Enhanced Acetic Anhydride Detection Based on ZnO/La₂O₃ Nanoparticles With High Selectivity and Sensitivity

Acetic anhydride is a crucial chemical composition for heroin synthesis and is also a hazardous volatile organic compound (VOC). Hence, the development of a reliable and sensitive chemical sensor for its detection is essential. In this study, ZnO/La2O3 nanoparticles were successfully synthesized via a simple one-step hydrothermal process to detect acetic anhydride. The surface morphology, composition, and microstructure of particles were thoroughly analyzed. The 0.2 at% La-ZnO-based gas sensor exhibits a maximum of 422 toward 100-ppm acetic anhydride at the optimal operating temperature of 300 °C. The synergistic catalysis between ZnO and La2O3 heterojunction solves the problem of low sensitivity of pure ZnO to acetic anhydride. The unique selectivity and the high sensitivity of sensors to acetic anhydride are associated with the Lewis acid–base interaction because of the enhanced Lewis base sites on the surface of sensing materials. Significantly, the gas-sensitive mechanism is elaborated, including the effect of heterojunction and oxygen vacancies, and the catalysis of La2O3. The most important thing is that the rapid detection of acetic anhydride has been realized, which is significant in curbing the spread of drugs.