Modulating CO2 methanation activity on Ni/CeO2 catalysts by tuning ceria facet-induced metal-support interaction

Comprehending the metal-support interactions (MSI) as well as interface structures plays a crucial role in creating efficient interface sites. However, the interfacial nature is influenced by multiple structural factors, making it challenging to establish a direct correlation between interfacial sites and CO2 methanation activity. Herein, the CeO2 with uniform facets were used as supports to study the influence of facet-induced MSI on methanation performance. CeO2 cubes with (1 0 0) facet and octahedrons with (1 1 1) facet was fabricated over Ni/CeO2 by altering hydrothermal parameters. (HR)TEM, XPS and Raman characterizations etc. revealed that the presence of embedded MSI structures in Ni/CeO2-Cub resulted in the well-dispersed Ni0. The embedded Ni-CeO2 interaction owned a maximized interface with more surface oxygen vacancies. The FT-IR spectrum indicated that the synergistic effect of H2 dissociation on Ni NPs surfaces and CO2 activation in adjacent surface oxygen vacancies occurred in Ni-CeO2 interfaces, improving CO2 methanation activity with a large number of formates. CO2 conversion rate for Ni/CeO2-Cub was 18.4 times as high as that for Ni/SiO2 without MSI at 548 K. This study elucidated how the facet-induced interfaces impacted the methanation activity, providing new ideas for the development of efficient CO2 hydrogenation catalysts.