CeO2/In2O3 Hollow Nanosphere Heterojunction for Real-Time CO Monitoring under High Humidity

Real-time monitoring of carbon monoxide (CO) is crucial for ensuring human safety. However, the accuracy of the CO detection is significantly diminished by high ambient humidity. This study focuses on synthesizing CeO2/In2O3 hollow nanospheres with varying CeO2 contents (0, 1, 2, 3 mol %) using a two-step method. Testing under different humidity conditions demonstrates that incorporating CeO2 not only amplifies the response rate of pure In2O3 sensors (from 1.4 to 1.65 at 100 ppm of CO) but also curtails the response and recovery times (from 11 s/27 s to 6 s/23 s) at 280 °C. Furthermore, CeO2/In2O3 composite sensors exhibit improved selectivity, repeatability, and long-term stability. Notably, the robust CO detection performance under high humidity verifies that the fabricated CeO2/In2O3 sensors can monitor CO in humid environments. The enhanced performance stems from the unique hollow structure, abundant mesopores on the surface, and the heterojunction between CeO2 and In2O3.