TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations ...TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.展开更多
本文利用纳米TiO2粉体,以聚乙烯吡咯烷（PVP）为分散剂和结构引导剂,以正硅酸乙酯（TEOS）为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧...本文利用纳米TiO2粉体,以聚乙烯吡咯烷（PVP）为分散剂和结构引导剂,以正硅酸乙酯（TEOS）为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧基硅烷（HDTMS）低表面能修饰后,得到抗紫外和超疏水复合功能棉织物。探究制备纳米TiO2-SiO2复合粒子的最佳工艺,并对复合粒子和处理后棉织物进行表征。结果表明,当PVP用量为0.025%,硅钛比例为2∶1,氨水用量为5 m L时,纳米SiO2包覆TiO2效果较好。处理棉织物的抗紫外指数（UPF）达115.42,紫外线UVA（320420 nm）透过率为3.35%,接触角为156.54°,滚动角为8°,具有优异的抗紫外、超疏水性能。此外,处理棉织物经过24 h紫外线照射后,接触角仍为152.73°,滚动角仍可达到9°,实现了耐紫外线稳定性。展开更多
In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds ...In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.展开更多
文摘TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.
文摘本文利用纳米TiO2粉体,以聚乙烯吡咯烷（PVP）为分散剂和结构引导剂,以正硅酸乙酯（TEOS）为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧基硅烷（HDTMS）低表面能修饰后,得到抗紫外和超疏水复合功能棉织物。探究制备纳米TiO2-SiO2复合粒子的最佳工艺,并对复合粒子和处理后棉织物进行表征。结果表明,当PVP用量为0.025%,硅钛比例为2∶1,氨水用量为5 m L时,纳米SiO2包覆TiO2效果较好。处理棉织物的抗紫外指数（UPF）达115.42,紫外线UVA（320420 nm）透过率为3.35%,接触角为156.54°,滚动角为8°,具有优异的抗紫外、超疏水性能。此外,处理棉织物经过24 h紫外线照射后,接触角仍为152.73°,滚动角仍可达到9°,实现了耐紫外线稳定性。
文摘In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.
