Pt-Functionalized SnO2 Hollow Nanotubular Structures for H2S Sensing: Experimental Investigation and DFT Insights

Pt-functionalized SnO2 hollow nanotubular structures were fabricated by single-nozzle electrospinning followed by calcination and evaluated for H2S sensing. At an operating temperature of 350 °C, the 2 wt% Pt/SnO2 sensor exhibited a response of 567.1 to 50 ppm H2S, which was 11.9 times higher than that of pristine SnO2. The sensor showed response and recovery times of approximately 1 and 150 s, respectively, an experimental detection limit of 200 ppb, as well as excellent selectivity, repeatability, and long-term stability. Experimental characterizations and DFT calculations indicated that the improved performance arises from the accessible gas-diffusion pathways of the hollow nanotubular structure, together with Pt-enhanced H2S adsorption and interfacial electronic modulation. In a proof-of-concept shrimp storage test, the sensor response changed consistently with pH, color difference, and sensory scores, with a marked response increase near the observed transition in freshness indicators. These findings demonstrate the potential of Pt/SnO2 HNTSs for H2S sensing and non-destructive shrimp freshness monitoring.