First-principles insights into the C₆N₇ monolayer as a highly efficient sensor and scavenger for the detection of...

The design of new gas sensors and scavengers of volatile organic compounds (VOCs) is desirable for VOC enriching, separation and utilization. Herein, first-principles methods were performed to investigate the potential of C₆N₇ monolayers as highly efficient sensors and scavengers for selective VOCs (toluene, benzene, vinyl chloride, ethane, methanal, acetone, ethanol, and acetaldehyde). The physisorption of toluene, benzene, acetone, ethanol, acetaldehyde, and methanal has relatively high adsorption strength and can significantly tune the electronic properties and work function (Φ) of the C₆N₇, indicating that the C₆N₇ monolayer is highly sensitive and selective to these VOC gases. In addition, the desorption time of benzene, acetone, ethanol, acetaldehyde, and methanal is about 3, 0.4, 2.0 × 10^-2, 3.0 × 10^-2, and 3.6 × 10^-5 s at 300 K, respectively, indicating that the C₆N₇-based sensor has high reusability at room temperature. The recovery time of toluene was about 7.8 × 10² s at 300 K, showing disposable toluene gas sensing of the monolayer. Our work confirms that the C₆N₇ monolayer as a resistance-type and Φ-type gas sensor and scavenger is highly sensitive, selective and reusable for VOCs (benzene, acetone, ethanol, acetaldehyde, and methanol), but is a disposable toluene gas sensor and scavenger at room temperature.