Intermediate temperature SOFC fed by biogas: external reformer development

This work is focused on the development of an external reformer of methane using Ni-based structured and unstructured catalysts. Nickel is so far the most active catalyst for the DRM, but also highly prone to carbon formation, because, together with the ability to activate the C-H bond, Ni has an high affinity to carbon. The Ni particle size has a strong effect on the carbon tolerance of the catalyst, therefore, the stabilization of small Ni nanoparticles at high temperatures is a promising way for the lifetime increase. The catalysts were prepared by wet impregnation of active phase (10wt.% Ni) on γ-Al2O3 or Ru(0.05 wt.%)/γ-Al2O3 and wash coating deposition of the carrier on cordierite monoliths. The samples were characterized by XRD, FE-SEM, H2-TPR, BET techniques and the catalytic activity for DRM was evaluated at 800°C during time on stream. Catalytic tests showed that Ni particles, obtained by reduction of Ni-α species, were active for the DRM reaction with low carbon formation, whereas catalysts with large amount of Ni-β deactivated rapidly during TOS without carbon formation.