Triboelectric nanogenerator based on ZIF-8/ZIF-67/CF composites for self-powered HCHO sensing and indoor environmental monitoring

ZZP-TENGs are designed for monitoring the HCHO concentration with high-pressure gas streams. • ZZP-TENG exhibited excellent sensing performance of HCHO. • ZZP-TENGs can be employed to construct an HCHO early warning system. • ZZP-TENG is applicable for detecting changes in indoor HCHO concentration. Formaldehyde (HCHO), a hazardous volatile organic compound, poses serious threats to human health in daily life and industrial environments. Herein, a pulse airflow-driven triboelectric nanogenerator (ZZP-TENG) with a ZIF-8/ZIF-67/copper foam composite microstructure was fabricated for high-sensitivity HCHO detection. Benefiting from micro/nano structural modification, the ZZP-TENG efficiently harvested ambient mechanical energy, yielding a short-circuit current of 3.62 μA and a maximum output power of 45.63 μW. Its stable energy output could drive 54 LEDs and charge various capacitors, demonstrating reliable energy-harvesting capacity. The sensor exhibited an 80% response toward HCHO at 40 ppm, along with a 30 s response time and an 80 s recovery time at 20 ppm. To verify practical indoor application feasibility, a simulated post-renovation HCHO release scenario was constructed with HCHO-containing wood blocks, supporting accurate indoor air quality assessment and environmental safety evaluation. In this study, an improved extreme learning machine (ELM) algorithm was employed to classify HCHO signals from the ZZP-TENG sensor. The ELM model realized 100% HCHO concentration recognition accuracy and constructed a three-level safety early warning system, achieving real-time intelligent indoor HCHO monitoring. This work realizes simultaneous airflow energy harvesting and HCHO detection, providing a novel route for integrated gas sensors and broadening the application of TENGs in self-powered indoor environmental monitoring. After the decoration of indoor residential and office spaces, formaldehyde (HCHO) is continuously released from building materials, furniture, and coatings, posing a serious threat to human health due to its chronic toxicity and carcinogenicity. When HCHO accumulates beyond the safe threshold, it causes eye irritation, respiratory inflammation, and long-term immune system disorders. In this study, a pulse airflow-driven triboelectric nanogenerator (ZZP-TENG) with a ZIF-8/ZIF-67/copper foam composite microstructure was fabricated for high-sensitivity HCHO detection. The self-powered device efficiently harvested ambient mechanical energy and delivered sufficient electrical output for continuous sensing. By integrating with a machine learning framework, the system achieved precise and graded evaluation of dynamic formaldehyde concentration throughout a six-week natural attenuation process. Furthermore, the integrated wireless alarm system enables real-time risk warning once pollutants exceed the safety threshold, realizing intelligent, long-term, and safe indoor air quality monitoring for residential and office environments. Download: Download high-res image (182KB) Download: Download full-size image