Development of Ni-doped A-site lanthanides-based perovskite-type oxide catalysts for CO2 methanation by auto-combustion method

Abstract

Engineering the interfacial interaction between the active metal element and support material is a promising strategy for improving the performance of catalysts toward CO₂ methanation. Herein, the Ni-doped rare-earth metal-based A-site substituted perovskite-type oxide catalysts (Ni/AMnO₃; A = Sm, La, Nd, Ce, Pr) were synthesized by auto-combustion method, thoroughly characterized, and evaluated for CO₂ methanation reaction. The XRD analysis confirmed the perovskite structure and the formation of nano-size particles with crystallite sizes ranging from 18 to 47 nm. The Ni/CeMnO₃ catalyst exhibited a higher CO₂ conversion rate of 6.6 × 10⁻⁵ mol_CO2 g_cat⁻¹ s⁻¹ and high selectivity towards CH₄ formation due to the surface composition of the active sites and capability to activate CO₂ molecules under redox property adopted associative and dissociative mechanisms. The higher activity of the catalyst could be attributed to the strong metal–support interface, available active sites, surface basicity, and higher surface area. XRD analysis of spent catalysts showed enlarged crystallite size, indicating particle aggregation during the reaction; nevertheless, the cerium-containing catalyst displayed the least increase, demonstrating resilience, structural stability, and potential for CO₂ methanation reaction.