Research Of Carbon Nanotubes-based Gas Sensors And Volatile Organic Compounds Recognition

Carbon nanotubes are one-dimension nanomaterial with many particular properties. Their nano-size and high radio of surface proportion provide it to be promising gas sensitivity material. The paper mainly researched response of carbon nanotubes to volatile organic compounds (VOCs). The absorption of different gases on the carbon nanotubes layer changes the conductivity. We experimented on gas sensitive response of chemical modified carbon nanotube by adding amide-alkyl chain, doped with N elements and composite with poly-pyrrole. The gas sensitivity did not change significantly after the modification but were somewhat different, such as some are most sensitive to xylene; others are most sensitive to methanal.This paper also presented design of an electronic nose system based on gas sensors array and artificial neural network (ANN) for the identification of some (VOCs) relevant to environmental monitoring such as benzene, toluene; The sensors array consisted of the several modified carbon nanotubes-based sensors above. Principal component analysis (PCA) method was used for discussing the possibility of the sensors array for VOCs recognition and reduction of the dimensions for pattern recognition. Then designed the radial basis artificial (RBF) neural network by train and simulate the gas sensitivity data. A 100% accurate recognition ratio and a little error within 3 ppm by the interference of humidity were found by test experiment.The paper firstly introduced the structure, properties, preparation method and application of carbon nanotubes. Secondly electronic nose information was introduced. Thirdly the most important part was the gas sensitivity experiments. Next was the introduction of PCA and RBF ANN knowledge and then was the design work of the neural network including train, simulation and test. Finally the summarization and thanks were presented.