Bismuth iodide@carbon nanotube nanohybrids for sensitive detection of low concentrations of benzene

The timely and accurate detection of volatile organic compounds (VOCs), particularly aromatic compounds such as benzene, toluene, and xylene, is critical for environmental monitoring and industrial safety. Benzene is a known carcinogen with strict exposure limits [Occupational Safety and Health Administration: 1 ppm 8 h—time-weighted average, 5 ppm short-term exposure limit; WHO guidelines: ∼17 μg/m3 (∼5.5 ppb) for 10−4 lifetime risk]. This study investigated the gas-sensing performance of bismuth iodide (BiI3)-carbon nanotube (DWNT) nanohybrids (BiI3@DWNT). The sensor demonstrated high sensitivity to benzene with response/recovery times of 35.2 and 73.3 s, respectively, and minimal cross-sensitivity to alkanes (hexane and hexadecane) under tested conditions. The enhanced performance is attributed to charge transfer effects, quantum confinement effects, and improved gas adsorption. Furthermore, the gas sensor operates efficiently at room temperature, making it an energy-efficient alternative. These findings highlight the potential of BiI3@DWNT nanohybrids as a promising platform for next-generation VOC sensors.