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
草果为姜科植物草果(Amomum tsao-ko Crevost et Lemaire)的干燥成熟果实.主要产于云南、广西、贵州等地.草果的果实除作药用外,还是著名的香料和调味品.对于草果挥发油化学成分的分析虽已有报道,但对云南及广西产草果采用超临界CO2萃...草果为姜科植物草果(Amomum tsao-ko Crevost et Lemaire)的干燥成熟果实.主要产于云南、广西、贵州等地.草果的果实除作药用外,还是著名的香料和调味品.对于草果挥发油化学成分的分析虽已有报道,但对云南及广西产草果采用超临界CO2萃取法提取挥发油,并对其化学成分进行分析、比较,目前笔者尚未见报道.本实验采用了超临界流体萃取技术(SFE-CO2)分别提取了云南及广西产草果挥发油,用气相色谱-质谱联用技术检测了挥发油的化学成分.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.
文摘草果为姜科植物草果(Amomum tsao-ko Crevost et Lemaire)的干燥成熟果实.主要产于云南、广西、贵州等地.草果的果实除作药用外,还是著名的香料和调味品.对于草果挥发油化学成分的分析虽已有报道,但对云南及广西产草果采用超临界CO2萃取法提取挥发油,并对其化学成分进行分析、比较,目前笔者尚未见报道.本实验采用了超临界流体萃取技术(SFE-CO2)分别提取了云南及广西产草果挥发油,用气相色谱-质谱联用技术检测了挥发油的化学成分.
