2D CO₃O₄ Nanosheets for High Selectivity and Response of H₂S Gas Sensing Performances

Abstract

As the demand for selective and sensitive gas sensors continues to escalate, the development of novel materials with enhanced performance becomes increasingly imperative. The present investigation delves into the fabrication and implementation of two-dimensional cobalt oxide (Co3O4) nanostructures as highly proficient gas sensors for the discerning identification of hydrogen sulfide (H2S) within intricate environmental circumstances. The distinct two-dimensional configuration of Co3O4, characterized by its substantial surface-to-volume ratio and abundant accessible active sites, markedly augments gas adsorption and reaction dynamics, resulting in exceptional sensitivity and selectivity toward H2S over other potentially confounding gases. Extensive characterization methodologies, encompassing X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), corroborate the successful synthesis of well-defined nanosheets. The materials exhibited optimal H2S detection at 250 °C, demonstrating significant sensitivity (Response = 214.45) and fast response and recovery times (16.85 s and 46.93 s, respectively). Its performance was further validated through concentration-dependent studies, which showed high accuracy even at low H2S concentrations (0.3–50 ppm). The sensor also displayed excellent selectivity for H2S over other gases, minimal interference from humidity, and maintained stability during cyclic exposure and long-term operation over 30 days. These findings highlight this material as a highly promising sensor for H2S detection due to its superior performance metrics. The incorporation of these nanosheets into a sensor apparatus offers a propitious strategy for the detection of low concentrations of H2S in real-world applications, such as environmental surveillance and industrial safety systems.