Interface engineering of ZnSnO3-based heterojunctions for room-temperature methanol monitoring

Detecting methanol is of great importance in the organic synthesis industry. Herein, the effective utilization of ZnSnO3-based microstructures for room-temperature methanol monitoring was realized through a template-free approach. ZnSnO3-based heterojunctions with different structures and morphologies were successfully synthesized via regulating the molar ratio of Zn2+ and Sn4+ sources. And room-temperature sensing properties towards methanol were investigated. Among them, ZnO/ZnSnO3 hollow microcubes exhibited an outstanding sensing performance including a high sensitivity (10.16) and a response/recovery time (14/75 s) and a limit of detection (490 × 10–9) towards 5 × 10–6 methanol. Additionally, the synergistic effects of hollow structure with larger specific surface areas (42.277 m2·g−1), the construction of n–n heterojunctions formed at ZnSnO3 and ZnO interfaces, the high percentage of dissociative and chemisorbed oxygen are the main causes of the elevated sensing characteristics. Besides, the practical experiment demonstrated that ZnO/ZnSnO3 was capable of on-field monitoring methanol in the chemical reaction utilizing H2 and CO2 as raw materials. Moreover, with the help of density functional theory calculations, the enhanced sensing properties of ZnO/ZnSnO3 are due to the special tuning effects of Zn ionic sites on methanol adsorption.