Degradable LCNF/ZnO aerogel for ammonia sensing at room temperature

With the advancement of industrialization, the emission of toxic and harmful gases has become a significant threat to both environmental quality and human health. Gas sensors exhibit considerable potential in real-time monitoring of these hazardous substances. Given that lignin containing cellulose nanofibers (LCNFs) possess high mechanical strength, a large specific surface area, abundant surface functional groups, and excellent biocompatibility, they are promising substrates for gas sensing applications. In this study, LCNF/ZnO aerogels designed for NH₃ sensing were synthesized via a straightforward hydrothermal reaction followed by freeze-drying. Room-temperature sensing performance was enhanced by incorporating a small quantity of carbon nanotubes to improve the electronic conduction pathway. Experimental results indicate that the LCNF/ZnO composite aerogel exhibits rapid recovery time, specifically 22 s, with a response value reaching 4.94% at a room temperature concentration of 50 ppm ammonia. Moreover, the material demonstrates degradability. Buried in the ground, the aerogel substrate completely degrades within three weeks. The development of LCNF/ZnO composite aerogels not only expands the application scope of ZnO in real-time NH₃ monitoring at room temperature but also offers a novel approach towards green and sustainable utilization of LCNFs in gas sensing.