DOI: https://doi.org/10.55373/mjchem.v28i2.258

Keywords: MoS₂, hydrogen sensor, optical fibre, optical sensing, chemical bath deposition, room-temperature

Abstract

Hydrogen gas (H₂) is an increasingly vital energy carrier, but its highly flammable nature demands reliable and selective sensing systems. In this study, an optical H₂ sensor was developed by coating two-dimensional molybdenum disulfide (MoS₂) thin films onto a side-polished plastic optical fibre (POF). The MoS₂ sensing layer was synthesized using the chemical bath deposition (CBD) method, producing nanostructured films with porous morphology (10–40 nm nanogranules) and good crystallinity as confirmed by XRD. The deposited MoS₂ layer adhered uniformly to the fibre surface, enabling strong interaction with the guided light through the exposed fibre core. Optical absorbance measurements revealed a clear, consistent response to H₂ concentrations (0.25–1.00 %), with a linear sensitivity of 0.3084 a.u./% H₂ (R² = 0.9476). The sensor exhibited rapid response times decreasing from 5 min at 0.25 % H₂ to 3 min at 1.00 % H₂, and recovery times between 5–7 min depending on concentration. These results confirm that nanostructured, crystalline MoS₂ coatings provide abundant active sites for H₂ adsorption, leading to fast and sensitive optical detection. This integration of CBD-grown MoS₂ with optical fibres demonstrates a promising pathway for low-power, electromagnetic interference (EMI) immune, and compact H₂ sensing applications.