Room-Temperature QCM Sensor Based on GO@WO₃ Nanocomposites for Ammonia Detection

The detection of ammonia (NH₃) 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 WO₃ 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 NH₃, the sensor based on 1.5% GO@WO₃ nanocomposites achieved a frequency shift of 578 Hz, which was 6.4 times that of the pure WO₃ QDs sensor. The theoretical limit of detection (LOD) of the sensor was calculated to be 60 ppb, enabling ppb-level NH₃ detection. In addition, the sensor demonstrated good long-term stability over a two-week period. The enhanced performance of the GO@WO₃ nanocomposite sensor is attributed to the formation of an ohmic contact between GO and WO₃, 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 NH₃ detection, offering significant advantages over traditional single-component sensors.