Surface acoustic device for high response NO2 gas sensor using p-phenylenediamine-reduced graphene oxide nanocomposite coated on langasite

In this study, we fabricated a surface acoustic wave (SAW) device using a langasite (LGS) substrate. The p-phenylenediamine-reduced graphene oxide (PrGO)-coated LGS substrate resulted in high response sensor systems for very short time scale detection of NO2 and CO. With the catalytic reaction of PrGO, the resonant frequency of 100 ppm of NO2 gas changed by similar to 3.50 kHz, which is nearly eight times higher than that of the pristine LGS SAW device. Further, we conducted selectivity tests for NO, NH3, H2S, and CO gases; the results showed that the PrGO-coated LGS had higher selectivity for NO2 compared to other gases. Accordingly, the underlying mechanism for the superior NO2 sensing was discussed in relation to the morphological characteristics and configuration of PrGO. In addition, the effect of humidity on the SAW performance was studied under ambient NO2.

Automated summary

In this study, a SAW device using LGS substrate coated with PrGO was fabricated, showing high sensitivity for detecting NO2 and CO in a short time scale. The PrGO-coated LGS demonstrated higher selectivity for NO2 compared to other gases and the superior sensing mechanism was discussed in relation to the morphological characteristics and configuration of PrGO. Additionally, the effect of humidity on the SAW performance under ambient NO2 was studied.