Decorated‐Induced Oxygen Vacancy Engineering for Ultra‐Low Concentration Nonanal Sensing: A Case Study of La‐Decorated Bi₂O₂CO₃

Abstract La‐decorated Bi₂O₂CO₃ (BCO‐La) microspheres are synthesized using a facile wet chemical strategy for sensing low‐concentration nonanal (C₉H₁₈O) at room temperature. These BCO‐La gas sensors are applied to evaluate agricultural product quality, specifically for cooked rice. The sensitivity of the BCO‐6La sensor significantly surpassed that of the pure BCO sensor, achieving a response value of 174.6 when detecting 30 ppm nonanal gas. Notably, the BCO‐6La sensor demonstrated a faster response time (36 s) when exposed to 18 ppm of nonanal. Additionally, the selectivity toward nonanal gas detection is higher (approximately 4–24 times) compared to interfering gases (1‐octanol, geranyl acetone, linalool, hexanal, 2‐pentyfuran, and 1‐octen‐3‐ol) during cooked rice quality detection. The gas sensing mechanism and the factors contributing to the enhanced sensing performance of the BCO‐La microspheres are demonstrated through in situ FT‐IR spectra and DFT analysis while the realistic detection scenario is carried out. In a broader context, the reported sensors here represent a novel platform for the detection and monitoring of gases released by agricultural products during storage.