Steam reforming of methane on LaNi_xFe_(1-x)O_3 (0 <= x < = 1) perovslites. Reactivity and characterisation after test

摘要

LaNi_xFe_(1-x)O_3 perovskites (0 < = x < = 1) are efficient catalysts in steam reforming of methane (optimum ratio H_2O/CH_4 = 1) for syngas production. For low x values (x < = 0.4), the three-metal structure is partly maintained with a strong interaction between free nickel and the pervoskite, the carbon formation is limited and the regeneration of the three-metal perovskite by recalcination is possible. For higher x values (x > 0.4), only a bimetallic LaFeO_3 is maintained during the reaction and the catalysts perform as free nickel on LaFeO_3 and La_2O_3. Coke formation becomes important and the regeneration gives into distinct perovskites, LaFeO_3 and LaNiO_3. The increase in H_2O/CH_4 from 1 to 3 enhances the oxidating power, leads to a decrease in the activity and favours CO_2 formation.