The Dual‐Active‐Site Catalysts Containing Atomically Dispersed Pr <sup>3+</sup> with Ni/CeO <sub>2</sub> for CO <sub>2</sub> Hydrogenation to Methane
Neha Choudhary, Navdeep Srivastava, Harshini V. Annadata, Biplab Ghosh, Patrick Da Costa
Abstract
Abstract In this study, uniformly dispersed Pr 3+ as an isolated atom over Ni/CeO 2 catalyst (Ni‐Pr/CeO 2 ) is designed to enhance catalytic activity for CO 2 methanation, achieving an impressive 87% conversion with ≈100% CH 4 selectivity at 300 °C temperature. In contrast, the traditional Ni/CeO 2 and NiPr/CeO 2 ‐imp catalysts exhibit poor conversion and selectivity, highlighting the proof of concept on the advantage of atomic‐scale dispersion. Structural analysis via PXRD, XAS, and XPS confirms the successful incorporation of Pr 3+ into the CeO 2 lattice by creating defects. XPS and XAS studies further reveal a significant increase in oxygen vacancies, a key factor in enhancing catalytic performance at lower reaction temperatures. STEM‐EDS analysis confirms the ultra‐dispersion of Pr 3+ (≈7 wt.%) over CeO 2 , ensuring a highly active catalyst surface. H 2 ‐TPR and CO 2 ‐TPD results suggest that the Pr 3+ doping enhances the catalytic activity by decreasing the reduction temperature and increasing basic sites. Additionally, long‐term stability tests demonstrate no significant loss in activity over 40 h, confirming the catalyst's robustness and recyclability. This work provides critical insights into the structure‐activity relationship of Pr 3+ ‐modified Ni/CeO 2 catalysts, emphasizing the role of oxygen vacancies in optimizing CO 2 hydrogenation efficiency.