Metal loaded nano-carbon gas sensor array for pollutant detection

Many research works report a sensitive detection of a wide variety of gas species. However, their in-lab detection is usually performed by using single gases and, therefore, selectivity often remains an unsolved issue. This paper reports a four-sensor array employing different nano-carbon sensitive layers (bare graphene, SnO₂@Graphene, WO₃@Graphene, and Au@CNTs). The different gas-sensitive films were characterised via several techniques such as FESEM, TEM, and Raman. First, an extensive study was performed to detect isolated NO₂, CO₂, and NH₃molecules, unravelling the sensing mechanism at the operating temperatures applied. Besides, the effect of the ambient moisture was also evaluated. Afterwards, a model for target gas identification and concentration prediction was developed. Indeed, the sensor array was used in mixtures of NO₂and CO₂for studying the cross-sensitivity and developing a calibration model. As a result, the NO₂detection with different background levels of CO₂was achieved with anR²of 0.987 and an RMSE of about 22 ppb.