Proton Conducting Perovskite-Type Ceramics for Fiber Optic Sensors for Hydrogen Monitoring at High Temperature

A fiber optical sensor has been developed by coating proton conducting perovskite oxide (Sr(Ce(0.8)Zr(0.1)) Y(0.1)O(2.95), SCZY) thin film on the long-period fiber grating (LPFG) for high temperature in situ measurement of bulk hydrogen in gas mixtures relevant to the fossil-and biomass-derived syngas. In this paper, we investigate in the H(2)-sensing mechanism of the SCZY-LPFG sensor. The high temperature H(2) adsorbance in the SCZY, the SCZY electric conductivity in H(2), and the resonant wavelength shift of the SCZY-LPFG (del lambda(R,H2)) have been experimentally studied to understand the effect of operation temperature on the sensor's sensitivity to H(2). Because of the activation process of the H(2) reaction with the perovskite oxide, increasing temperature benefits the H(2) uptake in the SCZY phase and the sensitivity of the SCZY-LPFG sensor. However, the thermal stability of the LPFG and the microstructure of the SCZY nanocrystalline film limit the application temperature of the fiber optic sensor.