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

Nickel (Ni)-based catalysts are widely used for CO 2 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 CO 2 . This study reveals that the Ni supported on praseodymium oxide (PrO x ) significantly enhanced low-temperature CO 2 methanation activity. This enhancement was primarily attributed to the dual role of PrO x : promoting CO 2 activation and modifying the reducibility of Ni active sites. PrO x facilitated the formation of oxygen vacancies (O v ) through the valence state transition (Pr 3+ ↔ Pr 4+ ), providing electron donor sites for direct CO 2 dissociation (CO 2 → CO + O*). Furthermore, metal-support interaction (MSI) between Ni and PrO x enhanced the reducibility of Ni 2+ to Ni 0 , inducing a higher density of hydrogen activation sites for the hydrogenation of CO 2 . The integration of these properties induced a high efficiency of the CO 2 methanation pathway by enhancing reactant activation efficiency. These findings demonstrate that the synergistic interaction between Ni and PrO x enhances CO 2 methanation by simultaneously improving Ni site reducibility and providing abundant oxygen vacancies for CO 2 activation, indicating PrO x as a highly effective support material for low-temperature CO 2 methanation catalysts. • Superior low-temperature activity of Ni/PrO x catalysts for CO 2 methanation. • Superior structural oxygen mobility of PrO x facilitated oxygen vacancy formation. • Surface oxygen vacancies enhanced the low-temperature CO 2 cleavage reaction pathway. • Ni-Pr interaction strongly promoted redox property of Ni 2+ to Ni 0 for H 2 activation. • Enhanced reactant activation efficiency improved low-temperature CO 2 methanation.