CuO nanowire gas sensors for air quality control in automotive cabin

CuO nanowires (NWs) were grown by the thermal oxidation of Cu foil at 400 °C and gas sensors were fabricated by the deposition of a solution containing the CuO NWs. At 300–370 °C, the sensor resistance increased upon exposure to 30–100 ppm CO. This has been explained by the gas sensing characteristics of the p-type oxide semiconductor. In contrast, the sensor showed two opposite NO2 sensing behaviors; the resistance decreased upon exposure to 30–100 ppm NO2, but increased upon contact with ≤5 ppm NO2. The increase in resistance upon contact with both reducing CO and a low concentration of oxidizing NO2 gases provides a simple and novel sensing algorithm for air quality control in automotive cabins.