MOF-derived In2O3 nanotubes/Cr2O3 nanoparticles composites for superior ethanol gas-sensing performance at room temperature

Semiconductor metal oxide gas sensors have been frequently used for real-time monitoring of various gases in different applications. However, the working temperature is usually high (>150 degrees C), which limits their appli-cation. In this work, the composites of In2O3 nanotubes derived from metal-organic framework (MOF) and Cr2O3 nanoparticles were successfully prepared via solvothermal and impregnation method. The structure, surface morphology and elementary of In2O3/Cr2O3 composites were characterized. Due to the synergistic effects of unique hollow tube structure, large specific surface area and p-n heterojunctions, the In2O3/Cr2O3 composites sensor exhibits excellent ethanol sensing performance at room temperature, including high response under low concentration (less than 5 ppm), excellent selectivity, good repeatability, fast response/recovery time, and long-term stability. The sensing mechanism was discussed in detail. This work provides a feasible synthesis strategy to prepare metal oxide-based hybrid composites, which could be used for fabrication of gas sensor with low energy consumption and high response.

Automated summary

Semiconductor metal oxide gas sensors are commonly used for real-time monitoring of various gases. However, their working temperature is usually high, limiting their applications. In this study, In2O3 nanotubes derived from metal-organic framework (MOF) and Cr2O3 nanoparticles were successfully prepared as composites. The resulting sensor showed excellent ethanol sensing performance at room temperature due to the synergistic effects of its unique hollow tube structure, large specific surface area, and p-n heterojunctions. This work provides a feasible synthesis strategy for metal oxide-based hybrid composites, which can be used to fabricate gas sensors with low energy consumption and high response.