A novel concept for in situ gas-phase laser Raman spectroscopy for solid oxide fuel cell research

A planar solid oxide fuel cell (SOFC) operated with hydrogen at T = 1,123 K was equipped with an optically transparent anode flow field to apply species concentration measurements by 1D laser Raman scattering. The flow channels had a cross section of 3 mm x 4 mm and a length of 40 mm. The beam from a pulsed high-power frequency-doubled Nd:YAG laser (lambda = 532 nm) was directed through one channel and the Raman-scattered light from different molecular species was imaged onto an intensified CCD camera. The main goal of the study was an assessment of the potential of this experimental configuration for a quantitative determination of local gas concentrations. The paper describes the configuration of the optically accessible SOFC, the laser system and optical setup for 1D Raman spectroscopy as well as the challenges associated with the measurements. Important aspects like laser pulse shaping, signal background and signal quality are addressed. Examples of measured species concentration profiles are presented.