Sapphire Fiber Optical Hydrogen Sensors for High-Temperature Environments

This letter presents a high-temperature fiber optical hydrogen sensor with operational temperatures up to 800 °C. The sensor is based on a single-crystal sapphire fiber coated with Pd nanoparticles incorporated TiO2 nanostructured thin film. The template-based sol-gel chemistry was applied to synthesize the nanostructured porous thin films. The sensitivity and response time of the sensor was evaluated for hydrogen concentrations varying from 0.02% to 4%. The effects of temperature on the hydrogen gas sensing properties were investigated from 600 °C to 800 °C.