Oxygen vacancy engineering on cerium oxide nanowires for room-temperature linalool detection in rice aging

It is a huge challenge for metal oxide semiconductor gas sensors to inspect volatile organic compounds (VOCs) at room temperature (RT). Herein, the effective utilization of cerium oxide (CeO₂) nanowires for RT detection of VOCs was realized via regulating its surface chemical state. Oxygen vacancy engineering on CeO₂ nanowires, synthesized via hydrothermal method, can be manipulated by annealing under various controlled atmospheres. The sample annealed under 5%H₂+95%Ar condition exhibited outstanding RT sensing properties, displaying a high response of 16.7 towards 20 ppm linalool, a fast response and recovery time (16 and 121 s, respectively), and a low detection of limit of 0.54 ppm. The enhanced sensing performance could be ascribed for the synergistic effects of its nanowire morphology, the large specific surface area (83.95 m²/g), and the formation of extensive oxygen vacancy accompanied by an increase in Ce³⁺. Additionally, the practicability of the sensor was verified via two varieties of rice (Indica and Japonica rice) stored in various periods (1, 3, 5, 7, 15, and 30 d). The experimental results revealed that the sensor was able to distinguish Indica rice from Japonica rice. Accordingly, the as-developed sensor delivers a strategic material to develop high-performance RT electronic nose equipment for monitoring rice quality.