Pd/PMMA Nanocomposite-Coated Optical Fiber Hydrogen Sensor Operating at Room Temperature With Humidity Tolerance

A fiber-optic hydrogen sensor coated with a palladium/polymethyl methacrylate (Pd/PMMA) nanocomposite layer is fabricated and benchmarked here. The sensor with Pd/PMMA substituted cladding operates by intensity modulation technique through partial reflection in the sensing region. The in situ thermal reduction method has been adopted for nanocomposite synthesis due to the reduced processing steps required and to avoid material waste. Benefitting from the hydrogen selective response of Pd nanoparticles (NPs) and the filtering ability of the PMMA matrix, the sensor exhibits excellent resistance to humidity and good environmental stability in the presence of interfering gases. Furthermore, it can detect low hydrogen concentrations of down to 0.1%, shows suppressed hysteresis, and has a response time of 25 s to 4% hydrogen. All these features, combined with the feasible and cost-effective sensor preparation protocol, make the sensor a competitive candidate for hydrogen gas monitoring applications that operate at near room temperatures.