(A) study on the synthesis of catalyst functionalized $WO_3$ nanofibers networks for exhaled breath gas analysis and their gas sensing characterization

Abstract

Human exhaled breath contains thousands of kinds of volatile organic compounds and some of these volatile organic compounds can be used as bio-marker of diseases. Therefore diagnostic method which is detecting bio-marker gases in our exhaled breath using gas sensor is investigated. Among the various gas sensors, especially metal oxide gas sensor is highlighted for daily health care device because it is cheap, easy to miniaturize, and real-time detectable. However, gas sensing characteristics such as response and selectivity should be improved to apply for exhaled breath gas sensor device. In this thesis, highly sensitive porous metal oxide nanofibers networks gas sensing active materials were synthesized by modified electrospinning method. Gas sensing properties were dramatically improved by increased surface area, catalytic effect, and effective decoration of catalyst. In addition, gas sensing mechanisms was demonstrated by various analysis tools. Possibility of applying the breath analysis sensor is verified by gas sensing testing in highly humid atmosphere which is similar with exhaled breath.