A self-powered gas sensor based on PDMS/Ppy triboelectric-gas-sensing arrays for the real-time monitoring of automotive exhaust gas at room temperature

A new self-powered active gas sensor for real-time monitoring of automotive exhaust gas was devised. The pipe-shaped device was fabricated from polydimethylsiloxane/polypyrrole (PDMS/Ppy) triboelectric gas-sensing unit arrays. The gas-sensing units can actively convert the mechanical energy of gas flow into a triboelectric current. The output current signal depends on the species and concentrations of the target chemical gases (CO, NH3, NO) in the gas flow, and thus can be used as a sensing signal. The device consists of seven gas-sensing units with different Ppy derivatives. As the different sensing units respond to the gases in different ways, the device can differentiate between gas species. The working mechanism is attributed to the coupling effect between the triboelectric effect of PDMS/Ppy and the gas-sensing properties of Ppy. The device can be installed in the tailpipe of an automobile, and can thus analyze the exhaust gas in real time without the need for any external electrical power. The results of the present study spur a new research direction for the development of automotive exhaust gas monitoring systems, thus playing an important role in the detection of air pollution.