Insights into the reactivity of Ni-La catalysts for CO2 methanation

Abstract

Efficient catalysts are essential for CO₂ methanation reaction, a key process for sustainable energy applications. This study investigates the structural and chemical properties of Ni-La perovskite-based catalysts synthesized via one-pot and impregnation methods by microwave-assisted synthesis to improve Ni dispersion and phase homogeneity. Reduction temperature emerges as a key factor influencing catalyst structure and performance. Catalysts reduced at lower temperatures retain perovskite structures, leading to enhanced metal-support interactions, which are crucial for CO₂ activation and methane production. In contrast, higher reduction temperatures decompose the perovskite phase into metallic Ni and La₂O₃, which alters the catalytic behavior. The impregnation method enhances Ni dispersion, leading to higher metallic Ni availability and superior catalytic performance. Oxygen vacancies and carbonate species formed on the catalyst surface are identified as central to the reaction mechanism, facilitating CO₂ adsorption and conversion. This research underscores the importance of structure-to-function relationships, focusing on how synthesis methods and reduction conditions shape surface species generation and CO₂ methanation rates. These insights advance the design of highly efficient catalysts for CO₂ conversion, addressing environmental challenges and fostering sustainable energy solutions.