of quaternary ammonium salt and tertiary amine was up to 2.23 and 2.49 mmol·g-1, respectively. The "multi-cationic approach" is proved to be beneficial to improve the amount of ionic liquids and catalytic activity. The F-GO was used as metal-free heterogeneous catalyst for the synthesis of cyclic carbonates through the cycloaddition of CO2 towards propylene epoxide under mild conditions without solvent and co-catalyst. The yield of propylene carbonate was up to 99.2% (100℃, 2 MPa, 4 h). The synergetic effects was investigated by comparing the catalytic activity of F-GO functionalized with different groups. A plausible mechanism was proposed for the CO2 cycloaddition reaction over F-GO. In addition, F-GO is a water-tolerant and stable catalyst for the cycloaddition reaction, and there was no significant loss of catalytic activity after six runs.
Based on the synergetic effects among hydrogen bond donors, halide anions and suitable amines for the CO2 cycloaddition reaction, the multi-functionalized graphene oxide (containing silanol group, quaternary ammonium salt and tertiary amine) were synthesized by a "in-situ approach". Hexamethylenetetramine that is non-toxic, cheap and rich in tertiary amine was used as precursor for quaternary ammonium salt. Then, further quaternization was conducted by adding halohydrocarbon for the formation of multi-cationic quaternary ammonium salt functionalized graphene oxide (F-GO) heterogeneous catalysts. As characterized by X-ray photoelectron spectroscopy and elemental analysis, the loading of quaternary ammonium salt and tertiary amine was up to 2.23 and 2.49 mmol·g-1, respectively. The "multi-cationic approach" is proved to be beneficial to improve the amount of ionic liquids and catalytic activity. The F-GO was used as metal-free heterogeneous catalyst for the synthesis of cyclic carbonates through the cycloaddition of CO2 towards propylene epoxide under mild conditions without solvent and co-catalyst. The yield of propylene carbonate was up to 99.2% (100℃, 2 MPa, 4 h). The synergetic effects was investigated by comparing the catalytic activity of F-GO functionalized with different groups. A plausible mechanism was proposed for the CO2 cycloaddition reaction over F-GO. In addition, F-GO is a water-tolerant and stable catalyst for the cycloaddition reaction, and there was no significant loss of catalytic activity after six runs.
2019, 35(3): 449-458
doi: 10.11862/CJIC.2019.061
Abstract:
The nano boehmite (γ-AlO(OH)) was synthesized by template-free hydrothermal method with aluminum nitrate as the aluminum source and urea as the precipitant. The final products aluminum oxide (γ-Al2O3 and θ-Al2O3) were obtained by calcined at different temperatures. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), transmission electron microscopy (TEM), Fourier transfer infrared (FTIR), nitrogen adsorption-desorption method and UV-visible Spectrophotometer (UV-Vis). The adsorption properties of the product for methyl orange (MO) was studied, and the effect of adsorption time, pH value of the solution, methyl orange concentration and recycling on the adsorption performance of the products systematically were investigated. In addition, the adsorption theory studies on the adsorption process was conducted. The results showed that the products obtained by this method are more dispersible, uniform and complete in morphology compared to the products prepared by other methods. The products were highly dispersed nano-bundled structure. The maximum adsorption of γ-AlO(OH) on methyl orange reached 1 492.5 mg·g-1. The adsorption mechanism of the products includes chemical adsorption mechanism, electrostatic adsorption mechanism and so on. The adsorption of MO on the three products accord with the Langmuir monolayer adsorption model, and the adsorption process are consistent with the pseudo-second-order kinetic.
The nano boehmite (γ-AlO(OH)) was synthesized by template-free hydrothermal method with aluminum nitrate as the aluminum source and urea as the precipitant. The final products aluminum oxide (γ-Al2O3 and θ-Al2O3) were obtained by calcined at different temperatures. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), transmission electron microscopy (TEM), Fourier transfer infrared (FTIR), nitrogen adsorption-desorption method and UV-visible Spectrophotometer (UV-Vis). The adsorption properties of the product for methyl orange (MO) was studied, and the effect of adsorption time, pH value of the solution, methyl orange concentration and recycling on the adsorption performance of the products systematically were investigated. In addition, the adsorption theory studies on the adsorption process was conducted. The results showed that the products obtained by this method are more dispersible, uniform and complete in morphology compared to the products prepared by other methods. The products were highly dispersed nano-bundled structure. The maximum adsorption of γ-AlO(OH) on methyl orange reached 1 492.5 mg·g-1. The adsorption mechanism of the products includes chemical adsorption mechanism, electrostatic adsorption mechanism and so on. The adsorption of MO on the three products accord with the Langmuir monolayer adsorption model, and the adsorption process are consistent with the pseudo-second-order kinetic.
2019, 35(3): 459-466
doi: 10.11862/CJIC.2019.052
Abstract:
Carbon nanotubes (CNTs)were treated with the mixed acid (VH2SO4/VHNO3=3:1). Cu2O/CNTs spherical composites were synthesized by one-step solvothermal method, using ethylene glycol as reductant and acid-treated CNTs as the carrier. Cu2O/CNTs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy spectrum analysis (EDS), N2 adsorption-desorption, ultraviolet-visible diffuse reflectance spectrometer (DRS)and organic total carbon (TOC). The influence of CNTs on the crystal structure, morphology, surface area, pore size and optical characteristics of Cu2O/CNTs composites was investigated. The relationship between CNTs and photocatalytic performance of Cu2O/CNTs in combination with photocatalytic mechanism was analyzed. The results showed that the photocatalytic activity of Cu2O/CNTs was the best when the content of CNTs was 0.2 g, and the degradation rate of methyl orange reached 92.1% after degradation for 60 min.
Carbon nanotubes (CNTs)were treated with the mixed acid (VH2SO4/VHNO3=3:1). Cu2O/CNTs spherical composites were synthesized by one-step solvothermal method, using ethylene glycol as reductant and acid-treated CNTs as the carrier. Cu2O/CNTs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy spectrum analysis (EDS), N2 adsorption-desorption, ultraviolet-visible diffuse reflectance spectrometer (DRS)and organic total carbon (TOC). The influence of CNTs on the crystal structure, morphology, surface area, pore size and optical characteristics of Cu2O/CNTs composites was investigated. The relationship between CNTs and photocatalytic performance of Cu2O/CNTs in combination with photocatalytic mechanism was analyzed. The results showed that the photocatalytic activity of Cu2O/CNTs was the best when the content of CNTs was 0.2 g, and the degradation rate of methyl orange reached 92.1% after degradation for 60 min.
2019, 35(3): 467-476
doi: 10.11862/CJIC.2019.039
Abstract:
Scanning electron microscope(SEM), laser confocal microscope(LSM), flow cytometry methods were used to comparatively study the toxicity difference of nano and micron calcium oxalate monohydrate(COM)on the African green monkey kidney epithelial(Vero)cells. The results revealed that both nano and micron COM could decrease cell viability, increase LDH release amount, up-regulate HA expression, decrease lysosomal integrity, decrease mitochondrial membrane potential, increased cell death rate and arrest cell cycle, which indicated that both nano and micron COM crystals could damage Vero cells and presented concentration dependent. But nano COM exhibited higher cytotoxicity and more adhesion amount than micron COM. This study may provide insights into the damage to renal epithelial cells induced by urinary crystals and the formation mechanism of kidney stones.
Scanning electron microscope(SEM), laser confocal microscope(LSM), flow cytometry methods were used to comparatively study the toxicity difference of nano and micron calcium oxalate monohydrate(COM)on the African green monkey kidney epithelial(Vero)cells. The results revealed that both nano and micron COM could decrease cell viability, increase LDH release amount, up-regulate HA expression, decrease lysosomal integrity, decrease mitochondrial membrane potential, increased cell death rate and arrest cell cycle, which indicated that both nano and micron COM crystals could damage Vero cells and presented concentration dependent. But nano COM exhibited higher cytotoxicity and more adhesion amount than micron COM. This study may provide insights into the damage to renal epithelial cells induced by urinary crystals and the formation mechanism of kidney stones.
2019, 35(3): 485-492
doi: 10.11862/CJIC.2019.062
Abstract:
The LiMn0.6Fe0.4PO4/C materials with high energy density have been prepared successfully by improved sol-gel method, using Mn(NO3)2, Fe(NO3)3·9H2O, NH4H2PO4 and LiOH·H2O as main raw materials. The primary nanoparticles were constructed into secondary particles by the framework of metal and ligand complexes, and the obtained cathode materials showed excellent electrochemical performance and rather high energy density. The energy density of batteries could be increased by 30%. The crystal structure, morphology and electrochemical performance of the materials were systematically characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), electrochemical impedance spectroscopy (EIS), tap density, particle size and electrochemical tests. The results showed that LiMn0.6Fe0.4PO4/C not only has high tap density and median voltage, but also has excellent electrochemical performances. The tap density was 1.3 g·cm-3. The median voltage of discharge was 3.85 V at 1C, the capacity still achieved 142.3 mAh·g-1 after 100 cycles.
The LiMn0.6Fe0.4PO4/C materials with high energy density have been prepared successfully by improved sol-gel method, using Mn(NO3)2, Fe(NO3)3·9H2O, NH4H2PO4 and LiOH·H2O as main raw materials. The primary nanoparticles were constructed into secondary particles by the framework of metal and ligand complexes, and the obtained cathode materials showed excellent electrochemical performance and rather high energy density. The energy density of batteries could be increased by 30%. The crystal structure, morphology and electrochemical performance of the materials were systematically characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), electrochemical impedance spectroscopy (EIS), tap density, particle size and electrochemical tests. The results showed that LiMn0.6Fe0.4PO4/C not only has high tap density and median voltage, but also has excellent electrochemical performances. The tap density was 1.3 g·cm-3. The median voltage of discharge was 3.85 V at 1C, the capacity still achieved 142.3 mAh·g-1 after 100 cycles.
2019, 35(3): 493-504
doi: 10.11862/CJIC.2019.067
Abstract:
The effects of microwave-assisted hydrothermal synthesis on the morphology and photocatalytic properties of a flower globular-like heterostructure composite were investigated. By the microwave-assisted hydrothermal two step process, ZnS/ZnO/ZnWO4 composite was prepared. The crystal structure, composition, morphology, surface physicochemical properties and optical absorption properties were characterized by using X-ray diffraction (XRD), ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and N2 adsorption-desorption tests. The results showed that the composite exhibited a uniform flower globular-like shape. The flower structure consists of cubic ZnS nanoparticles, hexagonal ZnO and monoclinic ZnWO4 nanorods. The grain size, specific surface area and pore volume of ZnO/ZnWO4 composites were larger than those of ZnWO4 composites due to microwave polarization. Moreover, microwave irradiation compounded ZnS and further increased the grain size of composite ZnS/ZnO/ZnWO4. However, the specific surface area and pore volume of composite ZnS/ZnO/ZnWO4 decreased due to the compactness of the inner sphere, but the composite still maintained a flower-like structure. The multimode photocatalytic degradation of malachite green enhanced by flower globular ZnS/ZnO/ZnWO4 was studied. The experimental results of hydrogen production from photolysis water showed that ZnS/ZnO/ZnWO4 composites had excellent hydrogen production ability (376.9 μmol·h-1·g-1), which was 246.5 times higher than that of commercial P25. The enhanced hydrogen production performance of the composites is related to the excellent flower globular shape, ternary heterostructure and multi-pathway photoelectron migration in photocatalytic reaction.
The effects of microwave-assisted hydrothermal synthesis on the morphology and photocatalytic properties of a flower globular-like heterostructure composite were investigated. By the microwave-assisted hydrothermal two step process, ZnS/ZnO/ZnWO4 composite was prepared. The crystal structure, composition, morphology, surface physicochemical properties and optical absorption properties were characterized by using X-ray diffraction (XRD), ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and N2 adsorption-desorption tests. The results showed that the composite exhibited a uniform flower globular-like shape. The flower structure consists of cubic ZnS nanoparticles, hexagonal ZnO and monoclinic ZnWO4 nanorods. The grain size, specific surface area and pore volume of ZnO/ZnWO4 composites were larger than those of ZnWO4 composites due to microwave polarization. Moreover, microwave irradiation compounded ZnS and further increased the grain size of composite ZnS/ZnO/ZnWO4. However, the specific surface area and pore volume of composite ZnS/ZnO/ZnWO4 decreased due to the compactness of the inner sphere, but the composite still maintained a flower-like structure. The multimode photocatalytic degradation of malachite green enhanced by flower globular ZnS/ZnO/ZnWO4 was studied. The experimental results of hydrogen production from photolysis water showed that ZnS/ZnO/ZnWO4 composites had excellent hydrogen production ability (376.9 μmol·h-1·g-1), which was 246.5 times higher than that of commercial P25. The enhanced hydrogen production performance of the composites is related to the excellent flower globular shape, ternary heterostructure and multi-pathway photoelectron migration in photocatalytic reaction.
2019, 35(3): 505-514
doi: 10.11862/CJIC.2019.048
Abstract:
Two nickel(Ⅱ) and two zinc(Ⅱ) coordination polymers, namely {[Ni(μ-5-Clnic)(μ3-5-Clnic)(μ-H2O)0.5]·1.5H2O}n (1), [Ni(5-Clnic)(μ-5-Clnic)(H2biim)]n (2), [Zn(5-Clnic)(μ-5-Clnic)(H2biim)]n (3) and {[Zn(5-Clnic)(μ-5-Clnic)(phen)]·2H2O}n (4), have been constructed hydrothermally using 5-ClnicH (5-ClnicH=5-chloronicotinic acid), phen (phen=1, 10-phenanthroline), H2biim (H2biim=2, 2'-biimidazole), and nickel or zinc chlorides. Single-crystal X-ray diffraction analyses revealed that four polymers crystallize in the monoclinic, orthorhombic (2, 3) or triclinic systems, space groups I2/a, Pbcn (2, 3) or P1. Polymer 1 possesses a 3D metal-organic framework based on dinuclear units. Polymers 2~4 show 1D chains, which are further extended into a 2D supramolecular network or 3D supramolecular framework through N-H…O hydrogen bonds or Cl…Cl interactions. Magnetic and luminescent properties of all compounds have been studied.
Two nickel(Ⅱ) and two zinc(Ⅱ) coordination polymers, namely {[Ni(μ-5-Clnic)(μ3-5-Clnic)(μ-H2O)0.5]·1.5H2O}n (1), [Ni(5-Clnic)(μ-5-Clnic)(H2biim)]n (2), [Zn(5-Clnic)(μ-5-Clnic)(H2biim)]n (3) and {[Zn(5-Clnic)(μ-5-Clnic)(phen)]·2H2O}n (4), have been constructed hydrothermally using 5-ClnicH (5-ClnicH=5-chloronicotinic acid), phen (phen=1, 10-phenanthroline), H2biim (H2biim=2, 2'-biimidazole), and nickel or zinc chlorides. Single-crystal X-ray diffraction analyses revealed that four polymers crystallize in the monoclinic, orthorhombic (2, 3) or triclinic systems, space groups I2/a, Pbcn (2, 3) or P1. Polymer 1 possesses a 3D metal-organic framework based on dinuclear units. Polymers 2~4 show 1D chains, which are further extended into a 2D supramolecular network or 3D supramolecular framework through N-H…O hydrogen bonds or Cl…Cl interactions. Magnetic and luminescent properties of all compounds have been studied.
2019, 35(3): 515-523
doi: 10.11862/CJIC.2019.057
Abstract:
A semi-rigid bi-functional multi-dentate ligand 5-(4-((1H-1, 2, 4-triazol-1-yl)methyl)phenyl)-1H-tetrazole (HL) has been employed to prepare two polymorphic zinc(Ⅱ) coordination polymers, namely[Zn(μ2-L)2]n (1) and[Zn(μ2-L)2]n (2) under hydrothermal conditions. Complexes 1 and 2 present temperature induced polymorphic zinc(Ⅱ)-L 1D (1) and 2D (2) coordination frameworks. In 1, 1D left-and right-handed helical chains are inter-linked to form a 1D chain zinc(Ⅱ)-L coordination polymer. In 2, these 1D left-and right-handed helical chains are also interlinked via central zinc(Ⅱ) ions forming the two-dimensional(2D) coordination framework. The photoluminescent properties of free HL and 1~2 have been investigated, indicating strong emissions. Additionally, photoluminescent experiment also demonstrates that complex 2 exhibits highly sensitive luminescence sensing for picric acid in the aqueous solutions with high quenching efficiency (KSV=3.65×103 L·mol-1) and low detection limit (3.004 μmol·L-1, S/N=3), which make it a promising candidate for sensing picric acid.
A semi-rigid bi-functional multi-dentate ligand 5-(4-((1H-1, 2, 4-triazol-1-yl)methyl)phenyl)-1H-tetrazole (HL) has been employed to prepare two polymorphic zinc(Ⅱ) coordination polymers, namely[Zn(μ2-L)2]n (1) and[Zn(μ2-L)2]n (2) under hydrothermal conditions. Complexes 1 and 2 present temperature induced polymorphic zinc(Ⅱ)-L 1D (1) and 2D (2) coordination frameworks. In 1, 1D left-and right-handed helical chains are inter-linked to form a 1D chain zinc(Ⅱ)-L coordination polymer. In 2, these 1D left-and right-handed helical chains are also interlinked via central zinc(Ⅱ) ions forming the two-dimensional(2D) coordination framework. The photoluminescent properties of free HL and 1~2 have been investigated, indicating strong emissions. Additionally, photoluminescent experiment also demonstrates that complex 2 exhibits highly sensitive luminescence sensing for picric acid in the aqueous solutions with high quenching efficiency (KSV=3.65×103 L·mol-1) and low detection limit (3.004 μmol·L-1, S/N=3), which make it a promising candidate for sensing picric acid.
2019, 35(3): 524-536
doi: 10.11862/CJIC.2019.042
Abstract:
Two new mononuclear Cu(Ⅱ) and trinuclear Ni(Ⅱ) Salamo-type complexes, namely[CuL] (1) and[Ni3(L)2(μ-OAc)2(CH3OH)2]·CH3OH (2), derived from a new containing coumarin-skeleton ligand H2L were prepared and characterized by the means of elemental analyses, FT-IR, UV-Visible absorption spectra, single-crystal X-ray diffractions, fluorescence spectra, thermal (TG-DTA) properties and Hirshfeld surface analyses. The X-ray crystallography demonstrated that the Cu(Ⅱ) ion in the[N2O2] coordination sphere is four-coordinated forming a distorted square planar geometry in complex 1. Meanwhile, all Ni(Ⅱ) ions are six-coordinated and have the distorted octahedral coordination geometries in complex 2. The methanol molecule as a ligand participates in the coordination of complex 2. The strong supramolecular structures are formed via hydrogen bonding and C-H…π interactions in complexes 1 and 2. In addition, the thermal stabilities and Hirshfeld surface analyses of complexes 1 and 2 were analyzed in detail, and the fluorescent properties of complexes 1 and 2 were also investigated.
Two new mononuclear Cu(Ⅱ) and trinuclear Ni(Ⅱ) Salamo-type complexes, namely[CuL] (1) and[Ni3(L)2(μ-OAc)2(CH3OH)2]·CH3OH (2), derived from a new containing coumarin-skeleton ligand H2L were prepared and characterized by the means of elemental analyses, FT-IR, UV-Visible absorption spectra, single-crystal X-ray diffractions, fluorescence spectra, thermal (TG-DTA) properties and Hirshfeld surface analyses. The X-ray crystallography demonstrated that the Cu(Ⅱ) ion in the[N2O2] coordination sphere is four-coordinated forming a distorted square planar geometry in complex 1. Meanwhile, all Ni(Ⅱ) ions are six-coordinated and have the distorted octahedral coordination geometries in complex 2. The methanol molecule as a ligand participates in the coordination of complex 2. The strong supramolecular structures are formed via hydrogen bonding and C-H…π interactions in complexes 1 and 2. In addition, the thermal stabilities and Hirshfeld surface analyses of complexes 1 and 2 were analyzed in detail, and the fluorescent properties of complexes 1 and 2 were also investigated.
2019, 35(3): 546-552
doi: 10.11862/CJIC.2019.064
Abstract:
Two Zn(Ⅱ) coordination complexes, formulated as {[Zn1.5(dbim)1.5(btc)]·6H2O}n (1) and {[Zn(dbim)0.5(btec)0.5(H2O)]·H2O}n (2) (dbim=1-(4-((2, 6-dimethyl-2H-benzo[d]imidazol-3(3H)-yl)methyl)benzyl)-2, 7-dihydro-2, 5-dimethyl-1H-benzo[d]imidazole, H3btc=trimesic acid, H4btec=1, 2, 4, 5-benzene tetracarboxylic), have been obtained by hydrothermal reactions. Complex 1 is a trinodal (3, 4, 4)-connected topology net with the point symbol of (52·6·7·82)(52·6) (52·62·82), while complex 2 possesses a (3, 4)-connected 3D topology with the point symbol of (83)(85·10) topology. Additionally, complexes 1 and 2 exhibit different photoluminescence behaviors in solid state compared to ligand dbim.
Two Zn(Ⅱ) coordination complexes, formulated as {[Zn1.5(dbim)1.5(btc)]·6H2O}n (1) and {[Zn(dbim)0.5(btec)0.5(H2O)]·H2O}n (2) (dbim=1-(4-((2, 6-dimethyl-2H-benzo[d]imidazol-3(3H)-yl)methyl)benzyl)-2, 7-dihydro-2, 5-dimethyl-1H-benzo[d]imidazole, H3btc=trimesic acid, H4btec=1, 2, 4, 5-benzene tetracarboxylic), have been obtained by hydrothermal reactions. Complex 1 is a trinodal (3, 4, 4)-connected topology net with the point symbol of (52·6·7·82)(52·6) (52·62·82), while complex 2 possesses a (3, 4)-connected 3D topology with the point symbol of (83)(85·10) topology. Additionally, complexes 1 and 2 exhibit different photoluminescence behaviors in solid state compared to ligand dbim.
2019, 35(3): 553-562
doi: 10.11862/CJIC.2019.055
Abstract:
Highly active bimetallic Au@Pt core-shell catalysts were prepared by using direct-adsorption method, in which uniformly dispersed Au@Pt nanoparticles synthesized using two-step liquid-phase hydrogen reduction method were directly loaded on support. The performance of the catalysts for catalytic oxidation of toluene was evaluated. The catalysts were characterized by transmission electron microscopy (TEM) in conjunction with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption and temperature-programmed reduction (H2-TPR). As a result, the bimetallic Au@Pt core-shell catalysts exhibited higher catalytic activity compared with monometallic Au or Pt catalyst, and the Au1@Pt2/Al2O3 core-shell catalyst showed outstanding catalytic activity, selectivity and stability among the bimetallic catalysts. The temperature for conversion of 98% toluene (T98) was 195℃ under the condition of toluene volume fraction at 1×10-3 and the gas hourly space velocity of 18 L·g-1·h-1.The XPS results illustrated that the enhancement of catalytic activity is attributed to the presence of Au underneath Pt shell where electron exchange from Au to Pt has promoted the formation of active oxygen species on Pt, which facilitates the oxidation of toluene. In addition, the active components of the catalyst mainly existed in the form of Au0 and Pt0, and the strong interaction between the Au@Pt nanoparticles and the support was observed.
Highly active bimetallic Au@Pt core-shell catalysts were prepared by using direct-adsorption method, in which uniformly dispersed Au@Pt nanoparticles synthesized using two-step liquid-phase hydrogen reduction method were directly loaded on support. The performance of the catalysts for catalytic oxidation of toluene was evaluated. The catalysts were characterized by transmission electron microscopy (TEM) in conjunction with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption and temperature-programmed reduction (H2-TPR). As a result, the bimetallic Au@Pt core-shell catalysts exhibited higher catalytic activity compared with monometallic Au or Pt catalyst, and the Au1@Pt2/Al2O3 core-shell catalyst showed outstanding catalytic activity, selectivity and stability among the bimetallic catalysts. The temperature for conversion of 98% toluene (T98) was 195℃ under the condition of toluene volume fraction at 1×10-3 and the gas hourly space velocity of 18 L·g-1·h-1.The XPS results illustrated that the enhancement of catalytic activity is attributed to the presence of Au underneath Pt shell where electron exchange from Au to Pt has promoted the formation of active oxygen species on Pt, which facilitates the oxidation of toluene. In addition, the active components of the catalyst mainly existed in the form of Au0 and Pt0, and the strong interaction between the Au@Pt nanoparticles and the support was observed.
2019, 35(3): 563-568
doi: 10.11862/CJIC.2019.037
Abstract:
Two complexes, namely[Ni(L)(HL)](SO4)0.5·3CH3OH (1) and[Cu2(L)2SO4]·1.5CH3OH (2) (HL=3-methyl-2-acetylpyrazine benzoylhydrazone) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. X-ray diffraction analysis results showed that in complex 1, the center Ni(Ⅱ) ion with a distorted octahedron geometry is surrounded by two acylhydrazones with[ONN] donor set. However, complex 2 contains one discrete dimeric Cu(Ⅱ) molecule in the unit cell, in which two Cu(Ⅱ) ions were doubly bridged by two O atoms from two independent acylhydrazone ligands. Each of the Cu(Ⅱ) ions is also coordinated by two N atoms from one L- ligand and one O atom from the η2-SO42- anion, thus giving a distorted square pyramid coordination geometry. Moreover, the fluorescence spectra indicated that the interaction of the complexes to DNA is stronger than that of the ligand HL.CCDC 1876785: 1; 1876789: 2.
Two complexes, namely[Ni(L)(HL)](SO4)0.5·3CH3OH (1) and[Cu2(L)2SO4]·1.5CH3OH (2) (HL=3-methyl-2-acetylpyrazine benzoylhydrazone) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. X-ray diffraction analysis results showed that in complex 1, the center Ni(Ⅱ) ion with a distorted octahedron geometry is surrounded by two acylhydrazones with[ONN] donor set. However, complex 2 contains one discrete dimeric Cu(Ⅱ) molecule in the unit cell, in which two Cu(Ⅱ) ions were doubly bridged by two O atoms from two independent acylhydrazone ligands. Each of the Cu(Ⅱ) ions is also coordinated by two N atoms from one L- ligand and one O atom from the η2-SO42- anion, thus giving a distorted square pyramid coordination geometry. Moreover, the fluorescence spectra indicated that the interaction of the complexes to DNA is stronger than that of the ligand HL.CCDC 1876785: 1; 1876789: 2.
