A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- no...A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.展开更多
A series of Mo-doped ZnO photocatalysts with different Mo-dopant concentrations have been prepared by a grind- ing-calcination method. The structure of these photocatalysts was characterized by a variety of methods, i...A series of Mo-doped ZnO photocatalysts with different Mo-dopant concentrations have been prepared by a grind- ing-calcination method. The structure of these photocatalysts was characterized by a variety of methods, including N2 physical adsorption, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） spectroscopy, photoluminescence （PL） emission spectroscopy, and UV-vis diffuse reflectance spectroscopy （DRS）. It was found that Mo6＋ could enter into the crystal lattice of ZnO due to the radius of MO6＋ （0.065 nm） being smaller than that of Zn2＋ （0.083 nm）. XRD results indicated that Mo6＋ suppressed the growth of ZnO crystals. The FT-IR spectroscopy results showed that the ZnO with 2 wt.% Mo-doping has a higher level of surface hydroxyl groups than pure ZnO. PL spectroscopy indicated that ZnO with 2 wt.% Mo-doping also exhibited the largest reduction in the intensity of the emission peak at 390 nm caused by the recombi- nation of photogenerated hole-electron pairs. The activities of the Mo-doped ZnO photocatalysts were investigated in the pho- tocatalytic degradation of acid orange II under UV light （2 = 365 nm） irradiation. It was found that ZnO with 2 wt.% Mo-doping showed much higher photocatalytic activity and stability than pure ZnO. The high photocatalytic performance of the Mo-doped ZnO can be attributed to a great improvement in the surface properties of ZnO, higher crystallinity and lower recombination rate of photogenerated hole-electron （e-/h＋） pairs. Moreover, the undoped Mo species may exist in the form of MoO3 and form MoO3/ZnO heterojunctions which further favors the separation of e/h＋ pairs.展开更多
基金Supported by Chinese Program for New Century Excellent Talents in University "NCET",Ministry of Education of P.R. China(No.2008DFA51170)
文摘A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.
基金supported by the National Natural Science Foundation ofChina (21067004)the Natural Science Foundation of Jiangxi Province,China (2010GZH0048)Jiangxi Province Educatien Department of Science and Technology Project (GJJ 12344)
文摘A series of Mo-doped ZnO photocatalysts with different Mo-dopant concentrations have been prepared by a grind- ing-calcination method. The structure of these photocatalysts was characterized by a variety of methods, including N2 physical adsorption, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） spectroscopy, photoluminescence （PL） emission spectroscopy, and UV-vis diffuse reflectance spectroscopy （DRS）. It was found that Mo6＋ could enter into the crystal lattice of ZnO due to the radius of MO6＋ （0.065 nm） being smaller than that of Zn2＋ （0.083 nm）. XRD results indicated that Mo6＋ suppressed the growth of ZnO crystals. The FT-IR spectroscopy results showed that the ZnO with 2 wt.% Mo-doping has a higher level of surface hydroxyl groups than pure ZnO. PL spectroscopy indicated that ZnO with 2 wt.% Mo-doping also exhibited the largest reduction in the intensity of the emission peak at 390 nm caused by the recombi- nation of photogenerated hole-electron pairs. The activities of the Mo-doped ZnO photocatalysts were investigated in the pho- tocatalytic degradation of acid orange II under UV light （2 = 365 nm） irradiation. It was found that ZnO with 2 wt.% Mo-doping showed much higher photocatalytic activity and stability than pure ZnO. The high photocatalytic performance of the Mo-doped ZnO can be attributed to a great improvement in the surface properties of ZnO, higher crystallinity and lower recombination rate of photogenerated hole-electron （e-/h＋） pairs. Moreover, the undoped Mo species may exist in the form of MoO3 and form MoO3/ZnO heterojunctions which further favors the separation of e/h＋ pairs.
