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

Engineering the interfacial interaction between the active metal element and support material is a promising strategy for improving the performance of catalysts toward CO<INF>2</INF> methanation. Herein, the Ni-doped rare-earth metal-based A-site substituted perovskite-type oxide catalysts (Ni/AMnO<INF>3</INF>; A = Sm, La, Nd, Ce, Pr) were synthesized by auto-combustion method, thoroughly characterized, and evaluated for CO<INF>2</INF> 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/CeMnO<INF>3</INF> catalyst exhibited a higher CO<INF>2</INF> conversion rate of 6.6 x 10-5 mol<INF>CO<INF>2</INF></INF> g<INF>cat</INF>-1 s-1 and high selectivity towards CH<INF>4</INF> formation due to the surface composition of the active sites and capability to activate CO<INF>2</INF> 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 CO<INF>2</INF> methanation reaction.