Room-Temperature QCM Sensor Based on GO@WO(3) Nanocomposites for Ammonia Detection.

The detection of ammonia (NH) at room temperature is of significant importance for environmental monitoring, industrial safety and early disease diagnosis. In this work, a novel room-temperature ammonia sensor was developed by combining graphene oxide with WO quantum dots. The as-fabricated sensor exhibited excellent comprehensive sensing performance, including high sensitivity, rapid response, outstanding selectivity, and reliable long-term stability. Specifically, when exposed to 10 ppm NH, the sensor based on 1.5% GO@WO nanocomposites achieved a frequency shift of 578 Hz, which was 6.4 times that of the pure WO QDs sensor. The theoretical limit of detection (LOD) of the sensor was calculated to be 60 ppb, enabling ppb-level NH detection. In addition, the sensor demonstrated good long-term stability over a two-week period. The enhanced performance of the GO@WO nanocomposite sensor is attributed to the formation of an ohmic contact between GO and WO, which eliminates charge transfer barriers, promotes oxygen adsorption, and amplifies the sensing signal. This work provides a simple, efficient, and practical solution for room-temperature NH detection, offering significant advantages over traditional single-component sensors.