Excessive aging of paddy leads to flavor loss and a decrease in economic value, yet a standardized method for assessing the degree of aging is currently lacking. As a signature VOC in the aging process, the release concentration of 1-Octen-3-ol can serve as a physicochemical detection indicator. In this study, the ternary metal oxide CdIn₂O₄ was used as the gas-sensitive material and formed a heterojunction with NiO to achieve highly sensitive detection of 1-Octen-3-ol. Microscopic morphology indicates that the secondary solvothermal reaction facilitates the in situ growth of NiO nanosheets on CdIn₂O₄, optimizing the material's specific surface area. Results from the gas-sensitive testing indicate that the formation of the heterojunction significantly enhances the material’s sensitivity to 1-Octen-3-ol. At a NiO content of 10 at.%, the material exhibits optimal gas-sensitive performance, including a lower detection limit (135.3 ppb) and a superior response/ recovery times (107/125 s). Compared to other samples, the 10NiO/CdIn₂O₄ exhibits a higher response value (29.28 @ 25 ppm) under the same 1-Octen-3-ol concentration conditions, as well as excellent repeatability and response stability. The mechanism of sensitization of the heterojunction was elucidated by analyzing changes in band structures. Existence of the electron depletion layer and built-in electric field not only increases the rate of change in resistance and enhances the response value but also accelerates the electron-hole separation rate, optimizing the response time. The NiO/ CdIn₂O₄ prepared in this study exhibits good sensitivity and selectivity toward low concentrations of 1-Octen-3-ol, showing broad application prospects for standardizing paddy aging detection.
 

Gas sensor; Ternary metal oxides; CdIn2O4; Heterojunction; 1-Octen-3-ol; Aging