Low-temperature catalytic CO2 methanation over nickel supported on praseodymium oxide

Abstract

Nickel (Ni)-based catalysts are widely used for CO2 methanation due to their cost-effectiveness compared to noble metals and high efficiency. However, their catalytic performance at low temperatures remains a significant challenge, primarily due to the limited activation of CO2. This study reveals that the Ni supported on praseodymium oxide (PrOx) significantly enhanced low-temperature CO2 methanation activity. This enhancement was primarily attributed to the dual role of PrOx: promoting CO2 activation and modifying the reducibility of Ni active sites. PrOx facilitated the formation of oxygen vacancies (Ov) through the valence state transition (Pr3+ <-> Pr4+), providing electron donor sites for direct CO2 dissociation (CO2 -> CO + O*). Furthermore, metal-support interaction (MSI) between Ni and PrOx enhanced the reducibility of Ni2+ to Ni0 , inducing a higher density of hydrogen activation sites for the hydrogenation of CO2. The integration of these properties induced a high efficiency of the CO2 methanation pathway by enhancing reactant activation efficiency. These findings demonstrate that the synergistic interaction between Ni and PrOx enhances CO2 methanation by simultaneously improving Ni site reducibility and providing abundant oxygen vacancies for CO2 activation, indicating PrOx as a highly effective support material for low-temperature CO2 methanation catalysts.