Nitrogen-Doped Activated Carbon-Based Ammonia Sensors: Effect of Specific Surface Functional Groups on Carbon Electronic Properties

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• 作者：Nikolina A. Travlou ; Christopher Ushay ; Mykola Seredych ; Enrique Rodríguez-Castellón ; Teresa J. Bandosz
• 刊名：ACS Sensor
• 出版年：2016
• 出版时间：May 27, 2016
• 年：2016
• 卷：1
• 期：5
• 页码：591-599
• 全文大小：629K
• ISSN：2379-3694

文摘

Wood-based commercial activated carbon (BAX) and its oxidized counterpart (BAX-O) were treated with melamine and then heated at 450 °C in nitrogen. Further oxidation with nitric acid was also applied. The carbons were tested for ammonia sensing (45–500 ppm of NH₃). Even though all samples exhibit p-type conduction, their exposure to NH₃ led to different electrical outcomes. It was found that the electronic and transport properties of the carbons strongly depend on the type of nitrogen groups/surface defects, their concentration, and distribution in the carbon matrix. Pyridines and nitropyridines are the most important. A competition between the structural and chemical features of the carbons as those governing the sensing signals was observed. Exposure to ammonia altered the surface chemistry of the samples, and therefore their electrical properties. When sensitivity to H₂S was tested to evaluate the selectivity of our sensors, the results showed that the chips are selective to NH₃ in terms of the response time and magnitude of the signal changes.