Synthesis of TiO2 nanoparticles with pure brookite at low temperature by hydrolysis of TiCl4 using HNO3 solution
Synthesis of TiO2 nanoparticles with pure brookite at low temperature by hydrolysis of TiCl4 using HNO3 solution
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DOI：
10.1007/s10853-005-2152-z
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发表时间：
2006
影响因子：
4.5
通讯作者：
J. Lee;Y. Yang
中科院分区：
文献类型：
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作者：
J. Lee;Y. Yang
纳米晶材料由于其特殊的化学、物理和机械性能而受到广泛关注。在这些材料中，纳米二氧化钛引起了极大的兴趣，因为它表现出许多改性的电子和光学性质以及广泛的应用，包括纳米和光电化学太阳能电池[1-4]。二氧化钛有三种天然存在的多晶型物：金红石、金红石和板钛矿。金红石和金红石相是众所周知的，并且已经报道了关于它们的合成和应用的许多研究[1，5-8]。然而，据报道，没有金红石或金红石相的混合物的纯板钛矿型TiO 2难以制备，并且难以制备具有高纯度和大表面积的板钛矿可能是其应用受限的原因之一[3，10]。最近，已经通过水热法合成了纯板钛矿型TiO 2颗粒，其中需要具有高温和高压的高压釜以及络合剂[2-4，10]。其他研究人员报告说，板钛矿有时被观察到作为一个副产品时，沉淀是在酸性介质中进行低温[2，7，10，11]。因此，我们描述了一种相对简单的方法，导致纯板钛矿型二氧化钛纳米粒子的合成，而无需添加络合剂在低温下。以TiCl 4为起始原料，采用不同浓度的HNO 3溶液水解TiCl 4，在60 ℃ ~ 150 ℃的温度范围内加热即可得到TiO 2纳米颗粒，并研究了由TiCl 4水溶液制备纯板钛矿型TiO 2颗粒的反应条件。制备纳米晶TiO 2颗粒的典型程序如下。通过滴加1.0M HNO 3使TiCl 4水解以制备储备溶液，其中钛的浓度为5.45M。在反应过程中，首先形成TiO（OH）2的黄色饼状物，然后将其用添加的HNO 3溶液溶解以形成TiCl 4水溶液。该储备溶液即使在室温下6个月后仍保持稳定状态而没有沉淀。最后，HNO 3溶液
Nanocrystalline materials are currently receiving much attention by virtue of their special chemical, physical, and mechanical properties. Of these materials, nanosized titanium dioxide has been of great interest because it exhibits many modified electronic and optical properties as well as extensive application, including photocatalysis and photoelectrochemical solar cells [1–4]. Titania has three naturally occurring polymorphs: rutile, anatase, and brookite. The rutile and anatase phases are well known and many studies on their synthesis and application have been reported [1, 5–8]. However, it has been reported that pure brookite-type TiO2 without a mixture of rutile or anatase phase is difficult to prepare and the difficulty in preparing brookite having high purity and large surface area is probably one of the reasons for its limited application [3, 10]. Recently, pure brookite-type TiO2 particles have been synthesized by hydrothermal method, in which the autoclave with high temperature and pressure as well as complexing agents are required [2–4, 10]. Other researchers reported that brookite is sometimes observed as a by-product when the precipitation is carried out in an acidic medium at low temperatures [2, 7, 10, 11]. We therefore describe a relatively simple method that leads to synthesis of pure brookite-type TiO2 nanoparticles without adding complexing agents at low temperature. In this study, TiCl4 used as a starting material was hydrolyzed using HNO3 solutions with various so that TiO2 nanoparticles could be obtained by merely heating it at temperatures ranging from 60◦ C to 150◦ C, from that reaction condition for the formation of pure brookite-type TiO2 particles from aqueous TiCl4 solution was investigated. A typical procedure for making nanocrystalline TiO2 particles was as follows. TiCl4 was hydrolyzed by adding 1.0 M HNO3 dropwise to prepare a stock solution, in which the concentration of titanium was 5.45 M. During the reaction, the yellow cakes of TiO (OH) 2 were formed first, which were then dissolved with added HNO3 solution to form an aqueous TiCl4 solution. This stock solution remained in a stable state without precipitation even after 6 months at room temperature. Finally, HNO3 solution