Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculation...Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculations. For the minimization of H[Al]ZSM 5, significant geometric rearrangements have been investigated in the local environments of Brnsted acidic sites, which resulted from the isomorphous substitution of Al for Si atoms in MFI framework.展开更多
LaPO_4 and hydroxyapatite(Ca_(10)(PO_4)_6(OH)_2)are typical metal phosphates recently found to be useful for making supported metal or metal oxide catalysts,but CePO_4(also belonging to the metal phosphate family)has ...LaPO_4 and hydroxyapatite(Ca_(10)(PO_4)_6(OH)_2)are typical metal phosphates recently found to be useful for making supported metal or metal oxide catalysts,but CePO_4(also belonging to the metal phosphate family)has been rarely used to make supported catalysts.It would be interesting to develop CePO_4-supported catalysts and explore their catalytic applications.Herein,hexagonal CePO_4 nanorods(denoted as CePO_4-H),hexagonal CePO_4 nanowires(CePO_4-HNW),monoclinic CePO_4 nanoparticles(CePO_4-M),and monoclinic CePO_4 nanowires(CePO_4-MNW)prepared by different methods were used to support gold via deposition-precipitation with urea(DPU).The gold contents of these catalysts were all around 1 wt%.The catalytic activities of these Au/CePO_4 catalysts in CO oxidation were found to follow the sequence of Au/CePO_4-MNW>Au/CePO_4-HNW> Au/CePO_4-M>Au/CePO_4-H.These catalysts were characterized by inductively coupled plasma-optical emission spectroscopy(ICP-OES),N_2 adsorption–desorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),oxygen temperature-programmed desorption(O_2-TPD),and CO_2 temperature-programmed desorption(CO_2-TPD)to find possible correlations between the physicochemical properties and catalytic activities of these catalysts.展开更多
A novel chain complex was synthesized and its crystal structure has been deter- mined by X-ray diffraction technique. It was found that the local coordination geometry around Cu(Ⅱ) is a distorted tetrahedron and C14H...A novel chain complex was synthesized and its crystal structure has been deter- mined by X-ray diffraction technique. It was found that the local coordination geometry around Cu(Ⅱ) is a distorted tetrahedron and C14H9CuNO3CH3OH is bridged by the carboxylate oxygen atom to form an infinite one-dimensional linear chain. The hydrogen bond exists between O(1) and solvate molecule O(4). The crystal belongs to monoclinic, space group P21 with a = 9.6650(19), b = 7.1280(14), c = 9.925(2) ? b = 98.39(3)? V = 676.4(2) 3, Z = 2, F(000) = 342 and m(MoK? = 1.629 mm-1 .展开更多
A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi ...A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.展开更多
A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is pre-sented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followe...A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is pre-sented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated tempera-tures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air cal-cining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150―200℃, and then by washing with hydro-chloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the tem-perature of the hydrothermal treatment, the calcination at 400―500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180―200℃) produced monoclinic TiO2 nanosheets with a uniform mor-phology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles.展开更多
文摘Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculations. For the minimization of H[Al]ZSM 5, significant geometric rearrangements have been investigated in the local environments of Brnsted acidic sites, which resulted from the isomorphous substitution of Al for Si atoms in MFI framework.
基金Supported by the National Natural Science Foundation of China(21177028 and21477022)
文摘LaPO_4 and hydroxyapatite(Ca_(10)(PO_4)_6(OH)_2)are typical metal phosphates recently found to be useful for making supported metal or metal oxide catalysts,but CePO_4(also belonging to the metal phosphate family)has been rarely used to make supported catalysts.It would be interesting to develop CePO_4-supported catalysts and explore their catalytic applications.Herein,hexagonal CePO_4 nanorods(denoted as CePO_4-H),hexagonal CePO_4 nanowires(CePO_4-HNW),monoclinic CePO_4 nanoparticles(CePO_4-M),and monoclinic CePO_4 nanowires(CePO_4-MNW)prepared by different methods were used to support gold via deposition-precipitation with urea(DPU).The gold contents of these catalysts were all around 1 wt%.The catalytic activities of these Au/CePO_4 catalysts in CO oxidation were found to follow the sequence of Au/CePO_4-MNW>Au/CePO_4-HNW> Au/CePO_4-M>Au/CePO_4-H.These catalysts were characterized by inductively coupled plasma-optical emission spectroscopy(ICP-OES),N_2 adsorption–desorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),oxygen temperature-programmed desorption(O_2-TPD),and CO_2 temperature-programmed desorption(CO_2-TPD)to find possible correlations between the physicochemical properties and catalytic activities of these catalysts.
文摘A novel chain complex was synthesized and its crystal structure has been deter- mined by X-ray diffraction technique. It was found that the local coordination geometry around Cu(Ⅱ) is a distorted tetrahedron and C14H9CuNO3CH3OH is bridged by the carboxylate oxygen atom to form an infinite one-dimensional linear chain. The hydrogen bond exists between O(1) and solvate molecule O(4). The crystal belongs to monoclinic, space group P21 with a = 9.6650(19), b = 7.1280(14), c = 9.925(2) ? b = 98.39(3)? V = 676.4(2) 3, Z = 2, F(000) = 342 and m(MoK? = 1.629 mm-1 .
基金Supported by the National Natural Science Foundation of China(21676023,21376025)
文摘A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.
基金This work was supported by the National Natu-ral Science Foundation of China(Grant Nos．201253l0 and 20443008)the National Basic Research Program of China (Grant No．2003CB6 1 5804)．
文摘A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is pre-sented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated tempera-tures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air cal-cining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150―200℃, and then by washing with hydro-chloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the tem-perature of the hydrothermal treatment, the calcination at 400―500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180―200℃) produced monoclinic TiO2 nanosheets with a uniform mor-phology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles.
