La–Ce–Ni–O monolithic perovskite catalysts potential for gasoline autothermal reforming system

Abstract

Hydrogen generation from gasoline is essentially one of the critical technologies for the commercialization of small-scale fuel cells auxiliary/backup power systems, so catalysts suitable for autothermal reforming (ATR) of gasoline are desperately needed. La 0.8Ce 0.2NiO 3 with a crystal structure of perovskite was developed both in pellet and on cordierite substrate by citrate method. Autothermal reforming of gasoline or its surrogates, n-octane with or without thiophene additive, was carried out on either bulk perovskite pellet or monolithic perovskite catalyst. During the 220-h long-term test, the pellet catalyst exhibited high thermal stability and activity with hydrogen yield approaching to the theoretical maximum value and only minor amount of CH 4 slipping through. It possessed fairly good sulfur tolerance, almost immune to 5 ppmw sulfur although could still be seriously poisoned when subjected to high concentration of sulfur or gasoline. The monolithic perovskite catalysts were developed by screening slurries, binders as well as substrates with or without pre-washcoating CeZrO 2. The monolithic La 0.8Ce 0.2NiO 3 formed in situ on the raw cordierite monolith could be an effective catalyst for ATR of gasoline, exhibiting superior performance to the catalyst of 0.3 wt.%Rh/CeO 2–ZrO 2/cordierite at a temperature range 650–800 °C. On whatever the pellet or monolithic catalysts, the active sites were presumably the in situ reduced Ni 0 which were well dispersed and stabilized by the perovskite crystal structure. The good performances of La 0.8Ce 0.2NiO 3, better thermal stability and immunity to carbon foul and sulfur poison than LaNiO 3 could be ascribed to the increased oxygen mobility with the presence of sesquioxide of cerium.