共查询到6条相似文献,搜索用时 15 毫秒
1.
B,N-TiO2 photocatalysts were synthesized by boron doping firstly and subsequently nitrogen doping in NH3 at variable temperatures. The effects of the nitrogen doping temperature on the structure and photocatalytic activity of the B,N-codoped TiO2 were investigated. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectrum (DRS), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated with photocatalytic degradation of methyl orange dye (MO) under visible light and UV-visible light irradiation. The results suggested that the boron and nitrogen can be incorporated into the TiO2 lattice either interstitially or substitutionally or both, while the Ti-O-B-N structure plays a vital role in photocatalytic activity in visible light region. The optimal nitrogen doping temperature is 550 °C. Higher temperature may form many oxygen vacancies and Ti3+ species, resulting in the decrease of photocatalytic activity in visible light. 相似文献
2.
Magorzata Maciejewska Joanna Osypiuk Barbara Gawdzik 《Journal of polymer science. Part A, Polymer chemistry》2005,43(14):3049-3058
The preparation of porous ethylene glycol dimethacrylate/divinylbenzene polymeric microspheres is presented. These materials were investigated as column packings for high‐performance liquid chromatography. Their porous structures in both the dry and wet states were also studied. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3049–3058, 2005 相似文献
3.
Marta Grochowicz Barbara Gawdzik Andrzej Bartnicki 《Journal of polymer science. Part A, Polymer chemistry》2009,47(12):3190-3201
Synthesis and properties of the new aromatic tetrafunctional methacrylate monomer 1,3‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of pore‐forming diluents, decan‐1‐ol and chlorobenzene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3190–3201, 2009 相似文献
4.
Teresa Basinska Stanislaw Slomkowski Slawomir Kazmierski Andrzej Dworak Mohamed M. Chehimi 《Journal of polymer science. Part A, Polymer chemistry》2004,42(3):615-623
The composition and properties of the surface layers of poly(styrene/α-t-butoxy-ω-polyglycidol) [poly(styrene/VB-polyGL)] microspheres synthesized by the radical copolymerization of styrene and α-t-butoxy-ω-vinylbenzyl-polyglycidol (VB-polyGL) macromonomers [number-average molecular weight (Mn) = 950 or 2700] were investigated with X-ray photoelectron spectroscopy, 13C NMR, and the adsorption of human serum albumin and γ-globulins. The number-average diameter of the synthesized microspheres was 220 nm. Their surface layers were rich in polyglycidol, with polyglycidol-to-polystyrene unit ratios of 0.443 (VB-polyGL with Mn = 950) and 0.427 (VB-polyGL with Mn = 2700). In suspensions of poly(styrene/VB-polyGL) particles in D2O, the polymer chains in the polyglycidol-rich surface layers were highly mobile, allowing the registration of polyglycidol 13C NMR spectra with standard procedures for polymer solutions. In these spectra, the signals of the relatively immobile polystyrene segments were absent. The spin–lattice relaxation times (T1) measured for polyglycidol in the microsphere surface layers and for VB-polyGL macromonomers in solution were very close, indicating similar degrees of motion in bound (in particle surface layers) and free (in solution) polyglycidol macromolecules. Studies of protein adsorption revealed that hydrophilic polyglycidol layers were protein-repellent. It was found that longer polyglycidol chains in particle surface layers were more mobile (higher T1 values) and provided better protection against protein adsorption. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 615–623, 2004 相似文献
5.
Beata Podkocielna Barbara Gawdzik Andrzej Bartnicki 《Journal of polymer science. Part A, Polymer chemistry》2006,44(24):7014-7026
A new aromatic, tetrafunctional methacrylate monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone, and its application to the synthesis of porous microspheres are presented. This new monomer was copolymerized with divinylbenzene in the presence of pore‐forming diluents. The properties of the obtained highly crosslinked microspheres were investigated as column packing for high‐performance liquid chromatography. Their porous structures in both dry and wet states were studied and compared with those of poly(divinylbenzene) and the less crosslinked copolymer of 2,3‐epoxypropyl methacrylate and divinylbenzene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7014–7026, 2006 相似文献
6.
以九水合硝酸铁为原料, 利用改进的聚合诱导胶体聚集(PICA)的方法制备出三维网络状多级孔结构氧化铁(HPH). 此结构的制备关键是在合成过程中尿素和甲醛聚合生成脲醛树脂(UF). 脲醛树脂一方面在铁的羟基氧化物生长过程中与之杂化形成杂化产物Fe-UF, 另一方面则进一步聚合, 形成脲醛树脂微球(UFM). 脲醛树脂微球作为模板诱导杂化产物Fe-UF在其表面的聚集. 微球与微球之间则由于表面存在的脲醛树脂间的聚合会相互交联形成网络状结构. 经过煅烧处理后, 脲醛树脂及脲醛树脂微球的分解导致不同尺寸孔结构的生成. 光催化研究结果表明, 产物对罗丹明B的降解效率是商用纳米氧化铁的4倍. 相似文献