Large-Surface-Area Bi2Sn2O7 Quantum Dots for Room-Temperature 1-Octanol Sensing: A Combined Experimental and Density Functional Theory Study

Chemiresistive gas sensors designed for the detection of agricultural volatile organic compounds (VOCs) play a crucial role in monitoring crop growth and ensuring the quality of agricultural products. However, conventional metal oxide gas sensors continue to encounter challenges related to high power consumption and limited detection capabilities. In this study, bismuth stannate oxide Bi2Sn2O7 (BSO) quantum dots were synthesized via a hydrothermal method to facilitate room-temperature detection of 1-octanol. A systematic investigation was conducted to elucidate the relationship between the gas sensing performance of the material and its microstructure, surface valence states, and electronic structure. The BSO-8 sensor, characterized by an exceptionally high specific surface area (BET = 143.57 m2 g−1), demonstrated a wide detection range of 1−50 ppm, exhibiting a remarkable response of 75.06 ± 1.25 at 50 ppm under 30% relative humidity. Additionally, the sensor displayed excellent reproducibility, long-term stability, and significant selectivity toward 1-octanol. Further mechanistic insights were obtained through valence band spectroscopy and density functional theory calculations, which provided a comprehensive understanding of the evolution of the electronic structure and gas adsorption behavior. These findings demonstrate the potential of BSO-based sensors for practical applications in detecting 1-octanol at 30% RH, highlighting its significance as a key biomarker for agricultural VOCs.