Oxidative conversion of methane to syngas over LaNiO₃ perovskite with or without simultaneous steam and CO₂ reforming reactions: influence of partial substitution of La and Ni

Abstract

Selective partial oxidation of methane to syngas over LaNiO₃, La_0.8Ca(or Sr)_0.2NiO₃ and LaNi_1-xCo_xO₃(wherex = 0.2-1) perovskites at extremely short contact time (≈0.8 ms) has been investigated. Also, simultaneous oxidative conversion and steam and CO₂ reforming of methane to syngas over LaNiO₃ at short contact time (≈9 ms) has been studied at different temperatures and CH₄/O₂ feed ratios. The catalysts, before and after reaction, were characterized by XRD and SEM. LaNiO₃ perovskite shows high activity and selectivity in the oxidative conversion of methane to syngas. However, the partial substitution of its La by Ca or Sr and also the partial or complete substitution of its Ni by Co causes a large decrease in both its activity and its selectivity. LaNiO₃ is transformed to its catalytically active form, Ni⁰/La₂O₃, during the initial period of the process. This catalyst shows very good performance in the simultaneous oxidative conversion (which is exothermic) and steam and CO₂ reforming reactions (which are endothermic) of methane to syngas, at short contact time, operating in a most energy efficient manner and also requiring only a little or no external energy.