Self-powered air purifier with coupling of non-thermal plasma and photocatalytic oxidation for formaldehyde degradation based on triboelectric nanogenerator

The emission of various volatile organic compounds (VOCs) caused by indoor decoration and furniture placement are the causes of health hazards in people's lives. Here, we demonstrate a self-powered air purifier for indoor organic pollutant removal based on triboelectric nanogenerator (TENG), coupling non-thermal plasma (NTP) with photocatalytic oxidation (PCO). An adjustable external high voltage field is generated by our homemade TENG, in which the output open-circuit voltage (Voc) ranges from 10 to 30 kV. After connecting the TENG with a non-thermal plasma generator (NTP-G), a maximum ozone concentration of 14.7 mg/m³ and NTP can be generated. The prepared three-dimensional porous framework is used as a photocatalytic layer, which can support more titanium oxide and increase the contact area between the photocatalyst and formaldehyde. This designed self-powered air purifier can reduce the formaldehyde concentration from 2.06 ppm to 0 ppm in 21 min in a 13 L closed air chamber. The design and concept proposed in this work has multiple ways for formaldehyde degradation and are not limited by sunlight, and can remove indoor formaldehyde around the clock, providing an effective way to create a cleaner and healthier indoor environment.