Passive and wireless NFC tag-type trimethylamine gas detection based on WO3/MXene composite sensors

In this paper, we developed a high-sensitive WO3/MXene composite based gas sensor. The morphology, crystal structure, and chemical composition of the pure WO3, MXene and WO3/MXene composite were analyzed by several characterization means include SEM, XRD, and XPS, proving that the successful synthesis of WO3 nanoparticles, MXene nanosheets and WO3/MXene composites. The trimethylamine sensing element was fabricated by spin coating the prepared sensitive materials on the interdigital electrodes. The gas-sensing performance of the sensor was investigated at 25 oC, 23% RH, and the results demonstrate that the WO3/MXene based sensor has excellent response (Ra/Rg = 277.78 @10 ppm), fast response/recovery time (2 s/3 s @ 2 ppm) towards trimethylamine. It also holds excellent repeatability, selectivity, short-term and long-term stability. As a result, we have found that the addition of MXene has greatly improved the performance of WO3 for trimethylamine detection at room temperature. Finally, a tag-type gas detection device based on NFC technology has been developed to achieve detection. When testing, we only need to place a sensor label without power supply in the gas environment, and the non-contact testing can be realized outside. This work presents a novel, safe method for realizing hazardous gas detection.