Porous CeO2 nanospheres for a room temperature triethylamine sensor under high humidity conditions

Abstract

The development of highly sensitive and selective gas sensors is essential for the detection of harmful compounds. However, the gas-sensing performance presents some challenging issues such as the requirement of high operating temperatures and the negative impact of humidity. Herein, we have prepared porous CeO₂ nanospheres (NS) using a simple microwave-assisted solvothermal method, followed by calcination, and demonstrated the triethylamine (TEA) sensing performance of the NS at room temperature and a relative humidity of 98%. The sensor showed enhanced sensing properties towards TEA compared to other volatile organic compounds. Significantly, the CeO₂ NS exhibited a response of 4.67 to 100 ppm of TEA with a fast response time of 13 s. Furthermore, the sensor was able to detect low TEA concentrations (5 ppm) and presented excellent repeatability. The outstanding sensing properties are attributed to the high specific surface area, the porous structure of CeO₂ NS (which allows a great gas diffusion), and the increased number of active sites for TEA oxidation due to the formation of hydroxyl groups on the CeO₂ surface from high humidity conditions. Thus, the use of CeO₂ NS is a promising approach by which to fabricate TEA sensors that operate at room temperature and high humidity levels.