Hydrogen (H₂) is a clean, sustainable, and highly energy efficient fuel source which will meet the increasing energy demand. Fuel cells can utilize H₂ and convert it into electric energy with high efficiency. However, the usage of fuel cells is limited by degradation of their performance by even trace levels of sulfur impurities (<100 ppb) present in H₂. Therefore, there is a vital need for trace level sulfur sensors to monitor the quality of H₂ fuel utilized in fuel cells. The present thesis demonstrates a novel chemical sensor using an indigenous sensing scheme: adsorbate–induced damping of hybrid plasmon resonance, associated with Ag nanoparticles, to detect ppb levels of sulfur impurities in H₂. The nanoparticles report the full width at half maximum (FWHM) or plasmon-damping factor through optical extinction. Subsequently, H₂S concentration is calculated using time rate of change of plasmon-damping factor in the initial linear regime.

Results have shown that the change in plasmon—damping factor related to sulfur adsorbates follows multiple Langmuir adsorption isotherms. Further, the time rate of change of plasmon-damping factor (i.e., slope) corresponding to first Langmuir isotherm in linear regime has shown a linear response to H₂S concentration. It is also revealed that the sensitivity and response time of the present sensor is strongly dependent on H₂S:H ₂ gas flow rate. The sensor has shown a low detection limit of 65 ppb H₂S:H₂, for which a response time of 10 s is observed, using a gas flow rate of 520 sccm.