Catalytic coatings on steel for low-temperature propane prereforming to solid oxide fuel cell (SOFC) application

摘要

Catalyst layers (4-20 μm) of rhodium (1 wt%) supported on alumina, titania, and ceria-zirconia (Ce_(0.5)Zr_(0.5)O_2) were coated on stainless-steel corrugated sheets by dip-coating in very stable colloidal dispersions of nanoparticles in water. Catalytic performances were studied for low-temperature (≤500 °C) steam reforming of propane at a steam to carbon ratio equal to 3 and low contact time (≈0.01 s). The best catalytic activity for propane steam reforming was observed for titania and ceria-zirconia supports for which propane conversion started at 250 °C and was more than three times better at 350 °C than conversion measured on alumina catalyst. For all catalysts a first-order kinetics was found with respect to propane at 500 °C. Addition of PEG 2000 in titania and ceria-zirconia sols eliminated the film cracking observed without additive with these supports. Besides, the PEG addition strongly expanded the porosity of the layers, so that full catalytic efficiency was maintained when the thickness of the ceria-zirconia and titania films was increased.