Self-Powered Monitoring of Ammonia Using an MXene/TiO 2 /Cellulose Nanofiber Heterojunction-Based Sensor Driven by an Electrospun Triboelectric Nanogenerator.

Real-time monitoring of harmful gases is of great significance to identify the environmental hazards to people's lives. However, this application scenario requiring low-power consumption, superior sensitivity, portability, and self-driven operation of gas sensors remains a challenge. Herein, an electrospun triboelectric nanogenerator (TENG) is synthesized using highly electronegative and conducting MXene nanofibers (NFs) paired with biodegradable cellulose acetate NFs (CA-NFs) as triboelectric layers, which supports a sufficient power density (∼1361 mW/m 2 @2 MΩ) and shows a self-powered ability to operate the chemiresistive gas sensor fabricated in this work. Further, by using cellulose nanofibers (C-NFs) as a substrate, a new kind of MXene/TiO 2 /C-NFs heterojunction-based sensory component is developed for detection of NH 3 . This sensor exhibits excellent reproducibility, high selectivity, and sensitivity toward NH 3 (1-100 ppm) along with a fast response/recovery time (76 s/62 s) at room temperature. Finally, a monitoring system comprising a TENG-powered sensor, an equivalent circuit, and an LED visualizer has been assembled and successfully demonstrated as a fully self-powered device for NH 3 leakage detection. Thus, this work pushes forward the intelligent gas sensing network self-driven by human motion energy, dispensing the external battery dependence for environment monitoring to reduce the possible health effects.