Surface Acoustic Wave Devices Based on Graphene Oxide/Au Nanorod Composites for Gas-Phase Detection of 2,4,6-Trinitrotoluene

Surface acoustic wave (SAW) devices are extensively used to detect various gaseous chemicals, owing to their wireless passive potential and single-signal display. However, the sensitivity, selectivity, and long response time of the sensitive layers limit their use in detecting explosive gases. In this study, we developed a 2,4,6-trinitrotoluene (TNT) gas sensor based on the SAW device with GO/PDEA/AuNR/PATP nanocomposites. The GO/PDEA/AuNR/PATP-SAW sensor recorded a considerable negative frequency shift (−70.67 kHz) in detecting 80 ppm TNT at 25 °C/20 RH %, thus enabling the detection of 40 ppb to 80 ppm TNT with the limit of detection as low as 40 ppb (−3.02 kHz). Short response/recovery time (40 ppb: 6.2/11.8 s) with good cycling stability and selectivity were achieved. The high performance of the GO/PDEA/AuNR/PATP-SAW sensor is attributed to its large specific surface area, roughness, and porosity. The oxygen-containing and electron-rich amino groups of the GO/PDEA/AuNR/PATP provide many active sites for adsorbing TNT gas. The primary sensing mechanism is the mass and electrical load of the nanocomposite in TNT gas. It has an optimum thickness of 380 nm and room temperature as the optimum operating temperature. Therefore, this study would serve as a good basis for the research and development of next-generation acoustic gas-phase explosive sensors.