Moisture-Independent Detection of n-Propanol Using a Kinetic Gas Sensor Based on CdS Nanorods Coated with Reduced Graphene Oxide

Abstract

In the era of intelligent big data with the rapid expansion of information, real-time detection is becoming an essential criterion for evaluating gas sensors. It is of great significance for the rapid and precise detection of hazardous volatile gases such as n-propanol. In this study, the nanorod-like semiconductor metal sulfide CdS coated with reduced graphene oxide (rGO) nanosheets was utilized to construct a high-performance sensor capable of ultrarapid and accurate n-propanol detection. The sensor based on the CdS/rGO nanocomposite with 0.5 wt% rGO (CG-5) exhibited only 1 s for both response and recovery time to 100 ppm n-propanol, which were shortened by 13 and 2 times compared to pristine CdS, respectively. Meanwhile, the sensor response of CG-5 enhanced 3-fold that of pristine CdS. Additionally, the hydrophobic rGO component in the hybrid endowed the sensor with a strong moisture-interference resistance over 20–98% relative humidity. The excellent selectivity, repeatability, and long-term stability for n-propanol detection were demonstrated as well. The exceptional enhancement in the sensing performance of CG-5 can be ascribed to several contributing factors, including its geometric configuration, weakened hydrophilicity, lowered activation energy, and additional active sites at the heterointerface between CdS and rGO. The rational design of CG-5 made it a promising candidate for the rapid, sensitive, and reliable detection of n-propanol.

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“…As a p-type rGO semiconductor with highly attractive features, such as rich specific active sites and a strong adsorption ability to gas molecules, such as nitrogen dioxide and ammonia, rGO plays a critical role in the gas-sensing processes of hybrid sensing composites. 44,45,47,48,50–54…”