Enhancement of Ethanol Vapor Sensing of TiO2 Nanobelts by Surface Engineering
Enhancement of Ethanol Vapor Sensing of TiO2 Nanobelts by Surface Engineering
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DOI：
10.1021/am100707h
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发表时间：
2010-11-01
影响因子：
9.5
通讯作者：
Chen, Shaowei
中科院分区：
文献类型：
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作者：
Hu, Peiguang;Du, Guojun;Chen, Shaowei
采用水热法制备了TiO 2纳米带，并利用表面工程技术对其结构进行了调控，包括酸腐蚀法粗化表面和光还原法在TiO 2纳米带表面形成Ag-TiO 2异质结构。在不同的温度下，通过电导率测量来检查和比较它们在检测乙醇蒸气中的性能。在基于四种纳米带样品（TiO 2纳米带Ag-TiO 2纳米带、表面粗化TiO 2纳米带和表面粗化Ag-TiO 2纳米带）的传感器中，与基于其他氧化物纳米结构的传感器相比，它们都显示出改进的灵敏度选择性和用于乙醇蒸气检测的短响应时间。更重要的是，在TiO 2纳米带表面形成的Ag-TiO 2异质结构和TiO 2纳米带的表面粗化被发现导致传感器的灵敏度明显进一步增强，以及最佳工作温度的降低。也就是说，在本实验范围内，基于表面粗化的Ag-TiO 2复合纳米带的蒸汽传感器表现出最好的性能。传感机理解释的基础上的表面耗尽模型，和改善氧化物表面工程占的化学增感机制。本工作为一维氧化物纳米材料增强气敏性能提供了一种实用的方法。
TiO2 nanobelts were prepared by a hydrothermal process and the structures were manipulated by surface engineering, including surface coarsening by an acid-corrosion procedure and formation of Ag-TiO2 heterostructures on TiO2 nanobelts surface by photoreduction. Their performance in the detection of ethanol vapor was then examined and compared by electrical conductivity measurements at varied temperatures. Of the sensors based on the four nanobelt samples (TiO2 nanobelts Ag-TiO2 nanobelts, surface coarsened TiO2 nanobelts, and surface coarsened Ag-TiO2 nanobelts), they all displayed improved sensitivity selectivity, and short response times for ethanol vapor detection, in comparison with sensors based on other oxide nanostructures. Importantly, the formation of Ag-TiO2 heterostructures on TiO2 nanobelts surface and surface coarsening of TiO2 nanobelts were found to lead to apparent further enhancement of the sensors sensitivity as well as a decrease of the optimal working temperature. That is, within the present experimental context, the vapor sensor based on surface coarsened Ag-TiO2 composite nanobelts exhibited the best performance. The sensing mechanism was interpreted on the basis of the surface depletion model, and the improvement by oxide surface engineering was accounted for by the chemical sensitization mechanism. This work provided a practical approach to the enhancement of gas sensing performance by one-dimensional oxide nanomaterials.