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, SnO 2 @Graphene, WO 3 @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 NO 2 , CO 2 , and NH 3 molecules, 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 NO 2 and CO 2 for studying the cross-sensitivity and developing a calibration model. As a result, the NO 2 detection with different background levels of CO 2 was achieved with an R 2 of 0.987 and an RMSE of about 22 ppb.