Control of Phase and Pore Structure of Titania Powders Using HCl and NH4OH Catalysts
Control of Phase and Pore Structure of Titania Powders Using HCl and NH4OH Catalysts
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使用 HCl 和 NH4OH 催化剂控制二氧化钛粉末的相和孔结构
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
S. Pratsinis
中科院分区：
文献类型：
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作者：
K. Song;S. Pratsinis
以四异丙醇钛为原料，采用水解法制备了多孔二氧化钛粉体，并通过氮气吸附、X射线衍射和显微镜等手段对不同煅烧温度下的多孔二氧化钛粉体进行了表征。研究了水解过程中加入的HCl或NH 4 OH催化剂对二氧化钛粉末的结晶度和孔隙率的影响。盐酸促进了二氧化钛粉体从无定形到金红石以及从金红石到金红石的相变，而氨水则阻碍了这两种相变。在500°C下煅烧的二氧化钛粉末显示出双峰孔径分布：一个是平均孔径为3-6 nm的内部聚集孔，另一个是平均孔径为35-50 nm的相互聚集孔。平均聚集体内孔径随HCl浓度的增加而减小，随NH 4 OH浓度的增加而增大。
Porous titania powders were prepared by hydrolysis of titanium tetraisopropoxide (TTIP) and were characterized at various calcination temperatures by nitrogen adsorption, X-ray diffraction, and microscopy. The effect of HCl or NH4OH catalysts added during hydrolysis on the crystallinity and porosity of the titania powders was investigated. The HCl enhanced the phase transformations of the titania powders from amorphous to anatase as well as anatase to rutile, while NH4OH retarded both phase transformations. Titania powders calcined at 500°C showed bimodal pore size distributions: one was intra-aggregated pores with average pore diameters of 3–6 nm and the other was interaggregated pores with average pore diameters of 35–50 nm. The average intra-aggregated pore diameter was decreased with increasing HCl concentration, while it was increased with increasing NH4OH concentration.