Enhanced sensitivity and selectivity of ammonia sensing by QCM modified with boric acid-doped PVAc nanofiber

Analysis of atmospheric ammonia gas is always challenging with the main issues are low selectivity and sensitivity. In this study, we devised a quartz crystal microbalance (QCM) method to detect ammonia gas in the air using electrospun polyvinyl acetate (PVAc) nanofiber that was doped with boric acid to obtain better ammonia sensing characteristics. The produced nanofiber was checked mainly by SEM-EDX and FTIR spectroscopy. The sensitivity of the PVAc/BA6 nanofiber QCM sensor was found to be 0.072 Hz/ppm, which was higher than that of the undoped one (0.044 Hz/ppm). Apart from the enhanced sensitivity, the PVAc/BA6 nanofiber sensor also showed good and enhanced selectivity towards ammonia gas detection. Doping PVAc nanofibers with boric acid proves to enhance both sensitivity and selectivity of ammonia gas sensing. This work could open a promising way to advance the sensitivity and selectivity of the QCM gas sensor modified with polymers doped with suitable compounds.