Fiber optic hydrogen sensors with sol–gel WO3 coatings

Fiber-optic hydrogen gas sensor using Pt catalyzed tungsten trioxide (WO3) was proposed and characterized in this paper. Pt-loaded WO3 coatings prepared with sol–gel method were deposited on Bragg fibers. Shift of fiber Bragg wavelength is observed with different hydrogen concentration. Experimental results showed that highest sensitivity existed when the weight ratio of Pt was 6.5% in the Pt-loaded WO3 coating. The response time of the hydrogen sensor was about 10 s.