Effect of surrounding gas temperature on the morphological evolution of TiO_2 nanoparticles generated by laser ablation in tubular furnace
Effect of surrounding gas temperature on the morphological evolution of TiO_2 nanoparticles generated by laser ablation in tubular furnace
复制标题
周围气体温度对管式炉激光烧蚀生成TiO_2纳米粒子形貌演化的影响
DOI：
10.1007/s11051-011-0674-7
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Tsuji;M.
在管状炉中，在可控温度条件下，在氧气气氛中激光烧蚀钛靶，合成了氧化钛纳米颗粒。纳米颗粒的大小和形状随炉温的变化而变化。利用扫描迁移率粒度仪测量了基于迁移率的空气悬浮纳米颗粒的粒径分布，并利用扫描电镜分析了初级颗粒的粒径分布。室温激光烧蚀生成颗粒时，颗粒为气相团聚体，平均迁移直径为117 nm，初生颗粒平均直径为11 nm。当炉温提高到800℃时，初级颗粒直径从11 nm增加到24 nm。由于发现从靶上烧蚀的Ti蒸气的质量与炉温无关，因此这种颗粒的生长可能归因于在较高温度下轻度淬火导致的核数的减少。当温度高于1000℃时，由于烧结作用，迁移率直径突然下降，初生颗粒直径增大，在1200℃时迁移率直径与初生颗粒直径重合。由于激光烘箱法可以独立控制蒸汽浓度和周围大气温度，因此它是研究给定尺寸的初级颗粒形成纳米颗粒过程的有效工具。
Titanium oxide nanoparticles are synthesized by laser ablation of Ti target in oxygen atmosphere under well-controlled temperature profiles in a tubular furnace. The size and the shape of generated nanoparticles are varied by changing the temperature of furnace. The mobility-based size distributions of generated air-borne nanoparticles are measured using a scanning mobility particle sizer, and the size distributions of primary particles are analyzed by a scanning electron microscope. When the particles are generated by laser ablation at the room temperature, the particles are agglomerates in gas phase with the average mobility diameter of 117 nm and the mean diameter of primary particles of 11 nm. The primary particle diameter increases from 11 to 24 nm by raising the furnace temperature up to 800 °C. Since the mass of Ti vapor ablated from a target is found to be constant regardless of the furnace temperature, this particle growth may be attributed to the reduction in nuclei number as a result of mild quenching at higher temperatures. As the temperature reaches higher than 1,000 °C, the mobility diameter suddenly drops and the primary particle diameter increases due to sintering, and at 1,200 °C the mobility diameter coincides with the primary particle diameter. Since the laser oven method offers an independent control of vapor concentration and the temperature of surrounding atmosphere, it is an effective tool to study the formation process of nanoparticles from primary particles with a given size.