Efficient methane reforming at proper reaction environment for the highly active and stable fibrous perovskite catalyst

The purpose of this work is to investigate proper hydrogen production methods from methane through the parametric study for the highly active and stable nanofibrous perovskite catalyst. A ruthenium doped lanthanide chromate (LaCr_0.8Ru_0.2O₃) micro-fibrous perovskite catalyst is prepared and fixed to focus on the effect of reaction environments such as steam, partial oxidation and autothermal conditions. Temperatures, H₂O/C and O₂/C ratios were occasionally changed for the investigation of the effects and the optimization conditions. At the same perovskite catalyst system, the reaction at the autothermal atmosphere is the most effective conditions in terms of both CH₄ conversion and H₂ production, which was comparable to the theoretical calculations. It is found that conversion increases with oxygen at even low temperature while the H₂ productivity increases with much stable behavior at steam condition. These are more obvious at the elevated temperature with each optimized H₂O and O₂ amounts for high activity by high activation energy. Time-on-stream runs conducted on these three reactions with each optimized conditions of 50 h at 800 °C, H₂O/C = 3 and O₂/C = 0.5. The perovskite micro-fiber catalyst at autothermal condition shows excellent CH₄ conversion of over 95%, H₂ production of around 70%, and even H₂/CO of over 4. On the other hand, the reactivity at the steam condition is lower and even slow. The durability at the partial oxidation condition starts to decrease after 10 h due to the instability of the perovskite at the extremely oxidative concentration which causes a relatively high coke formation. Therefore, it is worthwhile in suggesting proper autothermal reaction conditions for the highly active and stable perovskite catalyst like LaCr_0.8Ru_0.2O₃ micro-fibers.