Investigation on microstructure and nonanal sensing properties of hierarchical Sb2WO6 microspheres

Various metal oxides with unique microstructures have been hopeful in fabricating gas sensors applications. This paper reports the room-temperature sensing properties of hierarchical Sb2WO6 (antimony tungstate) microspheres for nonanal, which is a dominant aromatic aldehyde compound in cooked rice. The hierarchical Sb2WO6 microspheres were obtained by pH control (from pH 1 to 5) through a one-step hydrothermal reaction. The experiment indicated that the optimal response of the Sb2WO6 (pH = 4) gas sensor to 30 ppm nonanal reached 62 at room temperature, which was about 8 times that of Sb2WO6 (pH = 1). The improved sensing performance resulted from the finer microstructure and larger specific surface area of Sb2WO6 with a pH value of 4, providing abundant adsorption sites for nonanal molecules. Meanwhile, the practicability of cooked rice stored for various periods was verified through gas detection, and the results indicated that the sensor might recognize the deterioration of cooked rice and ready-to-eat rice. Therefore, the as-prepared sensor can be used in electronic nose systems to detect cooked rice and ready-to-eat rice deterioration and improve rice cooking methods.