Intelligent Gas Detection: g-C<sub>3</sub>N<sub>4</sub>/Polypyrrole Decorated Alginate Paper as Smart Selective NH<sub>3</sub>/NO<sub>2</sub> Sensors at Room Temperature
Junxuan Liang, Zongsheng Zou, Zhihui Zhao, Bin Hui, Weiliang Tian, Kewei Zhang
Abstract
Chemiresistive NH 3 /NO 2 sensors are attracting considerable attention for use in air-conditioning systems. However, the existing sensors suffer from cross-sensitivity, detection limit, and power consumption, owing to the inadequate charge-transfer ability of gas-sensing materials. Herein, we develop a flexible NH 3 /NO 2 sensor based on graphitic carbon nitride/polypyrrole decorated alginate paper (AP@g-CN/PPy). The flexible sensor can work at room temperature and exhibits a positive response of 23–246% and a negative response of 37–262% toward 0.1–5 ppm of NH 3 and NO 2, which is ∼4.5 times and ∼7.0 times higher than a pristine PPy sensor. Moreover, the sensor exhibits flexibility, reproducibility, long-term stability, anti-interference, and high resilience to humidity, indicating its promising potential in real applications. Using the 9 feature parameters extracted from the transient response, a matched deep learning model was developed to achieve qualitative recognition of different types of gases with distinguished decision boundaries. This work not only provides an alternative gas-sensing material for dual NH 3 /NO 2 sensing but also establishes an intelligent strategy to identify hazardous gases under an interfering atmosphere.