Cubic Sm2O3-modified ZIF-8-derived ZnO in heterojunction type for ethanol sensors

Sm 2 O 3 -modified ZIF-8-derived ZnO nanoparticles were first prepared by a one-step hydrothermal method. • The maximum response to 100 ppm ethanol was 210 at the operating temperature (275 °C). • The reasons for the improved gas-sensitive performance were explored. Constructing heterojunctions is recognized as an effective strategy for enhancing gas sensor performance. Rare-earth metal oxides, owing to their unique properties, can significantly improve the sensing capability of single-metal oxides. This work produced a ZnO/Sm 2 O 3 heterostructure for ethanol gas sensing via a simple one-step hydrothermal method. A static system was used to investigate the gas-sensing properties of the as-prepared sensors. Compared with the pure ZnO sensor, the ZnO/Sm 2 O 3 heterojunction sensor exhibited a significantly enhanced sensing performance toward 100 ppm ethanol. Specifically, its response increased from 130 to 210, the optimal operating temperature decreased from 295 °C to 275 °C, and the recovery time was shortened from 84 s to 17 s. In addition, the sensor demonstrated good selectivity toward ethanol over other interfering gases, as well as excellent long-term stability, while maintaining good linearity and repeatability. The material was characterized using various techniques, including XRD, XPS, SEM, TEM, BET, UPS, and Hall-effect measurements, in terms of micromorphology, elemental composition and specific surface area, revealing cube-like structures and confirming the successful formation of an n-n heterojunction. Finally, the underlying mechanism for the enhanced gas sensing performance was discussed in detail. Download: Download high-res image (68KB) Download: Download full-size image