High Stability of the Ni–YCe/Diatomite Catalyst for CO<sub>2</sub> Methanation: The Synergistic Coupling of Citric Acid and Y<sub>2</sub>O<sub>3</sub>
Qinghe Liu, Sen Wang, Shupei Lv, Fei Han, Jing Ouyang
Abstract
Carbon dioxide (CO 2 ) methanation exhibits great potential for achieving high-value utilization of CO 2 to fulfill the goal of carbon neutrality. Here, a novel nickel–yttrium–cerium/diatomite (Ni–YCe/Dia) composite was constructed by the in situ growth of thin membrane-like Ni–YCe oxides on the Dia template. Distinct from conventional Ni-based catalysts, Dia improved the dispersion of Ni–YCe oxide nanoparticles and provided extra hydroxyl groups for CO 2 adsorption; citric acid remarkably enhanced the dispersion of Ni species, thus creating favorable conditions for the rapid dissociation of H 2; most importantly, introducing Y species improved the dispersion of Ni nanoparticles and the anti-carbon deposition capacity of the catalysts. Such characteristics endow Ni–YCe/Dia composites with exceptional catalytic activity for CO 2 methanation, with more than 85% CO 2 conversion and 99% CH 4 selectivity in a stability test up to 150 h, which is better than most reported Ni-based catalysts. In situ DRIFTS analysis revealed that the −OH groups on the surface of Dia exhibited a remarkable ability to activate CO 2 . This study provides a new perspective on the rational regulating of structural assemblage between metal oxides and natural minerals for high-performance CO 2 methanation.