Formation of Nanoporous Bi2Se3 by Selenization of Bismuth Metal–Organic Frameworks for Highly Sensitive and Selective NO2 Sensing at Room Temperature

The development of high-performance and low-operating-temperature gas sensors is critical for real-time environmental and industrial process monitoring applications. In this study, we report the synthesis and application of a bismuth-based metal–organic framework (Bi-MOF)-derived Bi2Se3 sensor for the detection of NO2 at room temperature. Bi2Se3 was synthesized through a controlled selenization process that resulted in synergistic effects between Bi-MOF and Bi2Se3. The changes in morphology and surface physicochemical properties caused by the selenization process led to the tunability of the NO2 gas sensing properties. The Bi-MOF-derived Bi2Se3 sensitive materials were characterized using XRD, SEM, transmission electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, and BET to analyze their morphology, composition, pore structures, intensity of Se vacancies, and surface properties. The gas sensing performances were assessed under various NO2 concentrations, evaluating the sensitivity, selectivity, and resistance to humidity. Our findings show that the Bi2Se3 sensor exhibits excellent sensitivity and selectivity toward NO2 at room temperature. The best sensor showed a response of 32.1% toward 0.5 ppm of NO2 with a response/recovery time of 60.1/365.4 s, making it a promising candidate for NO2 monitoring. This study provides significant insights into the potential of Bi-MOF-derived Bi2Se3 materials in gas sensing, laying the groundwork for further research to optimize these sensors for practical applications.