Grain boundaries dependent hydrogen sensitivity in MAO-TiO2 thin films sensors
Grain boundaries dependent hydrogen sensitivity in MAO-TiO2 thin films sensors
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DOI：
10.1016/j.snb.2010.05.014
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发表时间：
2010-06
影响因子：
8.4
通讯作者：
F. Ren;Liang Huang;Yun-han Ling;Jiayou Feng
中科院分区：
文献类型：
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作者：
F. Ren;Liang Huang;Yun-han Ling;Jiayou Feng
采用微弧氧化法在钛基体上制备锐钛矿型TiO 2薄膜，并对其氢敏特性进行研究。所获得的膜在250°C下表现出最大的H2气体响应，但在高于300°C的温度下没有显示出响应。利用电化学阻抗谱（EIS）研究了该传感器的气敏机理.对所制备的MAO-TiO 2薄膜进行的电化学阻抗谱分析表明，晶粒和晶界的等效电子传递回路分别由电阻和恒相元件（CPE）并联组成，并提出了一种可能的表面控制气敏机理.结果表明，晶界的温度依赖性是决定气敏性能的关键因素。
Anatase TiO2thin films were fabricated on titanium substrates by micro-arc oxidation (MAO) process and their hydrogen sensing properties were investigated. The obtained films exhibited the maximum H2gas response at 250°C but showed no response at the temperature above 300°C. Electrochemical impedance spectroscopy (EIS) was applied to investigate the gas sensing mechanism. EIS analysis on the as-prepared MAO-TiO2films with limited porosity reveals that the equivalent electron transfer circuit of grain and grain boundary could be represented electrochemically by a resistor and a constant phase element (CPE) in parallel, respectively, by which a possible surface-controlled gas sensing mechanism is proposed. It is found that temperature dependent grain boundary is a crucial factor governing the gas sensing properties.