CuO surface doped In2O3/CeO2 nanofibers for ppb-ppm level carbon monoxide gas detection in low-temperature

In this work, we designed and prepared CuO-loaded In2O3/CeO2 nanofiber heterojunctions, which are promising for trace CO gas detection. We characterized the materials, confirmed the morphology of the nanofibers and structure of the p-n heterojunctions, and analyzed the effect of morphology and structure on the gas sensing performance. In gas sensing tests, the sensor is found to show a low optimum operating temperature of 70 °C, with a limit of detection that reaches as low as 50 ppb. At concentrations ranging from 50 ppb to 10 ppm, the sensor shows a sensitive and linear response for CO gas. In particular, the sensor shows a response (Ra/Rg) of 11.7–10 ppm CO gas, and a response/recovery time of 125 s/12 s for 2 ppm CO gas. In addition, we tested the selectivity, humidity response and long-term stability of the gas sensors. Finally, based on the structure of the materials, we propose a mechanism for the enhanced CO gas sensing performance.