Hydrogen production from ethanol steam reforming over Ir/CeO_2 catalysts: Enhanced stability by PrO_x promotion

摘要

We studied ethanol steam reforming over Ir/Ce_(0.9)Pr_(0.1)O_2 and Ir/CeO_2 catalysts comparatively with respect to activity and stability. We found that PrO_x-doping have significantly promoted the oxygen storage capacity and thermal stability of the catalysts by incorporation into the ceria lattice. Ethanol was readily converted to hydrogen, methane and carbon oxides at 773 K over the Ir/Ce_(0.9)Pr_(0.1)O_2 catalyst, and this is 100 K lower than that found for the Ir/CeO_2 catalyst. Moreover, the PrOx-doped catalyst was stable toward ethanol steam reforming at 923 K for 300 h without an apparent variation in ethanol conversion and product distribution. However, the severe aggregation of ceria particles and heavy coke deposition were observed on the Ir/CeO_2 catalyst, resulting in remarkable deactivation under the same reaction conditions.