A Graphene-Templated Epitaxial SnO ₂ /FDM-23 Ternary Composite for Rapid and Highly Sensitive Hydrogen Sulfide Detection

Achieving precise and real-time detection of trace hydrogen sulfide (H 2 S) and its related malodorous substances is essential for advancing a proactive prevention-oriented environmental governance model. However, metal-oxide-based H 2 S sensors often suffer from high operating temperatures, inadequate selectivity, and sluggish response/recovery times. In this study, we fabricate a ternary SnO 2 -doped graphene/FDM-23 (Fudan Material-23) epitaxial composite, which integrates SnO 2 nanoparticles into a graphene-epitaxial FDM-23 metal–organic framework (MOF) matrix, enabling ultrafast and sensitive H 2 S sensing at room temperature (25 °C). The sensor based on the composite demonstrates a 3.7% response to 1 ppm of H 2 S with response/recovery times of 3.9 s/7.6 s, and its calculated limit of detection (LOD) is as low as 6.9 ppb. Notably, the distinct response profiles of the sensor toward five similar volatile sulfur compounds (VSCs) are subjected to principal component analysis (PCA) for effective clustering, while support vector machine (SVM) classification achieves a high identification accuracy of 97.1%.