IMPROVED SURFACE ACOUSTIC WAVE SENSOR FOR LOW CONCENTRATION AMMONIA/METHANE MIXTURE GASES DETECTION

In this research, we used the surface acoustic wave (SAW) sensor to detect chemical compounds such as ammonia, methane, and ammonia-methane mixture gases. Very low concentration of ammonia (～250 ppb) and methane (～9 ppm) can be detected by our SAW devices. And we used mesoporous carbon hollow nanosphere in Poly-N-vinylpyrrolidone (PNVP) film to increase the sensitivity to ammonia from 6.91 to 19.47 Hz/ppm. Besides, the signal loss is less than 6% after 17 detection cycles. Finally, we compared the response of ammonia and methane with ammonia/methane mixtures, finding synergy effect between these different gases by PNVP sensing film.