MOF-derived Al3+-doped Co3O4 nanocomposites for highly n-butanol gas sensing performance at low operating temperature

Abstract

High-performance gas sensors based on metal oxides for detecting Volatile Organic Compounds (VOCs) at low operating temperatures have garnered considerable attention due to their practical utility and energy efficiency. In this study, we synthesized the Al/Co metal-organic framework (MOF) by using a hydrothermal method. Subsequently, Al3+-doped Co3O4 (Al3+-Co3O4) nanocomposites with varying Al3+ concentrations were obtained through calcination. When applied to gas sensors, the Al3+-Co3O4 nanocomposites-based gas sensors exhibited excellent sensing properties toward n-butanol at a low operating temperature (100 ℃). Specifically, the response of the 10% Al3+-Co3O4 nanocomposite to 20 ppm n-butanol reached 116.7, representing an approximately 5.5-fold improvement compared to pristine Co3O4. The gas sensor based on the 10% Al3+-Co3O4 nanocomposite also demonstrated commendable repeatability, selectivity, and stability. This suggests that Al3+ doping results in Al3+-Co3O4 possessing a more intact spherical morphology. Doping significantly enhances the gas-sensing performance of Al3+-Co3O4 due to increased oxygen vacancies and a narrower band gap energy. These findings inspire the development of new p-type metal oxide semiconductor gas sensors operating at low temperatures.