Structure and formation mechanism of carbon-doped titanium oxide nanotubes

碳掺杂氧化钛纳米管的结构及形成机理

• 批准号: 324158393
• 负责人: Professorin Dr. Uta Helbig
• 金额: --
• 依托单位: Fakultät Werkstofftechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/324158393?language=en
• 关键词: Structure; formation; mechanism; carbon; doped

Carbon-doped titanium oxide nanotubes are a promising material for several applications such as PEM fuel cells. The nanotubes have a high specific surface area, good electrical conductivity and, as first experiments showed, high oxidation stability.The tubes can be synthesized in alkaline solution via a hydrothermal process from titanium oxide. The oxide powder is transformed into multiwall nanotubes with typical inner diameters of 310 nm and a length up to 500 µm. An anatase-like structure or a titanate structure (H2Ti3O7) is suggested for the tubes. In connection with application, doping of as-produced tubes with various elements is reported in the literature including doping with carbon. The introduction of carbon is essential to achieve electrical conductivity. A common method for carbon doping is a temperature treatment in an acetylene/nitrogen gas flow. Application of this method on tubes leads to sintering and crystallization, however. As a result, only low amounts of tubes persist.To circumvent the disadvantages of thermal post processing, a new method was developed at TH Nürnberg. Instead of the tube material, the titanium oxide precursor powder is doped with carbon via carbothermal treatment. The tubes are synthesized in the hydrothermal process subsequently. The formation process of the tubes is discussed controversially up to now but of high interest for potential application. Therefore, the formation process will be investigated taking samples from the process after various time steps. The samples will be investigated regarding morphology, phase content and carbon incorporation. The information will be correlated with synthesis parameters like concentration of educts, pH value, temperature and duration.On the basis of the results regarding formation mechanism and carbon incorporation further optimization of the synthesis will be possible as a pre-requisite for application.

碳掺杂二氧化钛纳米管是一种很有前途的材料，可用于质子交换膜燃料电池等领域。纳米管具有高比表面积、良好的导电性和高的氧化稳定性。纳米管可以在碱性溶液中由氧化钛通过水热工艺合成。将氧化物粉末转变成典型的内径为310 nm、长度可达500微米的多壁纳米管，建议采用锐钛矿型结构或钛酸盐结构(H_2Ti3O_7)。在应用方面，文献中报道了用各种元素掺杂所生产的管子，包括用碳掺杂。碳的引入对于实现导电性是必不可少的。碳掺杂的一种常见方法是在乙炔/氮气气流中进行温度处理。然而，在管子上应用这种方法会导致烧结和结晶。为了克服热后处理的缺点，在纽伦堡开发了一种新的方法。通过碳热处理，在二氧化钛前驱体粉末中掺入碳，取代了管材。随后在水热过程中合成管子。管子的形成过程到目前为止还存在争议，但具有潜在的应用价值。因此，将在不同的时间步骤后从工艺中采集样品来研究形成过程。将对样品的形貌、物相含量和碳掺入进行研究。这些信息将与合成参数如排泄物浓度、pH值、温度和持续时间相关联。在关于形成机理和碳掺入的结果的基础上，进一步优化合成将是应用的先决条件。